NTRK1 and Merkel cell skin cancer: Furthermore, MCPyV positive MCCs exhibited a significantly lower TrkA:18S rRNA RT-PCR ratio of 0.063 ± 0.07 (mean ± SD) compared to 0.39 ± 0.37 in MCPyV negative MCC, BCCs, SCCs and normal skin (p = 0.0015, df = 24) and a significantly higher TrkAIII:18S rRNA ratio of 0.34 ± 0.25 (mean ± SD) compared to 0.014 ± 0.024 in MCPyV negative MCC, BCCs, SCCs and normal skin (p < 0.0009, df = 14) (Fig. 1b, Table 2).