Tumor-associated macrophages (TAMs) and tumor-infiltrating lymphocytes (TILs) in pretherapeutic breast cancer core biopsies: Anti-tumoral effect of immune cells associated with neoadjuvant chemotherapy

Abstract

Purpose: Infiltration of immune cells may be associated with response to chemotherapy. To assess the relationship between tumor-associated macrophages (TAMs) or tumor-infiltrating lymphocytes (TILs) and short-term response to neoadjuvant chemotherapy (NAC), we analyzed TAM/TILs in pre-NAC breast cancer core biopsy (PNB) and their therapeutic contribution to the effectiveness of NAC based on the curative surgical specimen after NAC. Methods: In 154 neoadjuvant cohort cases of primary invasive breast cancer, we immunohistochemically measured subtypes (M1 and M2) of TAMs and histologically valued stromal TILs in PNB samples and assessed their correlation with tumor response by pathologic complete response (pCR) and clinicopathological charateristics. Results: Although higher CD163-positive M2 score was significantly associated with aggressive clinicopathological features including older age (>= 45) (P=0.041), higher tumor grade (P=0.001), higher Ki-67 proliferative index (>= 20%) (P<0.001), ER negativity (P<0.001), PR negativity (P<0.001) and triple negative type (P=0.023), it was associated with better NAC outcome such as smaller post-NAC tumor size (<1.5 cm) (P=0.007), low post-NAC pathologic T stages (P=0.021), absence of post-NAC nodal metastasis (P=0.048) and more frequent pCR (P=0.018). High TIL score was also related to smaller post-NAC tumor size (<1.5 cm) (P=0.021), low post-NAC pathologic T stages (P=0.003) and high pCR rate (P=0.037). Conclusion: A greater number of TAMs and TILs in the pretherapeutic core biopsy specimen were associated with better outcome after NAC for breast cancer and have antitumoral effect associated with NAC.