The neuromedin B receptor, a Bombesin Receptor, activates phospholipase and protein kinase C and enhances calcium mobilization. It binds neuromedin B, a potent mitogen and growth factor for normal and neoplastic lung and for gastrointestinal epithelial tissues. Neuromedin B receptor expression has been reported in brain, particularly the olfactory bulb and thalamus, and in colon, liver, placenta, testis, spinal cord, and gastrointestinal tract. In addition, it has been shown to be present in cancer of the lung, ovary, and prostate. ESTs have been isolated from B-cell/lung/testis and brain libraries.