Anti-Phosphohistone H3-Positive Mitoses Are Linked to Pathological Response in Neoadjuvantly Treated Breast Cancer

Breast Care (Basel). 2017 Sep;12(4):244-250. doi: 10.1159/000463377. Epub 2017 Aug 2.

Abstract

Background: We evaluated breast cancer (BC) core biopsies taken before neoadjuvant chemotherapy (NACT) by immunohistochemistry using anti-phosphohistone H3 (PHH3) antibody to determine mitosis, and correlated the results to clinicopathological data and histopathological regression of resected tumor specimens after NACT.

Methods: 72 patients with either triple-negative (TN) or luminal type BC received NACT with epirubicin/cyclophosphamide (EC) and Taxotere®. Tumor regression was analyzed in resected specimens; pathological complete response (pCR) was achieved in 22.2%. Immunohistochemistry with PHH3 was performed on biopsy samples taken before treatment, and mitotic figures were evaluated in 10 high-power fields (HPF).

Results: PHH3-detected mitoses correlated significantly with tumor grading (p = 0.001). TNBC showed > 10 PHH3-positive mitoses/10 HPF significantly more frequently than luminal type BC (p = 0.003). Tumors with > 10 PHH3-positive mitoses/10 HPF achieved pCR significantly more often than those with ≤ 10 PHH3-positive mitoses/10 HPF (p = 0.031). Even luminal type BC with > 10 PHH3-positive mitoses/10 HPF was associated significantly with pCR compared to luminal type BC with ≤ 10 PHH3-positive mitoses/10 HPF (p = 0.016).

Conclusion: NACT with EC and Taxotere is suitable for strong proliferating TNBC and luminal BC (> 10 PHH3-positive mitoses/10 HPF). Immunohistochemical determination of mitoses using anti-PHH3 antibody is a simple and robust method for predicting therapy response to NACT in BC tissue.

Keywords: Breast cancer; Mitotic count; Neoadjuvant therapy; PHH3.