HNF1B and serous adenocarcinoma: Previously, HNF1B was found to be expressed specifically in ovarian CCC (as compared to other histotypes) [4]–[6], and recently HNF1B immunostaining was reported to be a sensitive (82.5% sensitivity) and specific (95.2% specificity) marker for the diagnosis of ovarian CCC (vs. high-grade serous carcinoma) [30].