CD117 expression was observed in 30 of 33 thymic carcinomas (23 of 23 squamous cell carcinomas [SQCC], 5 of 6 large-cell neuroendocrine carcinomas [LCNEC], 1 of 1 basaloid carcinoma [BC], and 1 of 1 mucoepidermoid carcinoma [MEC]). The gene discussed is KIT; the disease is thymic carcinoma.