FOLR1 and serous adenocarcinoma: In a large cohort of 216 gynecologic malignancies, FRα positivity was observed in 45.4% of cases, with notable variation among histological subtypes: high-grade serous carcinomas (54.3%), carcinosarcomas (60%), and low-grade serous carcinomas (29.4%), while endometrioid, clear cell, mucinous, and granulosa cell tumors were negative [22].