bluuebunny/crossref_metadata_2025_split huggingface dataset:
Novel and existing mutations in the EGF receptor tyrosine kinase domain are predictors of optimal resectability (OR) in malignant peritoneal mesothelioma (MPM)
Authors: Foster J. M. , Gatalica Z. , Lilleberg S. , Haynatzki G. , Loggie B. W. 
Published: March 2020

10503 Background: MPMs represent 20% of all malignant mesothelioma (MM) cases. The median survival for these tumors is less than a year, and like other peritoneal tumors this is due to intra-abdominal recurrence/progression. Currently there is a paucity of information about the biology of these tumors and molecular perturbations that are involved in tumor formation. Elucidation of mutations and biological pathways active in these tumors may identify valuable prognostic markers, as well as facilitate the development of novel therapies. Methods: Twenty-nine MPM patients were evaluated at a single tertiary center and their tumors were probed for mutations in the catalytic TK domain of EGF receptor (mut+). All specimens were examined for somatic mutations by PCR amplification. Twenty-five patients were treated with cytoreductive surgery (CRS) ± IPHC and complete clinical data including age, sex, cytoreductive score, histology, mutation, and survival was available for comparison of the mut+ and mut- groups. Results: The median age was 56, and 71% of the patients were male with a median follow-up time (MFT) of 14.5 months. Mutations were found in 31% (9/29) of the tumors, 7 of these mutations were novel, and the 8th one was the L858R mutation described in NSCLC. Of the 25 patients managed surgically there were 7 mut+ and 18 mut- ( Table ). OR (=R2a) was achieved in 7/7 (100%) of mut+ group and 9/18 (50%) mut- (p=.03). All mut+ are alive with a MFT of 24 months, while 5/18 (28%) of the mut- group are DOD with a MFT of 7 months (p=.27). In an ANCOVA model OR (p=0.04) was found to be predictive of survival. Conclusions: The EGFR-TK appears to be a common site for mutation in MPM, with the identification of novel and known activation mutation in 31% of tumors. Mut+ was predictive of OR. OR was predictive of survival in short term follow-up, and with longer follow-up, mut+ may be predictive of survival as well as represent a subset of patients who may be responsive to TK-inhibitors therapy. [Table: see text] No significant financial relationships to disclose.
TROP2 is a major determinant of growth and metastatic spreading of human cancer
Authors: Alberti S. , Trerotola M. , Vacca G. , Zappacosta R. , Rossi C. , Guerra E. , Bonasera V. , Lasorda R. , Lattanzio R. , Piantelli M. 
Published: March 2020

10510 Background: The TROP2 gene encodes a transmembrane calcium signal transducer, involved in the regulation of cell- cell adhesion. Methods: To identify the role of Trop-2 in transformed cells, we studied its expression pattern and function by DNA array and SAGE analysis, Northern and Western blotting, flow cytometry, confocal microscopy and IHC in experimental systems and in man. Overexpression or down-regulation of Trop-2 and directed mutagenesis were used to identify its role in tumor growth and metastasis in vivo. Results: DNA microarray, EST, SAGE, RT-PCR and Northern blot analysis of human tumors revealed expression of the TROP2 gene in most cancers. IHC analysis of human tumors (1755 cases) revealed a corresponding overexpression of Trop-2 protein. Trop-2 potently stimulated the growth of tumor cells, whereas TROP2 siRNA inhibited it. Deletion of the cytoplasmic region of Trop-2 abolished the growth stimulatory capacity, as did mutagenesis of the S303 PKC phosphorylation site. Proteomic analysis showed that multiple PKC isoforms partecipate to the Trop-2 signaling network. In vivo imaging showed dynamic colocalization of PKCs and Trop-2 in vivo in membrane ruffles and podosomes. DN PKCs and siRNA abolished Trop-2-induced growth. Strikingly, comparative global gene expression analysis revealed that TROP2 was the only gene up-regulated across different metastatic models, tumor types and animal species. IHC analysis revealed a dramatic up-regulation in metastases from colon, stomach, breast and ovary tumors in man. To assess if Trop-2 may play a causal role in metastatic spreading, TROP2-transfected KM12SM colon cancer cells were orthotopically injected in nude mice. TROP2-overexpressing transfectants demonstrated increased metastatic potential to the liver. Deletion of the HIKE domain of Trop-2 severely diminished, whereas that of the whole cytoplasmic region vastly increased metastatic diffusion, indicating the existence of both metastatic enhancers and silencers in the Trop-2 cytoplasmic tail. Conclusions: Our findings demonstrate that Trop-2 is a novel, widespread, stimulator of human cancer growth and a unique marker and causal factor of metastatic cancer, and candidate Trop-2 as a target of novel diagnostic and therapeutic procedures. No significant financial relationships to disclose.
Differential response to primary chemotherapy and long-term survival in patients with triple-negative breast cancer
Authors: Liedtke C. , Mazouni C. , Hess K. R. , Tordai A. , André F. , Symmans W. F. , Gonzalez-Angulo A. M. , Green M. , Hortobagyi G. N. , Pusztai L. 
Published: March 2020

