Prostate-specific immunostains (such as PSA, p501s and PSMA) are positive in only a minority of small cell carcinoma (approximately 20–25%) [[10],[11]] AR and NKX3-1 were not expressed in the majority of small cell carcinoma, although the majority of the concurrent acinar foci were positive for these markers [[2]]. The gene discussed is NKX3-1; the disease is small cell carcinoma.