Background: The differences between primary and metastatic tumor cells might be important for treatment selection and prognostication.
Materials & methods: Expression of ER, PR, HER2, CK5/6, EGFR, Ki-67, Ep-CAM, P-cadherin, CD24, CD44, ALDH was assessed immunohistochemically in primary tumor (T) and corresponding synchronous nodal metastases (LNM) in 156 invasive ductal breast cancer patients (T ≥1, N ≥1, M0).
Results: Independent negative prognostic factors for disease-free survival were pN3, ALDH immunopositivity in LNM, nonluminal A subtype in LNM, reduction of Ep-CAM expression in LNM, lack of changes or enhancement of CK5/6 and ALDH expression in LNM.
Discussion: Our results suggest that in some cases expression of markers in lymph node metastases might bring additional prognostic information to that obtained from primary tumor.
Keywords: breast carcinoma; changes in proteins expression; lymph node metastases; primary tumor.