TP53 and serous adenocarcinoma: For example, p53 gene immunohistochemical expression patterns can be used to differentiate high grade serous carcinoma (HGSC) in which the expression is diffuse and intense (mutant) from low-grade serous carcinoma (LGSC) that usually show (wild-type) p53 staining, with a weak focal, and heterogeneous [12].