As mentioned however, many groups have reported the continuous expression of AR and activation of the AR-androgen signaling pathway in castration-resistant prostate cancer through both in vitro as well as in vivo studies despite the androgen castrated environment, supporting the existence of an intracellular de novo androgen synthesis pathway rather than the tumor’s ability to sustain itself despite the lack of androgens [24-27]. The gene discussed is AR; the disease is neoplasm.