Association of single nucleotide polymorphisms in the coding region of Bcl -2 with the occurrence and prognosis of colorectal cancer: A case-control study

OBJECTIVE: To investigate the relationship of single nucleotide polymorphisms in the coding region of Bcl-2 with the occurrence and prognosis of colorectal cancer (CRC).

METHODS: Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay was used detect Bcl-2 gene polymorphisms(rs1800477A/G and rs1801018A/G) in 185 patients with CRC (case group) and 177 healthy subjects (control group). The relationships of Bcl-2 gene polymorphisms with clinicopathological features and prognosis of CRC patients were analyzed.

RESULTS: The frequency of GG genotype and G allele of rs1800477A/G in the case group were significantly higher than those in the control group(both P < 0.05). The GG genotype of rs1800477A/G was associated with lymph node metastasis and Dukes' staging of CRC (both P < 0.05). Haplotype analysis demonstrated that the case group had decreased frequency of GA haplotype, but increased frequency of GG haplotype in comparisons to the control group (GA: P = 0.014; GG: P = 0.003). Kaplan-Meier survival analysis showed that the risk of death (within 5 years) in patients carrying GG genotype (rs1800477A/G) was 2.159 as much as that in patients carrying AA+ GA genotype. Multivariate analyses showed that Dukes' staging and GG genotype of rs1800477A/G are risk factors for poor prognosis in CRC (Dukes' staging: P = 0.001; GG genotype: P = 0.034).

CONCLUSION: Bcl-2 rs1800477A/G polymorphism may be related to the occurrence of CRC, and GG genotype could be a risk factor of poor prognosis in CRC.