**Background of FOLR1 Antibodies**
Folate receptor alpha (FOLR1), a glycosylphosphatidylinositol (GPI)-anchored membrane protein, facilitates cellular uptake of folate and its derivatives by mediating receptor-mediated endocytosis. FOLR1 is overexpressed in various malignancies, including ovarian, endometrial, lung, and breast cancers, while exhibiting limited expression in normal tissues. This tumor-selective expression makes FOLR1 a promising therapeutic and diagnostic target.
FOLR1-targeting antibodies are engineered to exploit this specificity. Therapeutically, they are utilized in antibody-drug conjugates (ADCs) or bispecific antibodies to deliver cytotoxic payloads or engage immune cells directly at tumor sites. For example, mirvetuximab soravtansine, an FOLR1-directed ADC, has shown efficacy in platinum-resistant ovarian cancer. Diagnostically, FOLR1 antibodies aid in immunohistochemical detection of FOLR1 expression to guide treatment eligibility.
Research highlights FOLR1's role in cancer progression, including folate metabolism dysregulation and potential resistance to conventional therapies. However, challenges like heterogeneous FOLR1 expression across tumors and on-target toxicity in folate-rich tissues (e.g., kidneys) necessitate optimized antibody designs. Current studies focus on improving tumor penetration, reducing immunogenicity, and combining FOLR1-targeted therapies with checkpoint inhibitors or chemotherapy. These efforts aim to expand clinical applications and overcome resistance mechanisms in FOLR1-positive cancers.