# Global Trends in Research of NF-κB in Melanoma from 2000 to 2021: A Study of Bibliometric Analysis

Authors: Jun Wang; Xuan Liao; Xiao Jiang; Hongwei Liu
Journal: Journal of Oncology
 (2022)

---

## Abstract

In the pathogenesis of melanoma, NF-κB is a key signaling pathway. Appling bibliometric analysis, we identify the frontiers and hotspots about NF-κB in melanoma, as well as distinguishing features of scientific research and output all over the world during the past 22 years. 2226 publications published from 2000 to 2021 and related information were retrieved based on Science Citation Index Expanded (SCI-expanded) of Web of Science Core Collection (WoSCC). VOSviewer and Citespace were used to analyze bibliometric indicators and visualize the hotspots and research trend of studies on NF-κB in melanoma. The results indicated that despite fluctuations, the number of publications (Np) related to the research of NF-κB in melanoma per year increased over the past 22 years. The USA had the most publications. H-index and the number of citations (Nc) of the USA were also in the first place. PloS One was the most productive journal, and League of European Research Universities (LERU) was the most productive affiliation. Recently, the keywords “NF-kappa-b,” “melanoma,” “apoptosis,” “expression,” “activation,” “cancer,” and “metastasis” appeared most frequently. Our study suggested that articles associated with NF-κB in melanoma tend to increase. In this field, the USA was an influential country and a big producer. Most publications focused on clinical and basic research in the past 22 years, and keywords “tumor necrosis factor” and “trail induced apoptosis” had the highest burst strength.


---

## Body

## 1. Introduction

Melanoma refers to a tumor derived from melanocytes with a high degree of malignancy. Abnormal and excessive proliferation of melanocytes in neural crest is the main cause of its pathogenesis [1]. The incidence rate of melanoma is increasing worldwide. 95% of melanoma patients died of brain metastasis at the end of the disease [2]. The annual mortality of patients with melanoma is higher than 3.5%, and the 5-year survival rate of patients with metastatic melanoma is about 15%∼20% [3]. About 10% of melanoma cases are diagnosed as advanced, which has metastasized and cannot be removed [4]. Inhibiting the invasion and migration of melanoma is critical to ameliorate the survival rate of melanoma patients, and it is urgent to further explore the molecular mechanism of melanoma and seek a treatment scheme with good curative effect to improve the prognosis of patients. Epidemiological studies show that the incidence rate of melanoma is increasing worldwide. It may be due to the early diagnosis and improvement of health cognition obtained by skin biopsy, thus diagnosing a large number of cases with very thin and marginal cutaneous melanoma [5]. Studies have shown that the joint action of internal factors (such as genetic factors) and external factors (such as ultraviolet light) leads to the pathogenesis of melanoma [4]. Multiple signaling pathways play an important role in the pathogenesis of melanoma [6–8].As an excellent transcription factor, nuclear factor-kappa B (NF-κB) is a significant role in the invasion and metastasis of many cancers [9]. It also plays a variety of roles in cell survival, differentiation, and proliferation [10]. The NF-κB transcription factor family consists of five different proteins: rela, RelB, c-Rel, P100, and P150 [11]. It is one of the targets of tumor therapy [12]. The activation of NF-κB has been proposed as an event that promotes melanoma tumor progression [13]. Constitutively activated NF-κB signaling pathway plays an important role in melanoma initiation, progression, invasion, metastasis, and resistance to chemotherapy and immunotherapy, and it is the convergence point of dysregulated cellular signaling pathways in melanoma [14]. Shomali et al.’s study suggested that HSP90 may act as a potential therapeutic target in melanoma. However, more studies are needed to determine the exact role of HSP90 and its association with HMG genes [15]. At present, there are mainly immunotherapy, braf/mek inhibitors, and other methods for the treatment of melanoma. In recent years, there are more and more studies on NF-κb in melanoma [16–18]. Professors and scholars continue to make breakthroughs in the field. The emergence of new concepts and the introduction of new technologies are also great challenges for researchers. Therefore, it is necessary to summarize the research progress in this field. Bibliometrics is defined by Pritchard as “the application of mathematical and statistical methods to books and other media.” Historical bibliometrists recognize that adding time and space dimensions to bibliometric analysis can bring new insights into knowledge development and academic records [19]. Bibliometric methods are majorly composed of citation analysis, which is the source of influencing factors. The number of citations of the research center is considered to be high. Therefore, the top ranked and highly cited papers provide evidence and information for research trends and scientific progress in specific fields [20]. Bibliometrics and visual analysis can effectively support information integration to improve the understanding of research activities [21]. Over the recent years, bibliometric indicators are increasingly used to evaluate and manage research activities [22]. Bibliometrics is a method of quantifying the research object, which is often used to determine the law of literature. Unlike the traditional narrative review, which depends on the experience and knowledge of researchers, bibliometric analysis takes science as a knowledge generation system [23]. Nowadays, there are many bibliometric research results, such as metformin [21], tourism [24], artemisinin [25], diabetic foot ulcers [26], and macrophages associated with acute lung injury [27]. Nevertheless, bibliometric research on NF-κB in melanoma is still a blank. Therefore, the purpose of this study is to systematically analyze study of NF-κB in melanoma to make a scientific and comprehensive evaluation of the hotspots and research status in the field.