10519 Objective. Triple-negative breast cancer is defined as a subtype of invasive breast cancer which lacks estrogen and progesterone receptor expression as well as HER2/neu expression and is highly similar to the basal-like subtype defined by gene expression profiling. Method. 1,143 patients treated at MD Anderson Cancer Center in neoadjuvant trials were included in a retrospective comparative analysis between triple-negative tumors and non-triple-negative tumors for response to neoadjuvant chemotherapy as well as long- term survival. Results. 827/1,143 (72%) patients had received taxanes, either as a single-agent (n=60) or in combination with anthracycline (n=767), whereas the remainder patients received an anthracycline-only chemotherapy. Overall 258/1,143 (23%) tumors were triple- negative. Complete pathological response (pCR) was achieved in 63/257 (25%) patients with triple-negative tumors compared to 99/888 (11%) in patients with non-triple-negative tumors (odds ratio [OR] 1.14, 95%CI: 1.09–1.20, p=.0082). Triple-negative status correlated significantly with high nuclear grade (p<.0001), whereas no significant correlation with any established clinicopathologic parameter was observed. However, 5-year overall survival (5yrOS) was 66% in the triple-negative group compared to 83% in the non-triple-negative control group (OR 2.1, 95%CI: 1.6–2.8, p<.0001). In multivariate analyses, triple-negative status (hazard ratio [HR] 2.0, 95%CI: 1.4–2.8, p<.0001), high nuclear grade, increased tumor size (HR 1.5, 95%CI: 1.3–1.8, p<.0001), positive nodal status (HR 1.4, 95%CI: 1.2–1.7, p=.0002) and high nuclear grade (HR 1.7, 95%CI: 1.1- 2.4, p=.0089) were significantly associated with decreased 5yrOS. When survival was analyzed according to both response rate and triple negative status, achievement of pCR was a stronger predictor of survival compared to triple-negative status. Conclusion. Triple- negative expression status among patients with breast cancer constitutes an independent unfavorable prognostic factor with regards to overall survival unless achieving pCR after neoadjuvant chemotherapy. No significant financial relationships to disclose.
BRAF mutation predicts MEK-dependence in non-small cell lung cancer (NSCLC)
Authors: Pratilas C. A. , Halilovic E. , Sawai A. , Grbovic-Huezo O. , Rosen N. , Solit D. B. 
Published: March 2020

10523 Background: Constitutive ERK signaling is common in human cancer and is often the result of activating mutations in BRAF, RAS and upstream receptors. Missense BRAF kinase domain mutations are frequently observed in melanoma, colon and thyroid cancers and less frequently in lung and other cancer types. The vast majority (>90%) involve a glutamic acid for valine substitution at codon 600 (V600E), which results in elevated BRAF kinase activity. BRAF kinase domain mutations with intermediate and impaired kinase activity have also been identified, most frequently in NSCLC. We have previously reported that tumors with V600E BRAF mutation are selectively sensitive to MEK inhibition. Methods: Using the potent and selective MEK1/2 inhibitor PD0325901 (Pfizer), we examined a panel of NSCLC cell lines with mutant EGFR, KRAS, and/or low, intermediate and high-activity BRAF kinase domain mutations, with regard to MEK dependence. In all but one case, EGFR, KRAS and BRAF mutations were mutually exclusive. Results: Consistent with our prior results, NSCLC cells with V600E BRAF mutation were exquisitely sensitive to MEK inhibition (PD0325901 IC50 of 2nM). The proliferation of cells with non-V600E mutations, including those with high (G469A), intermediate (L597V) and impaired (G466V) kinase activities, was also MEK dependent with IC50's ranging between 2.7 and 80 nM. Inhibition of MEK in these cells resulted in downregulation of cyclin D1 and G1 growth arrest, with variable induction of apoptosis. Despite high basal ERK activity, NSCLC tumor cells with EGFR mutation were uniformly resistant to MEK inhibition (at doses of up to 500nM), despite effective inhibition of ERK phosphorylation. Tumor cells with RAS mutation had a more variable response, with some cell lines demonstrating sensitivity, while others were completely resistant. There was no correlation between basal ERK activity and sensitivity to MEK inhibition. A strong inverse correlation between AKT phosphorylation/ activity and PD0325901 sensitivity was observed. Conclusions: These results suggest that MEK inhibition may be useful therapeutically in tumors with V600E and non-V600E BRAF kinase domain mutations. The results also suggest that inhibition of both MEK and AKT signaling may be required in NSCLC tumors with high basal AKT activity. No significant financial relationships to disclose.
Microsatellite instability (MSI) due to mutation or epigenetic silencing is associated with increased cytotoxicity to irinotecan (CPT-11) in human colorectal cancer (CRC) cell lines
Authors: Vilar E. , Scaltriti M. , Saura C. , Guzman M. , Macarulla T. , Arribas J. , Tabernero J. 
Published: March 2020

