PTEN and breast cancer: For subgroup analysis according to cancer type, PTEN IVS4 (−/−) genotype was observed to be associated with increased risk of digestive tract cancer (OR = 1.67, 95% CI = 1.28–2.18, P<0.001) but no significant association was found with breast cancer (OR = 1.27, 95% CI = 0.79–2.04, P = 0.318) or prostate cancer (OR = 1.20, 95% CI = 0.83–1.73, P = 0.342).