Used in targeted cancer immunotherapy, particularly for tumors expressing CLDN6 (Claudin 6), such as certain testicular, ovarian, and endometrial cancers. Acts as a binding agent to deliver cytotoxic payloads directly to CLDN6-positive cancer cells when conjugated to drugs or used in bispecific antibody formats. Enables selective recognition of tumor cells, minimizing damage to healthy tissues. Also serves as a research tool for validating CLDN6 as a biomarker and for developing CAR-T cell therapies targeting CLDN6-expressing malignancies.