RB1 and in situ carcinoma: Subsequent driver mutations involve amplification of the Rb pathway gene CCNE1 [3] frequently found in serous tubal intraepithelial carcinoma (STIC), the morphologically fully transformed in situ carcinoma typically found in BRCA1/2 carriers [4] before the development of HGSC in the ovary or peritoneum [5, 6].