Association between higher KI67 and higher proportion of effector T CD8 lymphocytes in HER2+ Breast Cancer patients

AYELÉN IVANA PESCE VIGLIETTI; MARIA BELEN BORDIGNON; ALEXIS OSTINELLI; FLORENCIA PERAZZO; MANGLIO MIGUEL RIZZO; FEDERICO COLÓ; GABRIEL CRIMI; IGNACIO MC LEAN; PABLO MANDÓ; ESTRELLA MARIEL LEVY

Ciudad Autónoma de Buenos Aires

Simposio; Bs As Breast Cancer Symposium; 2021

Association between higher KI67 and higher proportion of effector T CD8 lymphocytes in HER2+ Breast Cancer patients HER-2-amplified (HER2+) breast cancer (BC) is characterized by the high expression of genes related to human epidermal growth factor receptor 2 (ERBB2/HER2). HER2+ BC patients are treated with neoadjuvant (NA) chemotherapy including anti-Her2 antibodies, trastuzumab (TRZ), and pertuzumab (PER). We were interested in characterizing different subpopulations of peripheral blood T lymphocytes in patients with HER2+ BC undergoing NA therapy, considering that the adaptive immune profile in these patients could have an impact on the response to treatment so that their study could help to find predictive markers of the response. We analyzed by FACS T lymphocyte subpopulations such as exhaustion, activation, and memory on PBMC of 49 patients diagnosed before TRZ+PER therapy, and 23 healthy donors (HD). We also evaluated the association between immunological markers and clinical variables.The patients who presented a high tumor cell proliferation marker (Ki67> 20), associated with chemotherapy response, showed differences in memory populations with those patients with a Ki67 20, a lower proportion of CD8 + CM T cells (central memory) was observed (p = 0.0028; 0.047) and a greater proportion of effector CD8 + T cells (p = 0.0357; 0.023), supporting the role of immunotherapy in treating a subset of HER2+ BC. The role of T cell memory subsets predictors of response to neoadjuvant chemotherapy in HER2+ BC should be further evaluated.