FOLH1 and prostate carcinoma: However, PSMA is also expressed in other normal tissues such as salivary glands, bladder, pancreas, lung, kidneys, lacrimal glands, liver, spleen, intestines, celiac ganglion, and astrocytes.37–39 It is also seen in duodenal mucosa, some proximal renal tubule cells, some neuroendocrine cells in colon crypts, and some transitional cell, renal cell, colon, and other carcinomas.37 False negative scans have been seen in prostate cancer that has neuroendocrine differentiation, small size lesions, and lesions in close proximity to high physiologic uptake such as the celiac ganglia.40