Natural Variants Of HBX And Clinical Phenotypes Analysis In Hepatocellular Carcinoma And Pericarcinoma Liver Tissues

Hepatocellular carcinoma (HCC) is reported to be one of the most common tumors worldwide. Annually newly emerged HCC cases and death cases are both approximately 700 thousand, half of which occur in China. Chronic hepatitis B virus (HBV) infection has been confirmed as an important pathological element for hepatocellular carcinoma. Evidence is accumulating that HBV X protein (HBx), the product of the fourth ORF, which is a multifunctional regulator could modulate transcription, intracellular signal transduction, malignant cell proliferation, apoptosis, protein degradation ubiquitination pathway, plays a significant role in HCC development. Lacking of precise rectification of the HBV polymerase results in a high percentage mutation during HBV replication, which inevitably causes many variants of X genes of hepatitis B virus between hepatocellular carcinoma(HCC) and pseudocarcino liver tissues(PCLT).In our study, we have examined 287 hepatocellular carcinoma and 205 pericarcinoma liver tissues. After DNA extraction, polymerase chain reaction (PCR) and sequencing, we obtain 169 sequences from hepatocellular carcinoma and 117 sequences from pericarcinoma liver tissues. Mutations of deletion, insertion, substitution and truncation are occurd in both hepatocellular carcinoma and pericarcinoma liver tissues.Matched Medical records of sequenced samples are reviewed and processed stratified analysis. C-truncation was found to have a significant higher percentage in HCC than PHLT (χ2=4.23, P=0.040)and this trend even more remarkable when take cirrhosis into consideration (χ2=4.59, P=0.032).Percentage of mutation of insertion is similar in HCC and PCLT, but many kinds were found for the first time, and mutation of insetion only found in AFP positive group(AFP>20ng/ml) (χ2=10.12 P=0.006).Single site mutation is common and interlaced, there is no single site mutation of nucleic acid or amino acid makes distribution discrepancy between HCC and PCLT. When stratified for gender, site 43,47,127,131,132 make distribution discrepancy in male between HCC and PCLT, most of these sites related to hydrophilic/lyophobic character of amino acid. Site 40 makes significant discrepancy between HCC and PHLT related to hydrophilic/lyophobic character of amino acid in both male and female(χ=5.04, P=0.033).Site 47 makes significant discrepancy among clinical stage Ⅰ Ⅱ Ⅲ related to hydrophilic/lyophobic character of amino acid(χ2=7.00, P=0.030), percentage of lyophobic amino acid is increasing in the progression of clinical stages. Notablely, opposite trend occour in the site 127(χ2=12.64,P=0.001).Site 132 makes significant discrepancy(χ2=4.06, P=0.044) related to hydrophilic/lyophobic character of amino acid and significant discrepancy(χ2=7.79, P=0.020)when related to differentiation stage in male and (χ2=8.28,P=0.004)when related to HBsAg+/-.We concluded that mutations of deletion, insertion, substitution and truncation are closely bound up with HCC development.