TP53, STK11, and EGFR Mutations Predict Tumor Immune Profile and the Response to Anti-PD-1 in Lung Adenocarcinoma.

Purpose: By unlocking antitumor immunity, antibodies targeting programmed cell death 1 (PD-1) exhibit impressive clinical results in non-small cell lung cancer, underlining the strong interactions between tumor and immune cells. However, factors that can robustly predict long-lasting responses are still needed.Experimental Design: We performed in-depth immune profiling of lung adenocarcinoma using an integrative analysis based on immunohistochemistry, flow-cytometry, and transcriptomic data. Tumor mutational status was investigated using next-generation sequencing. The response to PD-1 blockers was analyzed from a prospective cohort according to tumor mutational profiles and PD-L1 expression, and a public clinical database was used to validate the results obtained.
Results: We showed that distinct combinations of STK11, EGFR, and TP53 mutations were major determinants of the tumor immune profile (TIP) and of the expression of PD-L1 by malignant cells. Indeed, the presence of TP53 mutations without co-occurring STK11 or EGFR alterations (TP53-mut/STK11-EGFR-WT), independently of KRAS mutations, identified the group of tumors with the highest CD8 T-cell density and PD-L1 expression. In this tumor subtype, pathways related to T-cell chemotaxis, immune cell cytotoxicity, and antigen processing were upregulated. Finally, a prolonged progression-free survival (PFS: HR = 0.32; 95% CI, 0.16-0.63, P < 0.001) was observed in anti-PD-1-treated patients harboring TP53-mut/STK11-EGFR-WT tumors. This clinical benefit was even more remarkable in patients with associated strong PD-L1 expression.Conclusions: Our study reveals that different combinations of TP53, EGFR, and STK11 mutations, together with PD-L1 expression by tumor cells, represent robust parameters to identify best responders to PD-1 blockade. Clin Cancer Res; 24(22); 5710-23. ©2018 AACR. ©2018 American Association for Cancer Research.