TERT promoter mutation during development of hepatoblastoma to hepatocellular carcinoma
Authors: Rui Dong, Shan Zheng, Kuiran Dong
Journal: Journal of Hepatology (2014)

The genomic landscape of hepatoblastoma and their progenies with HCC-like featuresJournal of HepatologyVol. 61Issue 6PreviewHepatoblastoma (HB) is the most common childhood liver cancer and occasionally presents with histological and clinical features reminiscent of hepatocellular carcinoma (HCC). Identification of molecular mechanisms that drive the neoplastic continuation towards more aggressive HCC phenotypes may help to guide the new stage of targeted therapies. Full-Text PDF Reply to: "TERT promoter mutation during development of hepatoblastoma to hepatocellular carcinoma"Journal of HepatologyVol. 62Issue 2PreviewWith interest we read the letter by Dong et al., bringing up important points on the role of telomerase reverse-transcriptase (TERT) promoter mutations in paediatric liver tumours, which we would like to comment. Full-Text PDF Open Access We read with great interest the article by Eichenmüller et al. [[1]Eichenmüller M. Trippel F. Kreuder M. Beck A. Schwarzmayr T. Häberle B. et al.The genomic landscape of hepatoblastoma and their progenies with HCC-like features.J Hepatol. 2014; 61: 1202-1204Abstract Full Text Full Text PDF PubMed Scopus (154) Google Scholar], who used whole-exome sequencing to describe the genomic landscape of hepatoblastoma (HB) cells and their progenies with hepatocellular carcinoma (HCC)-like features. They concluded that mutation of CTNNB1 and activation of the NFE2L2-KEAP1 pathway are important features in HB-development and further define loss of genomic stability and TERT promoter mutations as prominent characteristics of aggressive HB with HCC features. Although we appreciate these impressive findings, there are some important considerations that need to be stressed. First, HB and HCC share a common CTNNB1 mutation, which leads to activation of Wnt signalling and the genesis of liver cancer in both adults and children. The oncogene TERT has been shown to regulate CTNNB1 expression, while conversely β-catenin can bind to the TERT promoter to positively influence TERT expression [2Hoffmeyer K. Raggioli A. Rudloff S. Anton R. Hierholzer A. Del Valle I. et al.Wnt/beta-catenin signaling regulates telomerase in stem cells and cancer cells.Science. 2012; 336: 1549-1554Crossref PubMed Scopus (413) Google Scholar, 3Park J.I. Venteicher A.S. Hong J.Y. Choi J. Jun S. Shkreli M. et al.Telomerase modulates Wnt signalling by association with target gene chromatin.Nature. 2009; 460: 66-72Crossref PubMed Scopus (529) Google Scholar]. TERT promoter mutations are commonly involved in the last step of malignant transformation in association with CTNNB1 mutations in HCC [[4]Nault J.C. Mallet M. Pilati C. Calderaro J. Bioulac-Sage P. Laurent C. et al.High frequency of telomerase reverse-transcriptase promoter somatic mutations in hepatocellular carcinoma and preneoplastic lesions.Nat Commun. 2013; 4: 2218Crossref PubMed Scopus (442) Google Scholar]. Eichenmüller et al. showed that the expression of TERT was upregulated in both HB and transitional liver cell tumours (TLCT). However, TERT promoter mutations were identified in two thirds of TLCTs analysed but not in any instances of HB. They concluded that the TERT promoter mutation is a selective phenomenon for advanced HB with HCC-like features. However, only three patients were included as TLCT controls, and the cause(s) of their disease were not specified. Moreover, one of the TLCT controls did not possess mutations of the TERT promoter. This limited incidence of TLCT may influence the conclusion that TLCT is a genetically derailed progeny of HB. Analysis of TERT promoter mutations in paediatric HCC may assist in making such a conclusion more convincing. Second, it has been recently reported that the TERT promoter mutation is an early event in liver carcinogenesis of cirrhosis, based upon analysis of the sequence of lesions from cirrhosis to low-grade dysplastic nodules (LGDN), high-grade dysplastic nodules (HGDN), early HCC (eHCC) and small and progressed HCC. TERT promoter mutations occurred in a small proportion of dysplastic nodules (6% of LGDN and 19% of HGDN), and the prevalence increased with the degree of dysplasia. The prevalence of TERT promoter mutations was dramatically increased in eHCC (61%), suggesting a molecular shift had occurred following development of eHCC [[5]Nault J.C. Calderaro J. Tommaso L.D. Balabaud C. Zafrani E.S. Bioulac-Sage P. et al.TERT promoter mutation is an early somatic genetic alteration in the transformation of premalignant nodules in hepatocellular carcinoma on cirrhosis.Hepatology. 2014; (Epub ahead of print)https://doi.org/10.1002/hep.27372Crossref Scopus (218) Google Scholar]. These findings suggest that TERT promoter mutations might be an important mechanism to drive malignant liver cells towards a more aggressive eHCC-like phenotype. TERT promoter mutations may therefore be a selective phenomenon of advanced HB with eHCC-like features. Furthermore, TERT promoter mutations were significantly associated with histological (pseudoglandular formation, cytological atypias, and unpaired arteries) and immunohistochemical (positive staining for GPC3 and HSP70) features of malignancy [[5]Nault J.C. Calderaro J. Tommaso L.D. Balabaud C. Zafrani E.S. Bioulac-Sage P. et al.TERT promoter mutation is an early somatic genetic alteration in the transformation of premalignant nodules in hepatocellular carcinoma on cirrhosis.Hepatology. 2014; (Epub ahead of print)https://doi.org/10.1002/hep.27372Crossref Scopus (218) Google Scholar]. Therefore, Eichenmüller et al. should further evaluate their data by examining paediatric HCC patient samples for the aforementioned histological and immunohistochemical features. Alternatively, a larger case-control study that incorporates the above-mentioned points is required. The authors declared that they do not have anything to disclose regarding funding or conflict of interest with respect to this manuscript.