FAT3 and rectum neuroendocrine neoplasm: DAXX, KMT2C, BCL2L1, LTK, MERTK, SPEN, PKN1, FAT3, and LRP2 mutations were found in only low‐grade rectal NETs, whereas APC, TP53, NF1, SOX9, and BRCA1 mutations were common in high‐grade rectal NECs/MiNENs.