RESUMO
Immune checkpoint receptors (ICRs) were recently found to modulate the anti-tumoral immune response. This study aimed to determine the clinical and pathological associations of ICRs expression on tumor-infiltrating lymphocytes (TILs) in patients with locally advanced breast cancer (LABC) treated with neoadjuvant chemotherapy (NAC). Expressions of ICRs including PD-1, LAG-3, TIM-3, TIGIT, and CTLA-4 on CD8+ T lymphocytes and Natural Killer (NK) cells on TILs were analyzed by flow cytometry. Patients <50 years were more likely to express CTLA-4 on CD8+ T lymphocytes compared to those ≥50 years (p=0.004). In addition, patients with ypT3-4 tumors were more likely to have increased LAG-3 expression on CD16-CD56bright NK cells (p=0.042) and PD-1 (p=0.014) and CTLA-4 (p=0.018) expressions on CD8+ T cells in regard to those with ypT1-T2, respectively. Contrarily, PD-1 expression on CD16-CD56bright NK cells was found to be decreased in patients with ypN+ compared to those with ypN- (p=0.022). Furthermore, patients with HER2+ tumors were more likely to have increased TIM-3 expression on CD8+ T cells (p=0.043), whereas patients with a better response to NAC were more likely to express TIGIT on CD8+ T (p=0.014) and CD16-CD56bright NK cells (p=0.003), respectively. The new generation ICRs, TIM-3, LAG-3, and TIGIT are highly expressed in LABC following NAC in patients with poor prognostic factors. Therefore, new evolving therapies using inhibitory mAbs directed to TIM-3, LAG-3, and TIGIT could be also be considered in locally advanced breast cancers expressing these ICRs.