Onkologie. 2026:20(2):78-80 | DOI: 10.36290/xon.2026.014
Folate receptor alpha (FRα) testing: a pathologist's perspective
- Ústav patologie, Fakultní nemocnice Brno
The development of targeted and personalised oncologic therapies has significantly increased the importance of predictive biomarkers in clinical practice. Pathological diagnostics, therefore, no longer serve solely to establish a histological diagnosis but increasingly provide information essential for selecting systemic treatment. One of the predictive biomarkers in high-grade serous ovarian carcinoma is folate receptor alpha (FRα), whose expression is assessed by immunohistochemistry and is used to identify patients who may benefit from treatment with the antibody-drug conjugate mirvetuximab soravtansine. The aim of this article is to summarise the practical aspects of FRα expression testing in routine pathological practice and to highlight the main pitfalls in its interpretation.
Keywords: ovarian cancer, folate receptor alpha, immunohistochemistry, mirvetuximab soravtansine, predictive biomarker.
Accepted: April 20, 2026; Published: April 28, 2026 Show citation
References
- Cabasag CJ, Arnold M, Butler J, et al. The influence of birth cohort and calendar period on global trends in ovarian cancer incidence. International Journal of Cancer. 2020;146(3):749-758.
Go to original source... - Wallace-Povirk A, Hou Z, Nayeen MJ, et al. Folate Transport and One-Carbon Metabolism in Targeted Therapies of Epithelial Ovarian Cancer. Cancers (Basel). 2021;14(1):191. doi: 10.3390/cancers14010191. PMID: 35008360; PMCID: PMC8750473. Go to original source...
Go to PubMed... - Birrer MJ, Betella I, Martin LP, et al. Is Targeting the Folate Receptor in Ovarian Cancer Coming of Age? Oncologist. 2019;24(4):425-429. doi: 10.1634/theoncologist.2018-0459. Epub 2019 Jan 11. PMID: 30635448; PMCID: PMC6459241. Go to original source... Go to PubMed...
- Scaranti M, Cojocaru E, Banerjee S, et al. Exploiting the folate receptor α in oncology. Nat Rev Clin Oncol. 2020;17(6):349-359. doi: 10.1038/s41571-020-0339-5. Epub 2020 Mar 9. PMID: 32152484. Go to original source...
- Elnakat H, Ratnam M. Distribution, functionality and gene regulation of folate receptor isoforms: implications in targeted therapy. Adv Drug Deliv Rev. 2004;56(8):1067-1084. doi: 10.1016/j.addr.2004.01.001. PMID: 15094207. Go to original source... Go to PubMed...
- Chelariu-Raicu A, Mahner S, Moore KN, et al. Integrating antibody drug conjugates in the management of gynecologic cancers. Int J Gynecol Cancer. 2023;33(3):420-429. doi: 10.1136/ijgc-2022-003701. PMID: 36878560. Go to original source... Go to PubMed...
- Chen X, Jiang L, Ruan L, et al. Performance of the VENTANA FOLR1 Assay for folate receptor alpha: Real-world evidence from 313 Chinese participants. Pathol Res Pract. 2026;279:156359. doi: 10.1016/j.prp.2026.156359. Epub 2026 Jan 6. Erratum in: Pathol Res Pract. 2026 Feb 26:156422. doi: 10.1016/j.prp.2026.156422. PMID: 41512768. Go to original source... Go to PubMed...
- Previs RA, Strickland KC, Wallen Z, et al. Analysis of real world FRα testing in ovarian, fallopian tube, and primary peritoneal cancers. Gynecol Oncol. 2025;192:102-110. doi: 10.1016/j.ygyno.2024.11.010. Epub 2024 Dec 3. PMID: 39631181. Go to original source...
- James RL, Sisserson T, Cai Z, et al. Development of an FRα Companion Diagnostic Immunohistochemical Assay for Mirvetuximab Soravtansine. Arch Pathol Lab Med. 2024;148(11):1226-1233. doi: 10.5858/arpa.2023-0149-OA. PMID: 38282564. Go to original source...
- Státní ústav pro kontrolu léčiv. ELAHERE (mirvetuximab soravtansin): souhrn údajů o přípravku. Praha: SÚKL; 2025.
- Martin LP, Konner JA, Moore KN, et al. Characterization of folate receptor alpha (FRα) expression in archival tumor and biopsy samples from relapsed epithelial ovarian cancer patients: A phase I expansion study of the FRα-targeting antibody-drug conjugate mirvetuximab soravtansine. Gynecol Oncol. 2017 Nov;147(2):402-407. doi: 10.1016/j.ygyno.2017.08.015. Epub 2017 Aug 24. PMID: 28843653; PMCID: PMC6893864. Go to original source... Go to PubMed...
- Lawson BC, Marques-Piubelli ML, Westin SN, et al. Folate Receptor Immunohistochemical Staining and Gynecologic Tumors: Initial Experience With 216 Cases. Int J Gynecol Pathol. 2025;44(2):167-173. doi: 10.1097/PGP.0000000000001053. Epub 2024 Jun 12. PMID: 38914019. Go to original source...
- VENTANA FOLR1 (FOLR1-2.1) RxDx Assay Interpretation Guide for Epithelial Ovarian, Fallopian Tube, or Primary Peritoneal Cancer. 101522EN [Rev A. 2024]. Roche Diagnostics.
- Deutschman E, Fulton R, Sloss CM. Evaluation of Laboratory-Derived Immunohistochemical Assays for Folate Receptor α Expression in Epithelial Ovarian Cancer and Comparison With a Companion Diagnostic. Arch Pathol Lab Med. 2025;149(10):930-937. doi: 10.5858/arpa.2024-0210-OA. PMID: 40073910. Go to original source... Go to PubMed...
- Zannoni GF, Angelico G, d'Amati A, et al. Interobserver Agreement in Immunohistochemical Evaluation of Folate Receptor Alpha (FRα) in Ovarian Cancer: A Multicentre Study. Int J Mol Sci. 2025;26(16):7687. doi: 10.3390/ijms26167687. PMID: 40869006; PMCID: PMC12387075. Go to original source... Go to PubMed...
- Liang B, Tenney TB, Han L, et al. Heterogeneity and Scoring Reproducibility of Folate Receptor 1 Immunohistochemistry in High-grade Serous Carcinoma. Int J Gynecol Pathol. 2026;45(1):9-17. doi: 10.1097/PGP.0000000000001140. Epub 2025 Oct 6. PMID: 41217393. Go to original source...