American Association for Cancer Research
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Table S1 from Merkel Cell Carcinoma Patients Presenting Without a Primary Lesion Have Elevated Markers of Immunity, Higher Tumor Mutation Burden, and Improved Survival

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journal contribution
posted on 2023-03-31, 19:52 authored by Natalie Vandeven, Christopher W. Lewis, Vladimir Makarov, Nadeem Riaz, Kelly G. Paulson, Daniel Hippe, Amy Bestick, Ryan Doumani, Tessa Marx, Seesha Takagishi, Timothy A. Chan, Jaehyuk Choi, Paul Nghiem

Patients with unknown primary lesions and without immunosuppression have improved survival among patients with stage IIIB and stage IV MCC



Ruth K. Freinkel Research

Foglia family



Purpose: Patients presenting with nodal Merkel cell carcinoma without an identifiable (unknown) primary lesion (MCC-UP) are nearly twice as likely to survive compared with similarly staged patients with known primary lesions (MCC-KP). The basis of this previously reported finding is unclear.Experimental Design: Survival analyses and markers of immunity were evaluated in 123 patients with advanced MCC. Whole-exome sequence data were analyzed from 16 tumors.Results: As in prior studies, patients with nodal MCC-UP had strikingly improved MCC-specific survival as compared with MCC-KP patients (HR, 0.297; P < 0.001). Surprisingly, patients presenting with distant metastatic MCC-UP also had significantly improved survival (HR, 0.296; P = 0.038). None of the 72 patients with MCC-UP were immunosuppressed as compared to 12 of the 51 (24%) patients with MCC-KP (P < 0.001). Merkel polyomavirus oncoprotein antibody median titer was higher in MCC-UP patients (26,229) than MCC-KP patients (3,492; P < 0.001). In addition, the median number of nonsynonymous exome mutations in MCC-UP tumors (688 mutations) was markedly higher than MCC-KP tumors (10 mutations, P = 0.016).Conclusions: This is the first study to our knowledge to explore potential underlying immune-mediated mechanisms of MCC-UP presentation. In this cohort, MCC-UP patients were never immune suppressed, had higher oncoprotein antibody titers, and higher tumor mutational burdens. In addition, we show that nodal tumors identified in MCC-UP patients did indeed arise from primary skin lesions as they contained abundant UV-signature mutations. These findings suggest that stronger underlying immunity against MCC contributes to primary lesion elimination and improved survival. Clin Cancer Res; 24(4); 963–71. ©2017 AACR.