TP53 and ovarian serous adenocarcinoma: The most frequent subgroup, accounting for 70% of all EOCs, is high-grade serous ovarian cancer (HGSOC), which is considered to originate from serous tubal intra-epithelial carcinoma (STIC) and is characterized by mutation in TP53 gene in 95% of cases.TP53 is the most frequently mutated gene in cancer, with mutations identified in at least 50% of human malignancy.