PTP1B is involved in the oncogenesis of breast cancer. In addition, neoadjuvant therapy has been widely used in breast cancer; thus, a measurement to assess survival improvement could be pathological complete response (pCR). Our objective was to associate PTP1B overexpression with outcomes of breast cancer patients who underwent neoadjuvant chemotherapy. Forty-six specimens were included. Diagnostic biopsies were immunostained using anti-PTP1B antibody. Expression was categorized as negative (<5%) and overexpression (≥5%). Patients' responses were graded according to the Miller-Payne system. Sixty-three percent of patients overexpressed PTP1B. There was no significant association between PTP1B overexpression and pCR (P = 0.2). However, when associated with intrinsic subtypes, overexpression was higher in human epidermal growth factor receptor 2-positive-enriched specimens (P = 0.02). Ten-year progression-free survival showed no differences. Our preliminary results do not show an association between PTP1B over-expression and pCR; however, given the limited sample and heterogeneous treatment in our cohort, this hypothesis cannot be excluded.
Keywords: PTP1B protein; breast cancer; neoadjuvant therapy.