Experimental Study Of The Association Between Chromosome Telomere Length And The Risk And Prognosis Of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is seriously harmful to human health for its hidden, rapid progression, and lack of effective treatment. Therefore, it is important to search for effective screening and prognostic markers by exploring the molecular mechanism of hepatocarcinogenesis and progression combining with clinical data analyses of patients.The alteration of telomere length is involved in hepatocarcinogenesis and progression. Besides of environment factors such as viruses'infection, alcohol use, aflatoxin, smoking and drug, increasing studies have been focusing on the role of genetic predisposing factors in hepatocarcinogenesis and progression. Previous studies have suggested that the alteration of telomere length is associated with development and progression of many tumors, and especially that leukocyte relative telomere length may be a potential biomarker for prediction of cancer risk and prognosis. In addition, several studies have demonstrated that telomere length is shortening in liver cirrhosis, adjacent and tumor tissues, indicating that telomere length is involved in hepatocarcinogenesis and progression. However, the relationship between leukocyte relative telomere length and hepatocarcinogenesis and progression is undermined. Our study explored the role of leukocyte telomere length in the development and progression of hepatocellular carcinoma, and preliminarily assessed its role in prevention, early screening, and prognostic prediction of liver cancer.Part 1: Study of the association between chromosome telomere length and HCC riskThis study was a case-control study with 3 groups, including 240 HBV related HCC paitents as the case group, 120 paitents with HBV related chronic liver diseases (CLD) as the CLD control, and 240 healthy participants as the healthy control. Blood samples of 3 groups and related epideimiological data were collected, genomic DNA of each blood sample were obtained with high quality, and then relative telomere length (RTL) of each individual was determined using real-time polymerase chain reaction (PCR). Our data showed that leukocyte telomere length of HCC cases was significantly longer than CLD controls or healthy controls; Compared with individuals who had short RTL, individuals who had long RTL had a significantly increased risk of HCC when either healthy controls [adjusted OR (95% CI): 7.28 (4.46-11.8)] or CLD controls [adjusted OR (95% CI): 2.86 (1.74-4.70)] were used as the reference group. A significant dose-response relation was observed between HCC risk and long RTL (P trend < .001 for both control groups). In addition, there was a significantly positive RTL correlation between blood and normal liver tissues (r = 0.78; P < .001) or cirrhotic liver tissues (r = 0.67; P = .001). Furthermore, a significant joint effect on the risk of HCC was noted between RTL and smoking status or alcohol use. Part 2: Study of the association between chromosome telomere length and HCC prognosis228 incident patients with primary HCC were recruited into this study, blood sample and demographic and clinic data of each HCC patient were collected. Genomic DNA of each blood sample was obtained and RTL was determined using real-time PCR. 20 patients were excluded due to incomplete clinical or follow-up information, and 6 patients were excluded due to poor DNA quality. Finally, 202 HCC patients were included and successfully assayed. Multivariate Cox regression analysis revealed that longer leukocyte RTL was significantly associated with worse HCC survival [HR (95% CI): 2.18 (1.41– 3.35); P < 0.001]. Additionally, RTL, Child-Pugh score, tumor size, portal vein thrombus (PVT) and alpha-fetoprotein (AFP) were independent predictors for overall survival of HCC patients. Analysis stratified by host characteristics showed that longer leukocyte RLT was significantly associated with worse prognosis of HCC patients especially those with with adavanced diseases, such as liver cirrhosis, bigger tumor size, multiple tumor numbers, higher AFP level, and higher TNM stage. Kaplan-Meier analysis showed that the median survival time (MST) of patients with longer RTL was significantly shorter than MST of patients with shorter RTL (P = 0.002) and significant results were obtained in the subgroups with adavanced diseases. In conclusion, our study firstly demonstrated that longer leukocyte RTL could predict the worse survival of HCC patients as a potential biomarker.