In the subgroup meta-analysis by age stratification, HER2 codon 655 polymorphism was significantly associated with breast cancer in young women under all genetic models, including the additive model (OR 1.53, 95% CI 1.07-2.17; I2=67.3%; n=6), dominant model (OR 1.27, 95% CI 1.02-1.58; I2=40.5%; n=9), and recessive model (OR 3.09, 95% CI 1.06-8.99; I2=52.8%; n=4). This evidence concerns the gene ERBB2 and breast carcinoma.