10527 Background: MSI is a phenomenon found in tumor DNA of individuals with dysfunction of the mismatch repair system (MMR). Epigenetic inactivation by promoter hypermethylation of hMLH1 causes 15 to 20% of sporadic CRC. In vitro studies have suggested an increased sensitivity to CPT-11 of MMR-deficient human CRC cell lines. Chemosensitivity evaluation in preclinical models of human CRC cell lines according to the MMR status could help in the design of specific studies in the clinical setting. Methods: We have performed drug cytotoxicity assays to compare sensitivity to CPT-11 in several human CRC cell lines with different MMR gene status that resemble the most common clinical situations in CRC patients. HCT116, HCT15, SW48 and RKO are MSI-High (MSI-H), being HCT116 due to a homozygous nonsense mutation of hMLH1 gene, HCT15 due to MSH6 mutation (both of them similar to hereditary cases) and both SW48 and RKO due to methylation of hMLH1 promoter (as MSI-H sporadic CRC cases). HT29 expresses normal levels of MMR proteins (as microsatellite stable (MSS) CRC cases). Drug concentrations resulting in 50% growth inhibition (IC50) were determined by a curve-fitting analysis and cell cycle analyses in order to characterize the cytotoxicity of cell lines were performed. Results: IC50 values and 95% confidence intervals (CI) are show in Table 1 . hMLH1-deficient cell lines due to either epigenetic silencing or mutation showed very similar IC50 and were 5- to 8-fold more sensitive to CPT-11 than the MSS line. hMSH6- deficient cell line HCT15 has sensitivity closer to MSS than MSI cell lines. Treatment with CPT-11 induced a G2/M arrest. Conclusions: Lack of hMLH1 protein due to either genetic alteration or epigenetic silencing correlates with increased sensitivity to CPT-11. MSI-H CRC cell lines are more sensitive to CPT-11 than MSS. Future clinical trials tailoring chemotherapy regimens based on microsatellite status are warranted. [Table: see text] No significant financial relationships to disclose.
Mutations in the proapoptotic BAX gene are associated with defective DNA mismatch repair and altered tumor growth rates in human colon cancers
Authors: Sinicrope F. , Rego R. L. , French A. J. , Foster N. R. , Sargent D. J. , Windschitl H. , O'Connell M. J. , Thibodeau S. N. 
Published: March 2020

10529 Background: BAX mutations are associated with defective DNA mismatch repair (MMR) in human colon cancers. However, the impact of BAX inactivation upon tumor cell apoptosis and proliferation in vivo remain unknown. We analyzed and compared caspase-3 and Ki-67 expression in tumors with and without BAX mutations. Methods: TNM stage II and III (n= 377) colon carcinomas were studied from participants in a 5-FU-based adjuvant therapy trial. Archival tumors were analyzed for instability at the BAT26 mononucleotide locus using polymerase chain reaction and hMLH1, hMSH2 and hMSH6 by immunohistochemistry (IHC). Frameshift mutations in a tract of eight deoxyguanosines within BAX were analyzed. Expression of caspase-3 and Ki-67 proteins were analyzed by IHC. Results: Thirty-nine of 377 (10%) tumors showed defective MMR defined as instability at BAT26 and loss of either hMLH1, hMSH2 and/or hMSH6 proteins. BAX mutations were found in 20 of 37 (54%) MMR deficient tumors and in 1 of 50 (2%) tumors with intact MMR. Mean and median number of caspase-3-positive cells were increased in tumors with defective MMR (p= 0.04), but did not differ based upon BAX status [ Table ]. However, tumors with BAX mutations showed higher Ki-67 labeling indices compared to those with wild type BAX (p= 0.01)[ Table ]. Neither BAX mutations nor caspase-3- positive cells were prognostic in a univariate analysis. Tumors with lower Ki-67 extent had improved overall survival (p=0.06), but not DFS (p=0.24). Defective MMR (vs intact) was associated with better DFS in a multivariate analysis (p= 0.03). Conclusion: MMR deficient colon cancers show frequent BAX inactivation, yet have increased apoptotic rates as indicated by increased caspase-3 expressing tumor cells. BAX mutation was associated with hyperproliferation suggesting a growth advantage compared to wild type tumors. [Table: see text] No significant financial relationships to disclose.
The tyrosine kinase src plays a crucial role in leukemic cell proliferation in AML
Authors: Schuch G. , Schäfer E. , Eggert K. , Loges S. , Görn M. , Laack E. , Bokemeyer C. , Fiedler W. 
Published: March 2020

