TP53 and gastric cancer: The tumor suppressor p53, which is regulated by the TP53 gene, is critical in the prevention of cancer in normal cells.[13] Many human cancers, including breast and gastric cancer, are associated with TP53 mutations.[14,15]TP53 mutations are associated with a poor prognosis in breast cancer, especially in hormone receptor-negative and high-grade cancers.[16] In our study, TP53 mutations were associated with breast subtypes known to have a poor prognosis, such as TNBC or HER2-positive breast cancer.