RAS/MAPK activation is associated with reduced tumor-infiltrating lymphocytes in triple-negative breast cancer: therapeutic cooperation between MEK and PD-1/PD …
Clinical Cancer Research, 2016•AACR
Purpose: Tumor-infiltrating lymphocytes (TIL) in the residual disease (RD) of triple-negative
breast cancers (TNBC) after neoadjuvant chemotherapy (NAC) are associated with
improved survival, but insight into tumor cell-autonomous molecular pathways affecting
these features are lacking. Experimental Design: We analyzed TILs in the RD of clinically
and molecularly characterized TNBCs after NAC and explored therapeutic strategies
targeting combinations of MEK inhibitors with PD-1/PD-L1–targeted immunotherapy in …
breast cancers (TNBC) after neoadjuvant chemotherapy (NAC) are associated with
improved survival, but insight into tumor cell-autonomous molecular pathways affecting
these features are lacking. Experimental Design: We analyzed TILs in the RD of clinically
and molecularly characterized TNBCs after NAC and explored therapeutic strategies
targeting combinations of MEK inhibitors with PD-1/PD-L1–targeted immunotherapy in …
Abstract
Purpose: Tumor-infiltrating lymphocytes (TIL) in the residual disease (RD) of triple-negative breast cancers (TNBC) after neoadjuvant chemotherapy (NAC) are associated with improved survival, but insight into tumor cell-autonomous molecular pathways affecting these features are lacking.
Experimental Design: We analyzed TILs in the RD of clinically and molecularly characterized TNBCs after NAC and explored therapeutic strategies targeting combinations of MEK inhibitors with PD-1/PD-L1–targeted immunotherapy in mouse models of breast cancer.
Results: Presence of TILs in the RD was significantly associated with improved prognosis. Genetic or transcriptomic alterations in Ras–MAPK signaling were significantly correlated with lower TILs. MEK inhibition upregulated cell surface MHC expression and PD-L1 in TNBC cells both in vivo and in vitro. Moreover, combined MEK and PD-L1/PD-1 inhibition enhanced antitumor immune responses in mouse models of breast cancer.
Conclusions: These data suggest the possibility that Ras–MAPK pathway activation promotes immune-evasion in TNBC, and support clinical trials combining MEK- and PD-L1–targeted therapies. Furthermore, Ras/MAPK activation and MHC expression may be predictive biomarkers of response to immune checkpoint inhibitors. Clin Cancer Res; 22(6); 1499–509. ©2015 AACR.
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