Differential prognostic impact of CD8+ T cells based on human leucocyte antigen I and PD-L1 expression in microsatellite-unstable gastric cancer
Menée à partir d'échantillons tissulaires du centre de tumeurs et de marges invasives provenant de 293 patients atteints d'un cancer de l'estomac avec haute instabilité des microsatellites, cette étude évalue, en fonction de l'expression des molécules de classe I du système HLA, l'association entre la densité intratumorale des lymphocytes CD8+ et le pronostic
Background : The aim of the study was to determine the human leucocyte antigen class-I (HLA-I), programmed death-ligand 1 (PD-L1) expression and tumour-infiltrating lymphocytes (TILs) of microsatellite instability-high gastric cancer. Methods : The HLA-I expression type was determined by immunohistochemistry of HLA-A, HLA-B, HLA-C and
β2-microglobulin in the centre of the tumour (CT) and in the invasive margin (IM) of samples from 293 patients (total loss vs. preserved type). PD-L1 expression and TIL density was examined immunohistochemically. HLA-I genotyping was also performed. Results
:
The expression loss of the HLA-I molecules was significantly associated with low TIL density. According to survival analyses, the HLA-I expression type and PD-L1 positivity were not independent prognostic factors. The TIL density had no prognostic implication when survival analysis was performed for the whole patient group; however, high CD8+ TIL infiltration was significantly associated with good prognosis in only HLA-I-preserved-type/PD-L1-positive group (p
= 0.034). The homozygosity of the HLA-I allele was more frequently observed in the total loss type group. Conclusions : We confirmed differential prognostic implication of CD8+ TILs according to the HLA-I and PD-L1 expression. Determination of the HLA-I expression could be helpful to select patients who would benefit from anti-PD-1/PD-L1 therapy.
British Journal of Cancer , résumé, 2020