Genetic Polymorphisms in DNA Repair Genes XRCC4 and XRCC5 and Aflatoxin B1-related Hepatocellular Carcinoma
ABSTRACT Genetic polymorphisms in DNA repair genes may influence individual variation in DNA repair capacity and may play an important role in carcinogenesis. We investigated the role of genetic polymorphisms at XRCC4 codon 247 (rs3734091, XRCC4P) and XRCC5 codon 180 (rs80309960, XRCC5P) in liver cancer (hepatocellular carcinoma) caused by aflatoxin B1 (AFB1).
A hospital-based case-control study, including 1499 liver cancer cases and 2045 controls without any liver disease, was conducted in a high aflatoxin exposure area in the Guangxi region of China to assess the relationship between these two polymorphisms and aflatoxin-related liver cancer risk and prognosis. Genotypes, mRNA levels, and the hot-spot mutation of TP53 gene (TP53M) related to AFB1 exposure was tested using TaqMan-PCR technique. XRCC4 protein level was analyzed by immunohistochemistry.
For XRCC4P and XRCC5P, only XRCC4P modified liver cancer risk. Compared with the homozygote of XRCC4 codon 247 Ala alleles (XRCC4-AA), the genotypes of XRCC4 codon 247 Ser alleles (namely XRCC4-AS or -SS) increased liver cancer risk (odds ratio [OR] = 1.35 and 2.02, respectively). Significant interactive effects between risk genotypes (OR > 1) and aflatoxin exposure status were also observed in the joint effects analysis. Moreover, this polymorphism was associated not only with lower XRCC4 expression levels but also with higher AFB1-DNA adduct levels and increasing TP53M and portal vein tumor risk. Additionally, XRCC4P modified the recurrence-free survival and overall survival of cases, especially under conditions of high aflatoxin exposure.
XRCC4P may be a genetic modifier for the risk and outcome of hepatocellular carcinoma induced by AFB1 exposure.
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ABSTRACT: The Rho GTPase-activating protein 35 (ARHGAP35), an important Rho family GTPase-activating protein, may be associated with tumorigenesis of some tumors. Here, we investigated the relationship between an important polymorphic variant at 3'-UTR of this gene (rs1052667) and osteosarcoma risk and prognosis. This hospital-based case-control study, including 247 osteosarcoma patients and 428 age-, sex-, and race-matched healthy controls, was conducted in Guangxi population. Genotypes were tested using TaqMan PCR technique. We found a significant difference in the frequency of rs1052667 genotypes between cases and controls. Compared with the homozygote of rs1052667 C alleles (rs1052667-CC), the genotypes with rs1052667 T alleles (namely, rs1052667-CT or -TT) increased osteosarcoma risk (odds ratios: 2.41 and 7.35, resp.). Moreover, rs1052667 polymorphism was correlated with such pathological features of osteosarcoma as tumor size, tumor grade, and tumor metastasis. Additionally, this polymorphism also modified the overall survival and recurrence-free survival of osteosarcoma cases. Like tumor grade, ARHGAP35 rs1052667 polymorphism was an independent prognostic factor influencing the survival of osteosarcoma. These results suggest that ARHGAP35 rs1052667 polymorphism may be associated with osteosarcoma risk and prognosis.BioMed Research International 07/2014; 2014:396947. DOI:10.1155/2014/396947 · 2.71 Impact Factor
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ABSTRACT: Hepatocellular carcinoma (HCC) is the sixth common cancer and the third common cause of cancer mortality worldwide. However, the exact molecular mechanism of HCC remains uncertain. Caveolin-1 (CAV1) is the main protein in the caveolin family and plays an important role in tumorigenesis signaling. However, the contribution of CAV1 genetic variants to HCC is still unknown. The purpose of this study was to evaluate the association between the tagSNPs of the CAV1 gene and HCC risk. In this case-control study, we enrolled 1,000 HCC patients and 1,000 cancer-free controls, which were frequency-matched by age, gender, and HBV infection status. We found that CAV1 rs729949 was statistically associated with increased risk of HCC (odds ratio (OR) = 1.28; 95 % confidence interval (CI), 1.11-1.48; P = 8.53 × 10(-4)), even after Bonferroni correction (P = 5.97 × 10(-3)); the expression levels of CAV1 in cancer tissues were significantly lower than those in adjacent normal tissues (P = 0.012). We also detected a significant association for CAV1 rs3807989 under the log-additive model (OR = 0.85; 95 % CI, 0.74-0.98; P = 0.026). Significant associations were also detected for CAV1 rs6466583 (GG vs AA: OR = 2.53; 95 % CI, 1.24-5.17; P = 0.011) and CAV1 rs3807986 (AG vs AA: OR = 3.16; 95 % CI, 1.68-5.91; P = 3.36 × 10(-4)) among genotype comparisons. These findings indicated that genetic variants n CAV1 might contribute to HCC susceptibility.Tumor Biology 08/2014; DOI:10.1007/s13277-014-2428-5 · 2.84 Impact Factor
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ABSTRACT: Aflatoxin B1 (AFB1) is an important environmental carcinogen and can induce DNA damage and involve in the carcinogenesis of hepatocellular carcinoma (HCC). The deficiency of DNA repair capacity related to the polymorphisms of DNA repair genes might play a central role in the process of HCC tumorigenesis. However, the interaction of DNA repair gene polymorphisms and AFB1 in the risk of hepatocellular carcinoma has not been elucidated. In this study, we investigated whether six polymorphisms (including rs25487, rs861539, rs7003908, rs28383151, rs13181, and rs2228001) in DNA repair genes (XPC, XRCC4, XRCC1, XRCC4, XPD, XRCC7, and XRCC3) interacted with AFB1, and the gene-environmental interactive role in the risk of HCC using hospital-based case-control study (including 1486 HCC cases and 1996 controls). Genotypes of DNA repair genes were tested using TaqMan-PCR technique. Higher AFB1 exposure was observed among HCC patients versus the control group [odds ratio (OR) = 2.08 for medium AFB1 exposure level and OR = 6.52 for high AFB1 exposure level]. Increasing risk of HCC was also observed in these with the mutants of DNA repair genes (risk values were from 1.57 to 5.86). Furthermore, these risk roles would be more noticeable under the conditions of two variables, and positive interactive effects were proved in the followed multiplicative interaction analysis. These results suggested that DNA repair risk genotypes might interact with AFB1 in the risk of HCC.