10531 Background: Src-family tyrosine kinases are known to be involved in signal transduction pathways of growth factors and cytokines in hematopoetic cells. While the role of other src family members has been studied widely, only few data exist about c-src in leukemia. The actual study was performed to analyze src mutations in leukemic cells and to determine the role of pp60src in leukemic cell proliferation. Methods: AML cell lines and primary samples were analyzed for expression and activation of src by RT-PCR and Western blot analyses. Mutational analyses were performed by sequencing of C-terminal cDNA from 60 AML samples. The effects of src inhibition were studied by src-specific inhibitors PP1 and PP2 or by siRNA transfection. Effetcs of src inhibition were monitored in proliferation assays and analyzes of signalling through Erk1/2 and apoptosis by annexin V staining and DNA laddering. Results: In all 60 patients analyzed expression of c-src mRNA was detected by RT-PCR. Western blot analyses confirmed strong expression of src on the protein level and revealed a robust activation of the protein as determined by tyrosine phosphorylation. Incubation of leukemic cells with PP1 and PP2 caused significant inhibition of proliferation in a dose dependent manner. Similar results were observed after transfection with specific siRNAs. Src inhibition blocked phosphorylation of pp60src, Erk1/2 and induced apoptosis in leukemic cells. Mutational analyses as performed by SSCP/heteroduplex and bi-directionally sequencing revealed wildtype sequence in cell lines and 60 clinical samples. Conclusions: In summary, pp60src is highly expressed and activated in cell lines and clinical samples of human AML. Moreover, phosphorylation of src is essential for leukemic cell proliferation. Underlying mutations in the coding sequence of c-src causing constitutive activation could be excluded. These data suggest that pp60src plays a crucial role in AML and src inhibition by targeted therapy might offer a useful new approach in the treatment of AML. No significant financial relationships to disclose.
Clinical relevance of circulating CK-19 mRNA-positive cells detected during the period of adjuvant tamoxifen treatment in patients with early breast cancer
Authors: Xenidis N. , Markos V. , Apostolaki S. , Perraki M. , Pallis A. , Sfakiotaki G. , Kafousi M. , Stathopoulos E. , Kakolyris S. , Mavroudis D. , Georgoulias V. 
Published: March 2020

10534 Background: To evaluate the effect of adjuvant treatment with tamoxifen on the CK-19 mRNA+ circulating tumor cells (CTCs) in patients with early-stage breast cancer. Methods: CTCs were prospectively and longitudinally detected using a specific real-time PCR for CK-19 mRNA in 119 patients with estrogen and/or progesterone receptor-positive tumors during the period of tamoxifen administration. Results: Twenty-two (18.5%) patients had detectable CK-19 mRNA+ CTCs after the completion of adjuvant chemotherapy and in 15 (68.2%) of them adjuvant tamoxifen could not eliminate these cells (persistently positive). In 68 (57.1%) patients no CK-19 mRNA+ CTCs could be detected throughout the follow up period (persistently negative). Seven (46.7%) of the 15 persistently positive and six (8.8%) of the 68 persistently negative patients developed disease recurrence (p=0.00026). Persistence of CK-19 mRNA+ CTCs was associated with a significantly shorter median disease-free interval (p=0.0001) and overall survival (0.0005). Multivariate analysis revealed that the detection of CK-19 mRNA+ CTCs during the administration of tamoxifen was associated with an increased risk of relapse (HR=22.318, p=0.00006) and death (HR=13.954, p< 0.00001). Conclusions: The detection of CK-19 mRNA+ CTCs throughout the period of adjuvant tamoxifen treatment is an independent poor prognostic factor in patients with early breast cancer. No significant financial relationships to disclose.
Predicting breast cancer risk in BRCA1 and BRCA2 carriers: Methylation studies using intraductal fluid
Authors: Antill Y. C. , Mitchell G. , Johnson S. A. , Devereux L. , Milner A. , Sridhar A. , Kirk J. A. , Phillips K. , Lindeman G. , Campbell I. G. 
Published: March 2020

