INSM1 and squamous cell carcinoma: A proof of concept study by Doxtader et al. reported findings from INSM1 staining in 74 specimens and found that INSM1 was positive in 92% (48/52) of primary lung NE neoplasms, including 93% (38/41) of SCLCs, the only case of LCNEC and 90% (9/10) of carcinoid tumors, and negative in all 22 of non-neuroendocrine primary lung tumors including 11 adenocarcinomas, 9 squamous cell carcinomas, 1 mesothelioma, and 1 poorly differentiated non-small cell lung carcinoma, not otherwise specified [28].