## 2. Materials and Methods

### 2.1. Data Source and Search Strategy

The publications related to NF-κB in melanoma from 2000 to 2021 were obtained based on the Science Citation Index Expanded (SCI-E) of the Web of Science Core Collection (WOSCC) on April 22, 2022. The retrieval topic was “(TS = (Melanoma)) AND (TS = (NF-kappa B) OR TS = (NF-kB) OR TS = (nuclear transcription factor-κB)),” and only the “review” and “article” written in English were included in this study. 2226 publications meeting the search criteria in total were selected to carry out further analysis.


### 2.2. Analytical Methods

With CiteSpace 5.8.R3 and VOSviewer 1.6.16, data visualization and analysis were carried out. CiteSpace, developed by Professor Chaomei Chen, is a piece of software which can visualize networks among research hotspots and documents as well as citation collaboration [28]. As a software focusing on bibliometrics network, VOSviewer can well analyze literature information, such as keyword cooccurrence, cocitation, and coauthorship. In conclusion, these analytical tools provide an objective and different view of development. The number of publications (Np), the number of citations without self-citations (Nc), and the academic contribution of researchers are evaluated by the H-index, affiliation, country, or journal [27]. In 2005, Hirsch first introduced the H-index. As a comprehensive scoring, it can well assess the importance and wide-ranging impact for cumulative research contributions of scientists [29].


## 2.1. Data Source and Search Strategy

The publications related to NF-κB in melanoma from 2000 to 2021 were obtained based on the Science Citation Index Expanded (SCI-E) of the Web of Science Core Collection (WOSCC) on April 22, 2022. The retrieval topic was “(TS = (Melanoma)) AND (TS = (NF-kappa B) OR TS = (NF-kB) OR TS = (nuclear transcription factor-κB)),” and only the “review” and “article” written in English were included in this study. 2226 publications meeting the search criteria in total were selected to carry out further analysis.


## 2.2. Analytical Methods

With CiteSpace 5.8.R3 and VOSviewer 1.6.16, data visualization and analysis were carried out. CiteSpace, developed by Professor Chaomei Chen, is a piece of software which can visualize networks among research hotspots and documents as well as citation collaboration [28]. As a software focusing on bibliometrics network, VOSviewer can well analyze literature information, such as keyword cooccurrence, cocitation, and coauthorship. In conclusion, these analytical tools provide an objective and different view of development. The number of publications (Np), the number of citations without self-citations (Nc), and the academic contribution of researchers are evaluated by the H-index, affiliation, country, or journal [27]. In 2005, Hirsch first introduced the H-index. As a comprehensive scoring, it can well assess the importance and wide-ranging impact for cumulative research contributions of scientists [29].


## 3. Results

### 3.1. General Statistics

There were 2,226 publications about NF-κB in melanoma from the SCIE of WoSCC during 2000–2021. We found that 75 countries/regions participated in the research field, and these publications were from 623 journals, 2,326 institutions, and 12,830 authors. There were 8,894 keywords included in all publications. Publishing types were divided into two categories: there were 1,827 research articles accounting for 82.08% and 399 reviews. The total Nc of all publications was 118,172, and the Nc per publication was 55.05. The H-index for all retrieved publications was 148. Figure 1(a) shows the fitting curve of the annual trend of the number of papers published. Annual Np is not related to the year of publication. As can be seen from Figure 1(a), the correlation coefficient R2 was only 0.768. Figures 1(a) and 1(b) show the annual Np associated with NF-κB in melanoma. In summary, despite fluctuations in the number of documents issued over the past 22 years, the number of annual papers rose from 34 in 2002 to 156 in 2017.Figure 1
(a) Curve fitting of the total annual growth trend of publications. (b) The number of publications by year over the past 22 years.
(a)(b)


### 3.2. Performance of Country/Region

Over 2000–2021, groups from a total of 75 countries/regions published NF-κB in melanoma-related articles. Figures 2(a) and 2(b) show the cooccurrence of all the countries. The top 10 most productive countries are shown in Table 1 and the number of documents issued by these countries each year is shown in Figure 2(c). The United States produced the most NF-κB in melanoma-related articles, which was 847 publications in the studied period. China, Germany, and Japan were the following countries in terms of Np. The United States also showed the highest Nc of 66218 and H-index of 117. Even though China is the second productive country, its Nc was lower than Japan. Visualized timeline of countries is shown in Figure 2(d). There were six clusters including melanoma, IL-6, ROS, oxidative stress, sulforaphane, and thieleanin.Figure 2
Leading countries. (a) Visual cluster analysis of cooperation among countries. (b) Timeline visualization of cooperation among countries. (c) The number of documents issued by the top ten countries each year. (d) Timeline distribution of the top 6 clusters.
(a)(b)(c)(d)Table 1
Publications in the 10 most productive countries/regions.
RankCountryNpNcH-index1The USA847662181172China50714104583Germany17111693504Japan16414219465South Korea1354902396Italy1316006427India973331338Australia764153379England7568303310France75337232


