SN: Conception, design, experimental work, and acquiring data from array analysis. MH: Experimental work. MH: Analyzing data and experimental

work. MK: Experimental work. YN: Experimental work. ST: Sample collection. HS: Sample collection. TF: Sample collection SY: Sample collection. YK: Sample collection. All authors read and approved the final manuscript.”
“Background Hepatitis B (HBV) or C virus (HCV) infection and alcohol consumption are leading causes of hepatocellular carcinoma (HCC) that predominantly develops from chronic hepatitis and cirrhosis [1]. Among the numerous genetic and epigenetic defects associated with carcinogenesis [2], telomere abnormalities check details play a role in tumor promotion and maintenance [3–9]. Telomeres, the chromosome extremities, are elongated by the human telomerase, the catalytic moiety of which is encoded by the human telomerase reverse transcriptase (hTERT) gene [10]. Additionally, telomeres are protected by specific proteins, click here the shelterin complex [11] and by additional non-specific factors such as human meiotic recombination 11 homolog A and B (hMRE11A and B), Ku proteins 70 and 80 (Ku70 and Ku80), Nijmegen breakage syndrome-1 (NBS1), RAD50, tankyrase 1 and 2 (TANK1 and 2), Werner syndrome helicase (WRN), and PIN2/TRF1-interacting,

telomerase inhibitor 1 (PINX1) [12]. These factors prevent telomere degradation and facilitate telomerase-based telomere elongation. Short or unprotected telomeres are recombinogenic and can therefore promote tumorigenesis [3]. In normal cells, dysfunctional telomeres trigger the DNA damage response and replicative cellular senescence [10, 13–18]. Early oncogenic events frequently involve evasion of the DNA damage response, which

allows the clonal persistence of cells bearing a telomere-associated genetic instability. During early tumor development, hTERT is frequently expressed and allows the clone to bypass mitotic catastrophe and replicative senescence, contributing to malignant immortalization [4, 5, 19–21]. Therefore, impaired telomere protection and/or elongation represent putative oncogenic events. Indeed, numerous oncogenes or tumor suppressor genes have been reported to interfere with the telomere machinery. In the liver, telomere shortening correlates with Nintedanib (BIBF 1120) chromosomal instability and the development of HCC [4, 6, 8]. Hepatotropic viruses and alcohol have been reported to interfere with telomere homeostasis. For example, hTERT transcription was found to be activated upon HBV DNA integration in the vicinity of the hTERT gene [22] while HBV encoded X (HBx) [23–27] or preS2 [28, 29] proteins promote hTERT expression and contributed to clonal persistence. However, some mutated HBx have been reported to possess repressive effects on hTERT transcription [25]. The HCV core protein has been demonstrated to enhance telomerase activity [30] while alcohol exposure triggers premature senescence with accelerated telomere shortening [31].