Clinicopathological Correlates of γδ T Cell Infiltration in Triple-Negative Breast Cancer

Florence Boissière-Michot (1) , Ghita Chabab (1, 2, 3) , Caroline Mollevi (1, 4) , Séverine Guiu (1, 2, 3) , Evelyne Lopez-Crapez (2, 1, 3) , Jeanne Ramos (1) , Nathalie Bonnefoy (2, 1, 3) , Virginie Lafont (2, 1, 3) , William Jacot (1, 2, 3)

1 ICM - Institut régional de Cancérologie de Montpellier
2 IRCM - U1194 Inserm - UM - Institut de Recherche en Cancérologie de Montpellier
3 UM - Université de Montpellier
4 IDESP - Institut Desbrest de santé publique

The prognostic impact of the different tumor-infiltrating lymphocyte (TIL) subpopulations in solid cancers is still debated. Here, we investigated the clinicopathological correlates and prognostic impact of TILs, particularly of γδ T cells, in 162 patients with triple-negative breast cancer (TNBC). A high γδ T cell density (>6.625 γδ T cells/mm2) was associated with younger age (p = 0.008), higher tumor histological grade (p = 0.002), adjuvant chemotherapy (p = 0.010), BRCA1 promoter methylation (p = 0.010), TIL density (p < 0.001), and PD-L1 (p < 0.001) and PD-1 expression (p = 0.040). In multivariate analyses, γδ T cell infiltration (cutoff = 6.625 γδ T cells/mm2) was an independent prognostic factor (5-year relapse-free survival: 63.3% vs. 89.8%, p = 0.027; 5-year overall survival: 73.8% vs. 89.9%, p = 0.031, for low vs. high infiltration). This prognostic impact varied according to the tumor PIK3CA mutational status. High γδ T cell infiltration was associated with better survival in patients with PIK3CA wild-type tumors, but the difference was not significant in the subgroup with PIK3CA-mutated tumors. Altogether, these data suggest that high γδ T cell infiltrate is correlated with immune infiltration and might represent a candidate prognostic tool in patients with TNBC.

Domaines: Sciences du Vivant [q-bio]

Florence Boissière-Michot, Ghita Chabab, Caroline Mollevi, Séverine Guiu, Evelyne Lopez-Crapez, et al.. Clinicopathological Correlates of γδ T Cell Infiltration in Triple-Negative Breast Cancer. Cancers, 2021, 13 (4), pp.765. ⟨10.3390/cancers13040765⟩. ⟨hal-03687647⟩