Biomarkers Predicting Pathologic Complete Response to Neoadjuvant Chemotherapy in Breast Cancer

Recent studies have shown strong correlation of pathologic complete response (pCR) to neoadjuvant chemotherapy with survival and prognosis in breast cancers. Clinical data from 237 breast cancer patients who received neoadjuvant chemotherapy between 2012 and 2014 were reviewed. Correlations were sought between pCR and estrogen receptor (ER), progesterone receptor (PR), and HER2 status; Nottingham and nuclear grades; tumor tubule formation; mitotic score; Ki67 index; and tumoral and stromal lymphocytic infiltration (TLI and SLI, respectively). Of the 237 cases, 104 (43.9%) achieved pCR. The HER2+ and triple negative breast cancer (TNBC) subtypes had higher pCR rates compared with the luminal subtype (ER+ or PR+ and HER2-). ER and PR negativity, HER2 positivity, Nottingham grade 3, increased TLI and SLI, high mitotic count and Ki67 score correlated significantly with pCR in the overall cohort. TLI and SLI correlated significantly with pCR in the HER2+ and TNBC subtypes in multivariate analysis, whereas no biomarkers correlated with pCR in the luminal subtype. In addition to the pathologic parameters and biomarkers already routinely assessed, evaluation of TLI and SLI may help to better select patients with HER2+ and TNBC for neoadjuvant chemotherapy.