Objective To discuss the difference in podocalyxin expression between ductal carcinoma in situ (DCIS) and invasive ductal carcinoma (IDC), and their relationships with clinicopathological parameters and prognosis of breast cancer.

Methods Immunohistochemical SP method was applied to detect the expression and location of podocalyxin in the breast tissues of 62 DCIS (33 cases of low/intermediate grade and 29 cases of high grade) and 129 IDC samples.

Results The expression of podocalyxin in DCIS and IDC were 35.48% (22/62) and 51.94% (67/129) (P < 0.05). It was preferentially expressed in high-grade DCIS, compared with low/intermediate-grade DCIS (P < 0.05). Podocalyxin expression in IDC was associated with tumor grade, pTNM stage and lymph node metastasis in IDC (P < 0.05). Kaplan-Meier univariate analysis revealed positive podocalyxin expression and other factors had significance for disease free survival. Cox model analysis revealed positive podocalyxin expression and lymph nodes metastasis were dangerous independent prognosis factor for IDC.

Conclusion Podocalyxin expression is significantly higher in IDC than that in DCIS. Podocalyxin could be an important index for the development and invasive of breast cancer. In IDC patients, podocalyxin positive expression is closely associated with poor prognosis.