### 3.3. Affiliation and Author Contributions

A total of 2,326 affiliations and 12,830 authors have contributed to the field of NF-κB in melanoma. Table 2 shows the top 10 affiliations with the highest number of publications. League of European Research Universities (LERU) occupied the first place in Np, and University of Texas System ranked first in Nc and H-index. Although UT MD Anderson Cancer Center ranked 4th in Nc, its H-index was higher than University of California System. To find the most influential researchers in the NF-κB in melanoma field in the last 22 years, according to the H-index and publication number, we ranked the top 10 authors. As the most productive author, Richmond A from Vanderbilt Univ of the United States was with Np of 29 and an H-index of 26. Kuttan G from Amala Canc Res Ctr and Ivanov VN from Columbia University had an H-index of 16 and 14, respectively (Table 3). Author cooccurrence is shown in Figures 3(a) and 3(b), and the top 10 authors with the strongest citation bursts are shown in Figure 3(c). Affiliation cooccurrence is shown in Figures 4(a) and 4(b). Visualized timeline of affiliations is shown in Figure 4(c). There were 12 clusters, and the top 20 authors with the strongest citation bursts are shown in Figure 4(d).Table 2
Publications in the 10 most productive affiliations.
RankAffiliationNpNcH-index1League of European Research Universities (LERU)988880402University of Texas System9713212473University of California System704283344UT MD Anderson Cancer Center699518405Harvard University525859316National Institutes of Health NIH USA526299347Institut National de la Sante et de la Recherche Medicale (Inserm)512351278US Department of Veterans Affairs392261289Veterans Health Administration (VHA)3822612810Helmholtz Association37214024Table 3
Publications in the 10 most productive authors.
RankAuthorAffiliationCountryNPNCH-index1Richmond A.Vanderbilt UniversityThe USA293028262Kuttan G.Amala Cancer Research CenterIndia20879163Ivanov V. N.Columbia UniversityThe USA19541144Li G.University of British ColumbiaCanada16955145Fisher P. B.Virginia Commonwealth UniversityThe USA10616106Aggarwal B. B.University of Texas SystemThe USA144745137Hei, T. K.Columbia UniversityThe USA13456138Kim S. H.Kongju National UniversitySouth Korea13395119Sarkar, D.Virginia Commonwealth UniversityThe USA1311611310Akira, S.Osaka UniversityJapan12569411Figure 3
Author analysis. (a) Visual cluster analysis of cooperation among authors. (b) Timeline visualization of cooperation among authors. (c) Representative burst authors with the strongest citation bursts.
(a)(b)(c)Figure 4
Affiliation analysis. (a) Visual cluster analysis of cooperation among affiliations. (b) Timeline visualization of cooperation among affiliations. (c) Timeline distribution of the top 12 clusters. (d) Representative burst affiliations with the strongest citation bursts.
(a)(b)(c)(d)


### 3.4. Performance of Journal

The 2,226 publications were published in 623 journals. For the all publications, publications in the top 10 productive journals accounted for 19.23% (Table4). PloS One ranked first in Np (62). CANCER RESEARCH had the highest H-index (39) and IF (12.701), and ONCOGENE had the highest Nc (5962). 8 journals were from the United States, 1 journal was from England, and 1 journal was from the Netherlands. Impact factor (IF) is a recognized sign to determine the influence of journals based on the frequency of journal articles cited by other scientific publications. Except that PLoS One has a low impact factor or Oncotarget has been removed from science, other journals have high IF (IF > 5).Table 4
Publications in the 10 most productive journals.
RankJournalNpNcH-indexIF (2020)1PloS One622014263.242Cancer Research5940973912.7013Oncogene575962379.8674Journal of Immunology504168335.4225Journal of Biological Chemistry493467325.1576Clinical Cancer Research3429062612.5317International Journal of Molecular Sciences33855135.9248Cancer Letters Netherlands282160198.6799Journal of Investigative Dermatology28966208.55110Oncotarget2893117Removed


