Yokohama Breast and Gastrointestinal Clinic, Yokohama, Kanagawa, Japan
Review Article
Resistance to Neoadjuvant Chemotherapy in Triple-Negative Breast Cancer: Importance of Ki-67 Labeling Index and the Recognition of Apocrine-type Lesions
Author(s): Koichi Kubouchi and Yutaka Tsutsumi*
Triple-Negative Breast Cancer (TNBC) encompasses heterogeneous subtypes. Apocrine-type TNBC, defined as TNBC immunoreactive for both androgen receptor and forkhead-box protein A1, should be distinguished from basal-like TNBC. In apocrine-type TNBC, neoadjuvant chemotherapy (NAC) tends to be ineffective, but with a favorable prognosis despite chemoresistance. We analyzed 51 cases of TNBC in stages I and II. Thirty-four TNBCs treated with NAC were divided into “good responders” (n=22) showing therapeutic effect G2b or G3 in surgical specimens and “poor responders” (n=12) with therapeutic effect G0, G1a, G1b and G2a. NAC was spared in 17 cases (categorized as the non-NAC group). TNBC other than apocrine-type (n=16) and special types (myoepithelial, medullary, adenoid cystic and spindle cell carcinomas, n=6) was categorized as basal-like subtype (n=29). The prognos.. Read More»