TP53 and neoplasm: This study showed that somatic mutations were infrequent in these tumours (34.6%) and confirmed previously described mutations in genes considered “drivers” in Si-NETs, such as CDKN1B (9.6%), APC (7.7%), and BRAF (3.8%) [53,54,58], but also in other genes not previously described in these neoplasms, such as CDKN2C (7.7%), KRAS (3.8%), PIK3CA (3.8%), and TP53 (3.8%).