A new protein being studied as a possible diagnostic biomarker in patients with PCOS is insulin-like peptide-3 (INSL3), which is released from theca cells of the follicles, the corpus luteum, and ovarian stroma and the levels of which increase at the onset of puberty, like insulin, IGF-1, and IGF-BP3. The gene discussed is INSL3; the disease is polycystic ovary syndrome.