### 3.5. Hotspot Detection and Burst Analysis

Research hotspots and frontiers in a certain field can be reflected by keywords. The top 20 most frequently keywords were NF-kappa-b (1306), melanoma (502), apoptosis (491), expression (457), activation (436), cancer (372), metastasis (213), NF-kappa b (209), melanoma cells (206), gene-expression (193), in-vitro (182), malignant-melanoma (176), inflammation (154), growth (151), human-melanoma cells (148), cells (146), inhibition (146), breast-cancer (138), down-regulation (123), and pathway (123). Keyword clustering and visualization can be carried out through VOSviewer. Due to occurrence >25, 143 keywords reached the specifications and 4 clusters emerged. As shown in Figure5(a), each word in the 143 keywords is represented by a circle, and the frequency of occurrence of keywords is represented by the size of the circle. A connection line is generated when at least one of the two keywords connected to a keyword coexists. The different colors represented the 4 clusters: cluster 1 (in red) and cluster 2 (in green) mainly concentrated in mechanism research; cluster 3 (in yellow) focused on inflammation research; cluster 4 (in blue) focused on basic and clinical researches. As shown in Figure 5(b), based on the average publication year (APY), all keywords were divided into different colors with VOSviewer. Keywords in the recent six years were tumor microenvironment (2017.24), inflammasome (2017.03), autophagy (2016.33), and epithelial-mesenchymal transit (2016.11). Compared with Figures 5(a) and 5(b), the research of anti-inflammation for alleviating melanoma was relatively the latest. As shown in Figure 5(c), the top 7 clusters of keywords were “growth,” “transcription factor,” “rig i,” “metastatic melanoma,” “trail,” “cyclooxygenase 2,” and “reduced glutathione.” We found that “tumor necrosis factor” and “trail induced apoptosis” were with the highest burst strength (Figure 5(d)). Studies have shown that TNF-α treatment of melanoma can induce consistent dedifferentiation [30]. Furthermore, the latest keywords “therapy,” “inflammation,” “proliferation,” and “resistance” emerged in the last 6 years.Figure 5
Keyword analysis. (a) Visual cluster analysis of cooccurrence among keywords. (b) Timeline visualization of keywords. (c) Timeline distribution of the top 7 clusters. (d) Representative burst keywords with the strongest citation bursts.
(a)(b)(c)(d)


### 3.6. Cocitation Analysis

A cocitation relationship was constituted when two or more articles are simultaneously cited by more than one subsequent publication. The higher the cocitation number, the stronger the cocitation relationship, indicating that these articles have high similarity and will produce a common theme. We performed cluster analysis from the cocitation relationship analysis to further delineate the research frontier and obtain the publications with critical citations from a chronological perspective with CiteSpace and VOSviewer. Due to a large number of cited references, we set the minimum citations per reference as 20. Among the 103304 references which were cited by these publications, we selected 181 references for further analysis (Figure6(a)). There were 96 references in cluster 1 (in red), which mainly paid attention to drug therapy and mechanism of melanin. Cluster 2 (in green) mainly paid attention to study on various signaling pathways in cancer. Cluster 3 (in blue) focused on study of TNF-related apoptosis inducing ligand (TRAIL) and NF-κB in melanoma. The subject of cluster 4 (in yellow) was therapeutic effect and mechanism of betulinic acid on tumor. Furthermore, a visualized timeline of clusters was carried out (Figure 6(b)). We found that “NF-kappa B” and “EGF” are early fields in the study of NF-κB in melanoma. However, the current hotspots of NF-κB in melanoma are on “EMT,” “apoptosis,” and “duck.” Finally, a reference burst was conducted. Figure 6(c) shows the top 20 references that possessed the strongest citation bursts and the most representative references in terms of burst strength, burst duration, and burst time. The study of Griffith TS et al. (1998) possesses the highest bursts strength. The latest reference was the paper written by Hoesel B; in his article, he provided an overview that during cancer and inflammation, NF-kappa B and other signaling molecules had the most relevant modes of cooperativity and crosstalk. The top 10 cocited journals are shown in Table 5, and the most frequently cited journal is Cancer Res.Figure 6
Cocited reference analysis. (a) Visual cluster analysis of cooccurrence among cocited references. (b) Timeline distribution of the top 10 clusters. (c) Representative burst cocited references with the strongest citation bursts.
(a)(b)(c)Table 5
Top 10 cocited journals.
IdSourceCitationsTotal link strength1Cancer Research67966254922Journal Biological Chemistry65555899803Nature43234236034Proceedings of the National Academy of Sciences of the USA41394197715Oncogene39343621606Journal of Immunology38943613227Cell33573331828Science28512778449Clinical Cancer Research238322792010PloS One1779216877


### 3.7. Bibliographic Coupling Analysis

Bibliographic coupling refers to the phenomenon that two or more documents cite one document at the same time. Ranked by total link strength, top 10 authors in bibliographic coupling analysis were Richmond, A (7139), Fisher, Paul B. (5259), Ivanov, Vn (4723), Akira, Shizuo (4535), Richmond, Ann (4398), Sarkar, Devanand (4001), Ronai, Z. (3571), Zhang, Xu Dong (3178), Amiri, Ki (3150), and Colonna, Marco (3134). The top ten countries were the USA (228698), China (95306), Germany (75474), Italy (53416), Japan (52034), Australia (33843), South Korea (31695), Spain (29333), India (28982), and England (24595). The top 10 publications were Amiri (2005, 282), Almasan (2003, 270), Leblanc (2003, 254), Richmond (2002, 243), Raman (2007, 236), Soengas (2003, 230), Basseres (2006, 212), Cui (2014, 211), Kumar (2006, 209), and Gitlin (2006, 206). The top 10 affiliations were Vanderbilt Univ (19469), Univ Texas (14945) Columbia Univ (10203), Osaka Univ (10070), Univ Texas MD Anderson Canc Ctr (8976), Kyoto Univ (8676), NCI (7604), Harvard Univ (7121), Washington Univ (7079), and Dept Vet Affairs (6892). The top 10 journals were Oncogene (13026), Journal of Immunology (10892), Cancer Research (10041), Journal of Biological Chemistry (9912), Journal of Virology (8377), Clinical Cancer Research (7501), PloS One (6761), Cancer Biology & Therapy (4703), International Journal of Molecular Sciences (4573), and Journal of Investigative Dermatology (4529). Figure7 shows the bibliographic coupling analysis.Figure 7
Bibliographic coupling analysis. (a) Author cooccurrence. (b) Country cooccurrence. (c) Publication cooccurrence. (d) Affiliation cooccurrence. (e) Journal cooccurrence.
(a)(b)(c)(d)(e)


