Acts as androgen receptor coregulator that increases androgen receptor activity by modulating the receptors interdomain interaction. May play a role in embryonal development and tumor transformation or aspects of tumor progression. Expressed in tumors of several types, such as melanoma, head and neck squamous cell carcinoma, lung carcinoma and breast carcinoma. Expressed in testis, ovary, prostate, cancerous prostate, breast and adrenal tissue.