Current evidence on the relationship between HRAS1 polymorphism and breast cancer risk: a meta-analysis.

Rare alleles at the HRAS1 variable number of tandem repeats (VNTRs) locus have been implicated in breast cancer risk. Although many studies have showed that rare HRAS1 alleles may be associated with breast cancer risk, this relationship remains controversial. A meta-analysis was conducted to investigate the potential association between rare HRAS1 alleles and breast cancer risk. A database search found a total of 13 studies involving 1926 breast cancer cases and 2800 controls. Crude odds ratios (OR) and 95% confidence intervals (CI) were used to test the strength of association. When all the studies were combined into the meta-analysis, we found that breast cancer cases had a significantly higher frequency of rare alleles (OR = 2.03, 95% CI = 1.34, 3.10). In the subgroup analysis by race, we found that breast cancer cases had a significantly higher frequency of rare alleles (OR = 2.14, 95% CI = 1.37, 3.36) among Caucasians. In the subgroup analysis by study design, we found that breast cancer cases had a significantly higher frequency of rare alleles (OR = 2.47, 95% CI = 1.62, 3.79) among groups with hospital-based controls. In conclusion, this meta-analysis suggested that rare alleles at the HRAS1 VNTRs may contribute to breast cancer susceptibility. More population-based case-control studies were needed especially in Asians in the future.