## 3.1. General Statistics

There were 2,226 publications about NF-κB in melanoma from the SCIE of WoSCC during 2000–2021. We found that 75 countries/regions participated in the research field, and these publications were from 623 journals, 2,326 institutions, and 12,830 authors. There were 8,894 keywords included in all publications. Publishing types were divided into two categories: there were 1,827 research articles accounting for 82.08% and 399 reviews. The total Nc of all publications was 118,172, and the Nc per publication was 55.05. The H-index for all retrieved publications was 148. Figure 1(a) shows the fitting curve of the annual trend of the number of papers published. Annual Np is not related to the year of publication. As can be seen from Figure 1(a), the correlation coefficient R2 was only 0.768. Figures 1(a) and 1(b) show the annual Np associated with NF-κB in melanoma. In summary, despite fluctuations in the number of documents issued over the past 22 years, the number of annual papers rose from 34 in 2002 to 156 in 2017.Figure 1
(a) Curve fitting of the total annual growth trend of publications. (b) The number of publications by year over the past 22 years.
(a)(b)


## 3.2. Performance of Country/Region

Over 2000–2021, groups from a total of 75 countries/regions published NF-κB in melanoma-related articles. Figures 2(a) and 2(b) show the cooccurrence of all the countries. The top 10 most productive countries are shown in Table 1 and the number of documents issued by these countries each year is shown in Figure 2(c). The United States produced the most NF-κB in melanoma-related articles, which was 847 publications in the studied period. China, Germany, and Japan were the following countries in terms of Np. The United States also showed the highest Nc of 66218 and H-index of 117. Even though China is the second productive country, its Nc was lower than Japan. Visualized timeline of countries is shown in Figure 2(d). There were six clusters including melanoma, IL-6, ROS, oxidative stress, sulforaphane, and thieleanin.Figure 2
Leading countries. (a) Visual cluster analysis of cooperation among countries. (b) Timeline visualization of cooperation among countries. (c) The number of documents issued by the top ten countries each year. (d) Timeline distribution of the top 6 clusters.
(a)(b)(c)(d)Table 1
Publications in the 10 most productive countries/regions.
RankCountryNpNcH-index1The USA847662181172China50714104583Germany17111693504Japan16414219465South Korea1354902396Italy1316006427India973331338Australia764153379England7568303310France75337232


## 3.3. Affiliation and Author Contributions

A total of 2,326 affiliations and 12,830 authors have contributed to the field of NF-κB in melanoma. Table 2 shows the top 10 affiliations with the highest number of publications. League of European Research Universities (LERU) occupied the first place in Np, and University of Texas System ranked first in Nc and H-index. Although UT MD Anderson Cancer Center ranked 4th in Nc, its H-index was higher than University of California System. To find the most influential researchers in the NF-κB in melanoma field in the last 22 years, according to the H-index and publication number, we ranked the top 10 authors. As the most productive author, Richmond A from Vanderbilt Univ of the United States was with Np of 29 and an H-index of 26. Kuttan G from Amala Canc Res Ctr and Ivanov VN from Columbia University had an H-index of 16 and 14, respectively (Table 3). Author cooccurrence is shown in Figures 3(a) and 3(b), and the top 10 authors with the strongest citation bursts are shown in Figure 3(c). Affiliation cooccurrence is shown in Figures 4(a) and 4(b). Visualized timeline of affiliations is shown in Figure 4(c). There were 12 clusters, and the top 20 authors with the strongest citation bursts are shown in Figure 4(d).Table 2
Publications in the 10 most productive affiliations.
RankAffiliationNpNcH-index1League of European Research Universities (LERU)988880402University of Texas System9713212473University of California System704283344UT MD Anderson Cancer Center699518405Harvard University525859316National Institutes of Health NIH USA526299347Institut National de la Sante et de la Recherche Medicale (Inserm)512351278US Department of Veterans Affairs392261289Veterans Health Administration (VHA)3822612810Helmholtz Association37214024Table 3
Publications in the 10 most productive authors.
RankAuthorAffiliationCountryNPNCH-index1Richmond A.Vanderbilt UniversityThe USA293028262Kuttan G.Amala Cancer Research CenterIndia20879163Ivanov V. N.Columbia UniversityThe USA19541144Li G.University of British ColumbiaCanada16955145Fisher P. B.Virginia Commonwealth UniversityThe USA10616106Aggarwal B. B.University of Texas SystemThe USA144745137Hei, T. K.Columbia UniversityThe USA13456138Kim S. H.Kongju National UniversitySouth Korea13395119Sarkar, D.Virginia Commonwealth UniversityThe USA1311611310Akira, S.Osaka UniversityJapan12569411Figure 3
Author analysis. (a) Visual cluster analysis of cooperation among authors. (b) Timeline visualization of cooperation among authors. (c) Representative burst authors with the strongest citation bursts.
(a)(b)(c)Figure 4
Affiliation analysis. (a) Visual cluster analysis of cooperation among affiliations. (b) Timeline visualization of cooperation among affiliations. (c) Timeline distribution of the top 12 clusters. (d) Representative burst affiliations with the strongest citation bursts.
(a)(b)(c)(d)


