NTRK1 and small cell carcinoma: When analysed by these parameters (Fig. 1H), 27/96 (28%) of squamous cell carcinomas expressed TrkA, compared to 1/55 (2%) of adenocarcinomas, 0/7 (0%) of small cell cancers and 1/121 normal tissues (<1%) (p < 0.0001), with 12/96 (13%) of squamous cell carcinomas showing very strong TrkA expression (h-score >100).