Association of pathological clinical characteristics, PD L 1 receptor expression (sp 142), with tumor lymphocytic infiltration cells (TILs) in patients (pts) with triple negative breast cancer (TNBC) in Tucumán, Argentina.

Abstract

e13049 Background: Breast cancer (BC) is the most prevalent tumor in women and the leading cause of cancer death in women. TNBC has the worst prognosis among BC subtypes and limited treatment options, mainly including chemotherapy. The efficacy of immunotherapy is clear for immunogenic tumors, such as melanoma, kidney cancer, non-lung cancer small cell, among others. BC seems to be less immunogenic. Basal-type TNBC present a prominent infiltration of inflammatory cells, suggesting that an immune pathway plays a role in tumorogenesis. The development of immunotherapy (IO)has reached an important turning point in the history of cancer treatment based on the use of the immune system itself to fight tumor cells. PD-L1 overexpression is the only predictive response biomarker for anti-PD-1 / PD-L1 therapy that is accepted in TNBM. Methods: Retrospectively, 68 cases of TNBC from the Pathological Anatomy Service of the Ntra. Sra. De las Mercedes Maternity Institute, of Tucumán, between 2010 and 2016 were analyzed. VENTANA anti PDL1 sp142 assay platform was used. Tumor-infiltrating immune cells (IC) are scored as the proportion of tumor area that is occupied by PD-L1 staining IC of any intensity. A specimen should be considered to have PD-L1 expression if the specimen exhibits ≥ 1% IC. In addition, carcinomas with a proportion greater than 50% of lymphocytic infiltration and its association with the expression of PD L1 were studied according to the recommendations of the International TILs Working group. Results: The median age of the patients was 56 years (21-80). The predominant histological type was non-specific type ductal carcinoma, reported in 45/68 cases (66%), following the medullar 9 / 68 (13%) lobular in 8/68 (11%), metaplastic 3/68 (4%) and other 4%. The tumor grade (G), half of the cases were G 3 with 34/68 (50%), G 2 with 42%. The largest proportion of pts, 42%, had no lymph node (LN) involvement, 33% had between 1 to 3 positive LN and 25% showed 4 or more LN. Stage II 39/68 patients (58%) in stage III 20/68 (30%), I (9%, 6) and IV (3%, 2). 16% (11/68) of the patients were PD-L1 positive. Tumors with lymphocytic infiltration between 0% and 10% expressed 24% (2/37), no expression was observed in tumors with TIls between 10 and 50% and in cases with lymphocytic infiltration greater than 50% expression of PD L was observed 1 in 9/18 cases (50%) (Fisher's exact test, p < 0.0001). Conclusions: It was demonstrated that there is an association between the stromal lymphocytic infiltrate (TILs) and the expression of PD-L1 in tumor cells, in this population of women from Tucumán, which would help to select patients as candidates for anti PD L1 therapies.