## 3.4. Performance of Journal

The 2,226 publications were published in 623 journals. For the all publications, publications in the top 10 productive journals accounted for 19.23% (Table4). PloS One ranked first in Np (62). CANCER RESEARCH had the highest H-index (39) and IF (12.701), and ONCOGENE had the highest Nc (5962). 8 journals were from the United States, 1 journal was from England, and 1 journal was from the Netherlands. Impact factor (IF) is a recognized sign to determine the influence of journals based on the frequency of journal articles cited by other scientific publications. Except that PLoS One has a low impact factor or Oncotarget has been removed from science, other journals have high IF (IF > 5).Table 4
Publications in the 10 most productive journals.
RankJournalNpNcH-indexIF (2020)1PloS One622014263.242Cancer Research5940973912.7013Oncogene575962379.8674Journal of Immunology504168335.4225Journal of Biological Chemistry493467325.1576Clinical Cancer Research3429062612.5317International Journal of Molecular Sciences33855135.9248Cancer Letters Netherlands282160198.6799Journal of Investigative Dermatology28966208.55110Oncotarget2893117Removed


## 3.5. Hotspot Detection and Burst Analysis

Research hotspots and frontiers in a certain field can be reflected by keywords. The top 20 most frequently keywords were NF-kappa-b (1306), melanoma (502), apoptosis (491), expression (457), activation (436), cancer (372), metastasis (213), NF-kappa b (209), melanoma cells (206), gene-expression (193), in-vitro (182), malignant-melanoma (176), inflammation (154), growth (151), human-melanoma cells (148), cells (146), inhibition (146), breast-cancer (138), down-regulation (123), and pathway (123). Keyword clustering and visualization can be carried out through VOSviewer. Due to occurrence >25, 143 keywords reached the specifications and 4 clusters emerged. As shown in Figure5(a), each word in the 143 keywords is represented by a circle, and the frequency of occurrence of keywords is represented by the size of the circle. A connection line is generated when at least one of the two keywords connected to a keyword coexists. The different colors represented the 4 clusters: cluster 1 (in red) and cluster 2 (in green) mainly concentrated in mechanism research; cluster 3 (in yellow) focused on inflammation research; cluster 4 (in blue) focused on basic and clinical researches. As shown in Figure 5(b), based on the average publication year (APY), all keywords were divided into different colors with VOSviewer. Keywords in the recent six years were tumor microenvironment (2017.24), inflammasome (2017.03), autophagy (2016.33), and epithelial-mesenchymal transit (2016.11). Compared with Figures 5(a) and 5(b), the research of anti-inflammation for alleviating melanoma was relatively the latest. As shown in Figure 5(c), the top 7 clusters of keywords were “growth,” “transcription factor,” “rig i,” “metastatic melanoma,” “trail,” “cyclooxygenase 2,” and “reduced glutathione.” We found that “tumor necrosis factor” and “trail induced apoptosis” were with the highest burst strength (Figure 5(d)). Studies have shown that TNF-α treatment of melanoma can induce consistent dedifferentiation [30]. Furthermore, the latest keywords “therapy,” “inflammation,” “proliferation,” and “resistance” emerged in the last 6 years.Figure 5
Keyword analysis. (a) Visual cluster analysis of cooccurrence among keywords. (b) Timeline visualization of keywords. (c) Timeline distribution of the top 7 clusters. (d) Representative burst keywords with the strongest citation bursts.
(a)(b)(c)(d)


