TP53 and neuroendocrine carcinoma: Impaired or abnormal tumour suppressor protein p53 expression has been found to be an important marker of aggressive disease in several cancer forms, including GEP-NEC, where abnormal immunohistochemistry (IHC) expression of the p53 protein indicating mutations, or inactivating mutations in the TP53 gene are the most common molecular alterations observed, regardless of primary site [2].