Based on limited published evidence, CLDN34 is a claudin family member localized to the plasma membrane at bicellular tight junctions. According to UniProt annotations, CLDN34 plays a major role in tight junction-specific obliteration of intercellular space through calcium-independent cell-adhesion activity. While direct functional studies of CLDN34 are absent from the provided literature, related claudins (CLDN3, CLDN4) are well-characterized tight junction proteins frequently overexpressed in cancers and involved in chemoresistance mechanisms 1. Claudins serve as targets for claudin-directed therapeutic approaches in cancer treatment 2.