TY - JOUR T1 - 190 Perioperative dynamic evaluation of folate receptor alpha expression in ovarian carcinoma JF - International Journal of Gynecologic Cancer JO - Int J Gynecol Cancer SP - A207 LP - A208 DO - 10.1136/ijgc-2021-ESGO.355 VL - 31 IS - Suppl 3 AU - MP Kubelac AU - C Vlad AU - B Pop AU - B Fetica AU - E Fischer-Fodor AU - O Soritau AU - O Balacescu AU - F Ignat AU - G Lazar AU - C Lisencu AU - A Rancea AU - A Irimie AU - P Achimas-Cadariu Y1 - 2021/10/01 UR - http://ijgc.bmj.com/content/31/Suppl_3/A207.2.abstract N2 - Introduction/Background*The human folate receptor α (FOLR1) is overexpressed in ovarian cancer and has been correlated with the transformed phenotype in ovarian cancer, platinum sensitivity, and tumor growth. The highly restricted distribution of FOLR1 in normal tissues may increase it’s diagnostic and therapeutic potential through targeted agents currently under development. We characterized the FOLR1 serum expression in benign and malignant ovarian pathology pre- and postoperatively.Methodology Patients with suspected ovarian cancer treated at our Institution between 2018-2021 were prospectively enrolled. Pre- and/or postoperative (1-8 days after) blood samples were taken. Quantitative measurement of FOLR1 serum concentration was carried out by ELISA.Result(s)*Median age of participating patients was 53 (range 40-78). On definitive pathology 13 (22%) patients had benign adnexal masses and 46 (78%) had serous ovarian cancer. Thirty-seven (63%) patients had FIGO stage III-IV and 15 (25%) received neoadjuvant chemotherapy (NACT). Preoperative FOLR1 was significantly higher in the malignant group versus cases with benign pathology (mean 2190 ng/mL vs 499 ng/mL, p=0.001). NACT patients had a significantly lower preoperative FOLR1 than chemotherapy naïve patients (mean 1001 ng/mL vs 2765 ng/mL, p=0.012). Additionally, the preoperative FOLR1 in chemotherapy naïve patients was significantly higher in advanced-stage disease FIGO III-IV versus early-stage disease FIGO I-II (3317 ng/mL vs 1179 ng/mL, p=0.023). In paired pre- and postoperative samples no significant FOLR1 difference was noted (n=19, p=0.64), however for paired samples taken up to 3 days postoperatively a significant increase was seen in the postoperative value (1547 ng/mL vs 1768 ng/mL, p=0.047, n=7). Interestingly, 1/7 (14%) cases demonstrated a decrease in postoperative FOLR1 in the first 3 days while 8/12 (66.6%) cases had a decrease in postoperative FOLR1 4-8 days after (p=0.027).Conclusion*Elevated serum FOLR1 values correlated with malignancy and advanced stage while NACT significantly reduced FOLR1 values, in correlation with disease burden. We describe here a significant postoperative surge of FOLR1 that decreases >3 days after surgery that requires subsequent investigation. The full diagnostic and therapeutic potential of FOLR1 is yet to be explored and further analysis in corresponding tissue samples is ongoing.This work was supported by CNCS-UEFISCDI project PN-III-P4-PCCF-2016-0142. ER -