10537 Background: Genomic alterations are likely to precede the phenotypic changes of breast cancer (BC) and include hyper- methylation of tumour suppressor genes. An intraductal approach, such as ductal lavage (DL), is an attractive means of accessing ductal epithelial and other cells in a prospective fashion. Methods: Women with at least one breast unaffected by BC, with a germline BRCA1 or BRCA2 mutation, attended for 6-monthly DL collection for up to 3 years. Standard methods were used for DNA extraction and bisulfite conversion. Hyper-methylation of p16, RASSF1A, twist and RARβ genes was investigated using a qualitative, real-time, nested PCR assay. Associations between methylation status and categorical variables were tested using Fisher's exact test including cytological findings and BC incidence. Logistic regression was used to examine the relationship between methylation status and patient age, and to examine the effects of multiple variables. Analyses were performed at three levels; samples from a single breast over time and from a single duct over time and each sample in isolation. Results: A total of 173 DL samples from 98 ducts in 56 breasts were analysed in 34 women (16 BRCA1 and 18 BRCA2 mutation carriers) with a median age of 43 years (range 27- 60). DL fluid was collected from all women on at least one occasion (median 2.5 visits, range 1–5). Five women developed BC on study. Methylation of p16 was strongly associated with a known BRCA1 mutation (p=0.0003, p<0.0001 and p<0.0001 at the breast, duct and sample levels respectively) and was also more likely in women with a previous history of contralateral BC (p=0.0008 and p<0.0001 at the duct and sample level respectively). Independent associations were seen for women who developed BC on study and methylation of p16 and RASSF1A (p16: p=0.0023 at the sample level only) and (RASSF1A: p=0.0760, p=0.0178 and p<0.0001- at the breast, duct and sample level respectively). Conclusions: The methylation pattern in a panel of genes could be used as a biomarker for risk of future breast cancer. In addition p16 methylation may be a predictor of BRCA1 mutation status. Further research is required to corroborate these findings as the numbers recruited for this study are small with a short duration of clinical follow up. No significant financial relationships to disclose.
Detection of distant metastases in breast cancer patients: Comparison between [18F]-fluorodeoxyglucose positron emission tomography and conventional imaging
Authors: Mahner S. , Schirrmacher S. , Müller V. , Habermann C. , Brenner W. , Schwarz J. Dose 
Published: March 2020

1054 Background: The presence of distant metastases is a key prognostic factor in breast cancer patients and plays a central role in therapeutic decisions. To detect distant metastases, chest X-ray, abdominal ultrasound and bone scintigraphy are performed as standard of care in many centers. In various tumors, [18F]fluorodeoxyglucose positron emission tomography (FDG-PET) detects metastatic disease with high accuracy, but the diagnostic value in breast cancer still needs to be defined. The aim of this study was to compare the diagnostic performance of FDG-PET with conventional imaging. Methods: In 119 breast cancer patients who presented for restaging, whole-body FDG-PET was compared with chest X-ray, bone scintigraphy and abdominal ultrasound. Each imaging modality was independently assessed and classified as ‘negative’, ‘equivocal’ and ‘positive’ for metastasis. The imaging results were compared with histopathology and clinical follow-up including follow-up imaging procedures which together served as the reference standard. Results: For findings classified as ‘positive’, FDG-PET detected distant metastases with a sensitivity of 87% and a specificity of 83%. In contrast, the sensitivity and specificity of combined conventional imaging procedures was 43% and 98%, respectively. The positive and negative predictive values were 89% and 82% for FDG-PET and 96% and 69% for conventional imaging. Combining ‘equivocal’ and ‘positive’ results, the sensitivity and specificity of FDG-PET was 93% and 76%, respectively, compared to 61% and 86% for conventional imaging. The positive and negative predictive values were 86% and 88% for FDG-PET versus 77% and 75% for conventional imaging. Conclusions: FDG-PET is superior to conventional imaging procedures for detection of distant breast cancer metastases. However, the use of computed tomography (CT), particularly in combined PET/CT, needs to be addressed in future studies comparing anatomical vs. metabolic staging procedures in breast cancer patients. No significant financial relationships to disclose.