NTRK1 and skin basal cell carcinoma: In contrast to MCPyV positive MCCs, MCPyV negative MCC, BCCs, SCCs and normal skin samples exhibiting exclusive fully spliced TrkA mRNA expression, also exhibited variable TrkA immunoreactivity, strongest in normal skin epithelia and in 1 SCC but scant or non-existent in other BCC and SCC tissues, but were not immunoreactive for phosphorylated TrkA.