Density, Distribution, and Composition of Immune Infiltrates Correlate with Survival in Merkel Cell Carcinoma
Laurence Feldmeyer, Courtney W Hudgens, Genevieve Ray-Lyons, Priyadharsini Nagarajan, Phyu P Aung, Jonathan L Curry, Carlos A Torres-Cabala, Barbara Mino, Jaime Rodriguez-Canales, Alexandre Reuben, Pei-Ling Chen, Jennifer S Ko, Steven D Billings, Roland L Bassett, Ignacio I Wistuba, Zachary A Cooper, Victor G Prieto, Jennifer A Wargo, Michael T Tetzlaff, Laurence Feldmeyer, Courtney W Hudgens, Genevieve Ray-Lyons, Priyadharsini Nagarajan, Phyu P Aung, Jonathan L Curry, Carlos A Torres-Cabala, Barbara Mino, Jaime Rodriguez-Canales, Alexandre Reuben, Pei-Ling Chen, Jennifer S Ko, Steven D Billings, Roland L Bassett, Ignacio I Wistuba, Zachary A Cooper, Victor G Prieto, Jennifer A Wargo, Michael T Tetzlaff
Abstract
Purpose: Merkel cell carcinoma (MCC) is an aggressive cancer with frequent metastasis and death with few effective therapies. Because programmed death ligand-1 (PD-L1) is frequently expressed in MCC, immune checkpoint blockade has been leveraged as treatment for metastatic disease. There is therefore a critical need to understand the relationships between MCPyV status, immune profiles, and patient outcomes.
Experimental design: IHC for CD3, CD8, PD-1, PD-L1, and MCPyV T-antigen (to determine MCPyV status) was performed on 62 primary MCCs with annotated clinical outcomes. Automated image analysis quantified immune cell density (positive cells/mm2) at discrete geographic locations (tumor periphery, center, and hotspot). T-cell receptor sequencing (TCRseq) was performed in a subset of MCCs.
Results: No histopathologic variable associated with overall survival (OS) or disease-specific survival (DSS), whereas higher CD3+ (P = 0.004) and CD8+ (P = 0.037) T-cell density at the tumor periphery associated with improved OS. Higher CD8+ T-cell density at the tumor periphery associated with improved DSS (P = 0.049). Stratifying MCCs according to MCPyV status, higher CD3+ (P = 0.026) and CD8+ (P = 0.015) T-cell density at the tumor periphery associated with improved OS for MCPyV+ but not MCPyV- MCC. TCRseq revealed clonal overlap among MCPyV+ samples, suggesting an antigen-specific response against a unifying antigen.
Conclusions: These findings establish the tumor-associated immune infiltrate at the tumor periphery as a robust prognostic indicator in MCC and provide a mechanistic rationale to further examine whether the immune infiltrate at the tumor periphery is relevant as a biomarker for response in ongoing and future checkpoint inhibitor trials in MCC. Clin Cancer Res; 22(22); 5553-63. ©2016 AACR.
Conflict of interest statement
Disclosure of Potential Conflicts of Interest
No potential conflicts of interest were disclosed.
©2016 American Association for Cancer Research.
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Source: PubMed