IMMUNE CHARACTERIZATION OF HER-2 POSITIVE (HER-2+), HORMONE RECEPTOR POSITIVE (HR+) AND NEGATIVE (HR-) BREAST CANCER (BC) PATIENTS.

PINKASZ, MARINA; ROMANO, SOFIA; JULIÁ, ESTEFANÍA; OSTINELLI, ALEXIS; CUETO, GERARDO; SANCHEZ, MARIA BELÉN; PERAZZO FLORENCIA; RIZZO, MANGLIO; COSTANZO VICTORIA; MORDOH, JOSÉ; MANDÓ PABLO; LEVY, ESTRELLA

San Miguel de Tucumán

Congreso; LXVII Reunión Científica Anual de la Sociedad Argentina de Inmunología; 2019

Sociedad Argentina de Inmunología

Recent data from neoadjuvant trials support the hypothesis that, in HER2+ BC patients, the HR status influences the response to antibody-based targeted therapy. There is an increasing awareness of the relationship between the immune system and BC evolution. Moreover, it is possible that immune suppression accounts for the worst outcome in HER2+ HR+ patients, and that suppressive immune cells and molecules represent new prognostic markers for this BC subtype.We characterized the peripheral immune cell profile in HER2+, HR+ and HR- BC patients. Peripheral blood mononuclear cell samples were collected from 25 patients diagnosed with HER2+ BC before trastuzumab and pertuzumab neoadjuvant therapy and from 10 healthy donors (HD). Immunophenotypic profile characterizing different T lymphocyte markers (activated, exhausted and memory) were assessed by flow cytometry.Results showed that HR+ patients had a significant lower level of central memory CD8+ T cells than HR- patients and HD (mean HR+ 6,2% vs HR- 10,4%, p=0,04; and HD 9,3% p= 0,02; non-parametric t-test). In accordance, HR+ patients had a lower percentage of CD28+ CD8+ T cells (mean 63,3% vs 79,6%, p= 0,004; parametric t-test), and higher levels of effector CD8+ T lymphocytes (mean 38,6% vs 22,5%, p= 0,007; parametric t-test) than HD, whereas there were no significant differences between HR- patients and HD, for these markers.Preliminary data identified systemic immune markers differentially expressed in HR+ compared to HR- patients and HD. Patient recruitment is still ongoing, and new data could contribute to understand the worst outcome in this group of patients.