Peripheral blood NK bright cells are augmented in breast cancer patients non-reaching pathologic complete response to antibody anti HER2+-based therapy

PESCE VIGLIETTI, AYELÉN; BORDIGNON, MARÍA BELÉN; OSTINELLI, ALEXIS; PERAZZO, FLORENCIA; RIZZO, MANGLIO MIGUEL; COLÓ, FEDERICO; MANDÓ, PABLO; LEVY, ESTRELLA MARIEL; CONSTANZO, VICTORIA; RIVERO, SERGIO G.

Congreso; BUENOS AIRES BREAST CANCER SYMPOSIUM, BA-BCS 2021; 2021

HER2+ breast cancer (BC) patients are treated withneoadjuvant therapy with trastuzumab and pertuzumab,both anti-HER2 antibodies. In this context, NK cells couldplay a fundamental role due to their ability to performADCC and secrete cytokines such as IFN-γ. We wereinterested in characterizing peripheral blood (PB) NKcells in BC patients compared to those from healthydonors (HD). Also, we wanted to determine if the peripheralimmune profile is associated with the responseto treatment with anti-HER2 antibodies. To do this, weanalyzed by FACS 10 NK cell receptors (CD57, NKp30,NKp44, CD16, NKG2A, CD25, NKG2C, CD16, PD-L1,and TIM-3) on PBMC of 49 patients diagnosed beforetrastuzumab+pertuzumab therapy and 23 HD. Patientspresented a higher percentage of NK dim compared to HD(95% vs 91%, p = 0.0022), and also showed a higher proportionof NK PD-L1+cells (4.13% vs 1.8%, p = 0.0069).Despite the low number of patients non-reaching pathologic complete response (5/37), it was found that theypresent a higher concentration of NK bright cells in PB(16 cells/µl vs 10 cells/µl, p = 0.0161). Moreover, thosepatients with lymph node involvement (36/47) presenteda higher percentage of NK cells than those without lymphnode involvement (11.74% vs 8.57%, p = 0.026). Thesepreliminary data exhibit several characteristics in HER2+patients that could be associated with therapy responsein the future. Currently, patient recruitment and functionaltests continue.