## 3.6. Cocitation Analysis

A cocitation relationship was constituted when two or more articles are simultaneously cited by more than one subsequent publication. The higher the cocitation number, the stronger the cocitation relationship, indicating that these articles have high similarity and will produce a common theme. We performed cluster analysis from the cocitation relationship analysis to further delineate the research frontier and obtain the publications with critical citations from a chronological perspective with CiteSpace and VOSviewer. Due to a large number of cited references, we set the minimum citations per reference as 20. Among the 103304 references which were cited by these publications, we selected 181 references for further analysis (Figure6(a)). There were 96 references in cluster 1 (in red), which mainly paid attention to drug therapy and mechanism of melanin. Cluster 2 (in green) mainly paid attention to study on various signaling pathways in cancer. Cluster 3 (in blue) focused on study of TNF-related apoptosis inducing ligand (TRAIL) and NF-κB in melanoma. The subject of cluster 4 (in yellow) was therapeutic effect and mechanism of betulinic acid on tumor. Furthermore, a visualized timeline of clusters was carried out (Figure 6(b)). We found that “NF-kappa B” and “EGF” are early fields in the study of NF-κB in melanoma. However, the current hotspots of NF-κB in melanoma are on “EMT,” “apoptosis,” and “duck.” Finally, a reference burst was conducted. Figure 6(c) shows the top 20 references that possessed the strongest citation bursts and the most representative references in terms of burst strength, burst duration, and burst time. The study of Griffith TS et al. (1998) possesses the highest bursts strength. The latest reference was the paper written by Hoesel B; in his article, he provided an overview that during cancer and inflammation, NF-kappa B and other signaling molecules had the most relevant modes of cooperativity and crosstalk. The top 10 cocited journals are shown in Table 5, and the most frequently cited journal is Cancer Res.Figure 6
Cocited reference analysis. (a) Visual cluster analysis of cooccurrence among cocited references. (b) Timeline distribution of the top 10 clusters. (c) Representative burst cocited references with the strongest citation bursts.
(a)(b)(c)Table 5
Top 10 cocited journals.
IdSourceCitationsTotal link strength1Cancer Research67966254922Journal Biological Chemistry65555899803Nature43234236034Proceedings of the National Academy of Sciences of the USA41394197715Oncogene39343621606Journal of Immunology38943613227Cell33573331828Science28512778449Clinical Cancer Research238322792010PloS One1779216877


## 3.7. Bibliographic Coupling Analysis

Bibliographic coupling refers to the phenomenon that two or more documents cite one document at the same time. Ranked by total link strength, top 10 authors in bibliographic coupling analysis were Richmond, A (7139), Fisher, Paul B. (5259), Ivanov, Vn (4723), Akira, Shizuo (4535), Richmond, Ann (4398), Sarkar, Devanand (4001), Ronai, Z. (3571), Zhang, Xu Dong (3178), Amiri, Ki (3150), and Colonna, Marco (3134). The top ten countries were the USA (228698), China (95306), Germany (75474), Italy (53416), Japan (52034), Australia (33843), South Korea (31695), Spain (29333), India (28982), and England (24595). The top 10 publications were Amiri (2005, 282), Almasan (2003, 270), Leblanc (2003, 254), Richmond (2002, 243), Raman (2007, 236), Soengas (2003, 230), Basseres (2006, 212), Cui (2014, 211), Kumar (2006, 209), and Gitlin (2006, 206). The top 10 affiliations were Vanderbilt Univ (19469), Univ Texas (14945) Columbia Univ (10203), Osaka Univ (10070), Univ Texas MD Anderson Canc Ctr (8976), Kyoto Univ (8676), NCI (7604), Harvard Univ (7121), Washington Univ (7079), and Dept Vet Affairs (6892). The top 10 journals were Oncogene (13026), Journal of Immunology (10892), Cancer Research (10041), Journal of Biological Chemistry (9912), Journal of Virology (8377), Clinical Cancer Research (7501), PloS One (6761), Cancer Biology & Therapy (4703), International Journal of Molecular Sciences (4573), and Journal of Investigative Dermatology (4529). Figure7 shows the bibliographic coupling analysis.Figure 7
Bibliographic coupling analysis. (a) Author cooccurrence. (b) Country cooccurrence. (c) Publication cooccurrence. (d) Affiliation cooccurrence. (e) Journal cooccurrence.
(a)(b)(c)(d)(e)


