While 62 proteins were shared by exosomes from endometriosis patients and controls irrespective of menstrual phase, five proteins were found exclusively in endometriosis samples: (fragments of) PRDX1, histone H2A type 2-C, ANXA2, ITIH4 (fragment), and tubulin α-chain. The gene discussed is ITIH4; the disease is endometriosis.