The characteristics of breast cancer subtypes: implications for treatment guidelines and individualized treatment strategies in China.

Abstract This study aimed at investigating the characteristics of invasive breast cancer among molecular subtypes. Patients with invasive breast cancer, with complete information on the expressions of estrogen receptor, progesterone receptor, and human epidermal growth factor receptor-2 (HER2), were recruited. χ tests and an unconditional logistic regression model were used for statistical analysis. The percentages of luminal A, luminal B, HER2/neu, and triple-negative subtypes were 54.2% (1639/3021), 14.0% (422/3021), 8.9% (269/3021), and 22.9% (691/3021), respectively. Differences among molecular subtypes (P<0.05) in tumor size, stage, pathologic type, and lymph node status were observed. The HER2/neu, luminal B, and triple-negative subtypes were more aggressive compared with the luminal A subtype in tumor stage, lymph node status, or pathologic type (P<0.05), when the findings were adjusted for age. Molecular subtypes were distributed differently between both age groups and regional groups on the basis of the socioeconomic status (P<0.05). In conclusion, luminal A and triple-negative subtypes were the 2 main subtypes of invasive breast cancer in China. The variations of molecular subtypes in pathology, age, and regional distribution may give some suggestions for updating treatment guidelines and individualized treatment strategies in China.