## 4. Discussion

Melanoma is a form of skin cancer that occurs in areas where there is little exposure to sunlight. Melanoma is mainly found in the back of men and the legs of women. This type of tumor develops from existing moles and it is usually irregular in shape and uneven at the edges. This type of skin cancer is a disease that can lead to fatal results depending on the stage of diagnosis. The five-year survival rate of patients with metastatic melanoma is less than 15%. Almost all organs are the target of metastasis. However, the liver, bones, and brain are most often affected. Local chemotherapy is becoming a promising strategy to avoid the sequelae of traditional treatment. Therefore, it is necessary to implement newly developed alternative therapies, such as the use of liposomes as drug carriers to prevent a variety of skin diseases [31].We conducted a bibliometrics analysis according to 2226 articles related to NF-κB in melanoma from the SCIE of WoSCC database during 2000–2021 with computational algorithm and multiple literature analysis software. Our work summed up research trends, hotspots, and frontiers for NF-κB in melanoma, and a summary of global research on its impact was obtained. Over the past 22 years, the annual number of publications fluctuates, but on the whole, it shows an upward trend, indicating its rapid development and constant research interest of NF-κB in melanoma. As for the top countries/regions, the USA ranked first in Np, indicating that the USA was a highly productive country on NF-κB in melanoma. In the top 10 authors, six authors came from the USA in the research of NF-κB in melanoma, suggesting that the USA has the most professional researchers in the world, and it explained why the USA developed rapidly in this field over the past 22 years. Compared with China, Japan had a moderately high Nc, although Japan’s Np is much lower than that of China. This showed that Chinese scholars and institutions should make more efforts on the quality of papers in this field. Notably, eight of the 10 most productive journals had higher IF. This means that publishing studies on NF-κB in melanoma in high-quality journals is not a challenge.Keyword analysis shows that the research of inflammation in melanoma is a research hotspot this year. There is increasing evidence that systemic inflammatory response is an important determinant of tumor progression and survival in many malignancies [32]. Several stages occur in the cellular process that transforms normal melanocytes into tumor cells. From benign nevus to mature tumor cells, genetic instability and proinflammatory environment can lead to tumorigenesis and metastasis. In the cellular microenvironment, immune cells and immune-related molecules play a decisive role in the inflammatory environment. Although the typical cell interface studied in tumors is between CTLS and cancer cells, the contribution of other immune cells is now widely recognized. These immune cells set up complex immune responses in cancer, including promoting tumors and promoting cancer progression. In some unpredictable situations, the clinical evolution of melanoma requires additional prognostic markers to identify patients at early stage and high risk of melanoma, thereby contributing to improved clinical surveillance strategies and treatment management. One of these additional biomarkers includes inflammatory immune cell infiltration that may describe local antitumor responses or may trigger protumor pathways [33]. Recent data suggest that secreted inflammatory cytokines play a paracrine role in the tumor microenvironment and also promote tumor growth. IL-1 expression stimulates angiogenesis and promotes tumor growth. During the evolution of melanoma, activated macrophages produce TGF-β (transforming growth factor-β), TNF-α (tumor necrosis factor-α), IL-1α (interleukin 1α), arachidonic acid metabolites, and extracellular proteases, while melanocytes express IL-8 and VEGF-α (vascular endothelial growth factor-α) and induce angiogenesis [34].Proliferation is another research hotspot in this field. Studies have shown that dendritic cells (DCS) are active molecules that indirectly resist the proliferation of melanoma cells. In addition, DC maturation, migration, and cross-initiation, as well as their functional interactions with cytotoxic T cells through immune checkpoint receptor ligands, are impaired. Many signals are transmitted by highly proliferating melanoma cells and helper cells as T cells, natural killer cells (NKs), tumor-associated macrophages (TAMs), T-regulatory cells (T-Regs), and myeloid suppressor cells (MDSCs), and endothelial cells contribute to the immunosuppressive environment. Results Phagocytosis of tolerance factors and interleukins (IL), such as IL-6 and IL-10. To highlight the role of immune infiltration in blocking melanoma progression, the composition, density, and distribution of cytotoxic T cells in the surrounding stroma have been described as predictors of response to immunotherapy [35]. In addition, NF-κB is an important pathway for melanoma to proliferate [36]. Punita Dhawan et al. reported that, through inhibitors of IKK, NF-κB could be suppressed and then inhibit the proliferation of melanoma cells [37]. The research of An’an XU suggested that inflammatory cytokines could activate NF-κB and induce the expression of proinflammatory cytokines, so accelerating the development of melanoma [38]. In recent years, although targeted therapy and immunotherapy have completely changed the treatment of metastatic melanoma, most patients have not been cured. Treatment of drug resistance remains a major clinical challenge. Melanoma includes cell subsets with different phenotypes, showing different genetic characteristics, leading to tumor heterogeneity and conducive to therapeutic resistance. Cellular plasticity in melanoma is called phenotypic transformation. Regardless of their genomic classification, melanoma will change from a proliferative and differentiated phenotype to an invasive, dedifferentiated, and usually treatment-resistant state [39]. Advances in the use of targeted therapy and immunotherapy have revolutionized the clinical management of melanoma patients, significantly prolonging their overall and progression-free survival. However, due to gene mutation and epigenetic modification, targeted therapy and immunotherapy are limited, which determines the huge heterogeneity and phenotypic plasticity of melanoma cells. Acquired resistance of melanoma patients to BRAF (brafi) and MEK (MEKI) inhibitors that block the mitogen-activated protein kinase (MAPK) pathway limits their long-term use. On the other hand, immune checkpoint inhibitors can only improve the prognosis of some patients, and the molecular mechanism of lack of response is being studied. Activating MAPK pathway through BRAF mutation may be a potential molecular target to overcome melanoma cells escaping immune surveillance.


## 5. Conclusion

In our study, a systematic view of the research hotspots, future directions, and evolutionary process of NF-κB in melanoma study was provided through bibliometrics analysis. It will help the younger generation of researchers who have just entered this field and experts who have been doing research in this field for a long time to better understand the current situation, trends, and future development hotspots of global research.



---

*Source: 3684228-2022-09-10.xml*