PIK3CA and neuroendocrine carcinoma: PIK3CA, WNK2, and KMT2B underwent mutations in both the dMMR-like subtype of NECC (50% – 75%) and in NECE (60% – 80%) specimens, while exhibiting infrequent mutational occurrences in publicly available data pertaining to neuroendocrine carcinomas of the lung or bladder (< 10%).