Merkel cell carcinoma patients presenting without a primary lesion have elevated markers of immunity, higher tumor mutation burden and improved survival.

December 15, 2017


Clinical Cancer Research

Publication Date

December 15, 2017


Vandeven N, Lewis C, Makarov V, Riaz N, Paulson K, Hippe D, Bestick A, Doumani R, marx T, Takagishi S, Chan T, Choi J, Nghiem P

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PURPOSE: Patients presenting with nodal Merkel cell carcinoma without an identifiable (unknown) primary lesion (MCC-UP) are nearly twice as likely to survive compared to 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 was analyzed from 16 tumors.

RESULTS: As in prior studies, patients with nodal MCC-UP had strikingly improved MCC-specific survival as compared to 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). Additionally, 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)

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