P-cadherin expression and basal-like subtype in breast cancers.

Breast cancer is considered as one of the multifactorial diseases. The aim of the current study is to investigate the association between P-cadherin and molecular subtypes of breast cancer, especially the basal-like subtype. Two hundred and thirteen breast-invasive ductal carcinomas were involved in this study. The expressions of P-cadherin were detected via immunohistochemistry. The 213 cases were divided into luminal A, luminal B, HER2 overexpression subtype, and normal breast-like and basal-like subtypes according to the standard of molecular breast cancer subtypes. In addition, the expressions of CK5/6 and CK14 were detected to distinguish between the normal breast-like and the basal-like subtypes. P-cadherin expression was found in 91 cases of 213 breast-invasive ductal carcinomas, with a positive rate of 42.7%. P-cadherin correlated negatively with estrogen receptor (ER) (p=0.001) and progesterone receptor (p=0.001), whereas it positively correlated with histologic grade (p=0.003), NPI (p=0.005), p53 (p=0.038), and Ki67 (p=0.022). P-cadherin expression showed a strong correlation with recurrence and distant metastasis (p=0.009), and invasion of the vascular and soft tissues (p=0.004). Moreover, P-cadherin expression existed in the basal-like and non-basal-like subtypes. During prognosis, P-cadherin expression was associated with decreased disease-free survival in patients (p=0.009) and overall survival (OS) (p=0.005). In addition, multivariate analysis showed that tumor grade (p=0.021), ER (p=0.015), clinical stage (p=0.001), and P-cadherin (p=0.033) were significant predictors of OS. The current data suggest that P-cadherin may be used to distinguish the basal-like subtype and to predict the outcome in view of the relationship with DFS and OS. Furthermore, P-cadherin expression may be useful in making treatment decisions.