Abstract: Objective To explore genetic changes on chromosome 13 and particularly expression of the RB1 anti-oncogene，located on 13q14.2，in hepatocellular carcinoma（HCC） in patients exposed to both hepatitis B virus（HBV） and aflatoxin B₁（AFB₁）. Methods Thirty-two HCC tissue samples were divided into four subgroups according to HBV and AFB₁ exposure：group A（n=10），HBV（+）/AFB₁（+）；group B（n=10），HBV（+）/AFB₁（-）；group C（n=6），HBV（-）/AFB₁（+）；group D（n=6），HBV（-）/AFB1（-）. Genomewide analysis was carried out using array-based comparative genomic hybridization（aCGH），and RT-PCR was used to detect RB1 mRNA expression. Results Deletion of 13q14.2 was found in 15 of 32（46.9%） samples overall，and deletion rates in each group were as follows: group A，80.0%（8/10）；group B，50.0%（5/10）；group C，33.3%（2/6）；and group D，0%（0/6）.Deletion rates differed significantly between groups A and C，A and D，and B and D（all P＜0.05）.RB1 mRNA expression was lower in the 15 cases with the 13q14.2 deletion than in the 17 cases possessing 13q14.2. Conclusions Genetic 13q14.2，are frequent molecular characteristics of HCC.Deletion of 13q14.2 may result from the synergistic effects of HBV and AFB₁，and it may contribute to RB1 gene inactivation in HCC.

Key words: Liver neoplasms, Hepatitis B Virus （HBV）, Aflatoxin B₁, Chromosome 13q14.2, RB1 gene