Fig 1: Western blot of OPN, CA 125, HE4, and TTR from human urine.A representative western blot of Osteopontin (OPN), CA125, HE4, and transthyretin (TTR) antigens expressed in protein lysates obtained from concentrated human urine samples from healthy individuals is depicted. Anti-Osteopontin, HE4, and TTR antibodies detected a single protein isoform of the corresponding proteins. Osteopontin migrated with an apparent molecular mass of 60 kDa, HE4 protein fragment migrated at 13 kDa, and TTR at 15 kDa. Anti-CA125 antibody detected three different protein fragments. The major CA125 fragment migrated in SDS-PAGE with an apparent molecular mass of 41 kDa (shown) and two smaller protein bands were in the range of ~ 28–30 kDa. The presence of the different CA125 protein fragments in the human urine samples was confirmed by immunoblotting using various anti-CA125 antibodies. THP (68 kDa band) was evaluated as a loading control.