SOX-9 is a protein that in humans is encoded by the SOX9 gene. It is expressed by proliferating but not hypertrophic chondrocytes that is essential for differentiation of precursor cells into chondrocytes and, with steroidogenic factor 1, regulates transcription of the anti-Müllerian hormone (AMH) gene. The Sox-9 protein has also been implicated in both initiation and progression of multiple solid tumors. Its role as a master regulator of morphogenesis during human development makes it an ideal candidate for perturbation in malignant tissues. Specifically, Sox9 appears to induce invasiveness and therapy-resistance in prostate,[16] colorectal, breast and other cancers, and therefore promotes lethal metastasis. Many of these oncogenic effects of Sox9 appear dose dependent.