Figure 2.

Representative pathological findings of precursors to high‐grade serous carcinoma. The p53 signature exhibited normal morphology with p53 overexpression, but without high proliferative activity, lacking MIB1 expression. Serous tubal intraepithelial carcinoma (STIC) shows cytological atypia and loss of polarity, p53 overexpression due to p53 mutation, and high proliferative activity with significant MIB1 expression. Serous tubal intraepithelial lesions (STILs) have intermediate findings of morphology and proliferative activity between the p53 signature and STIC, which are considered transitional lesions. All of these precursors are composed of PAX8‐positive secretory cells