NTRK1 and neoplasm: We propose that this characterises and establishes a new MCPyV positive MCC-subtype, unveils a novel MCPyV oncogenic mechanism and potential oncogenic function for MCPyV large T-antigen, identifies TrkAIII as novel potential therapeutic target and provides a rational for the use of Trk inhibitors, such as Larotrectinib, in the treatment of this MCPyV positive TrkAIII expressing tumour subtype.