(A) Immunohistochemical determination of ZIP 1 transporter levels in normal and malignant prostate glands. The strong positive reaction is evident in the normal gland secretory epithelial cells that border the lumen, and is virtually absent in the malignant glands. Note that ZIP1 is not apparent in the stroma. (B) RT-PCR of RNA extracted from malignant prostate tissue and benign prostatic hyperplasia. Note the marked decrease in ZIP1 mRNA in the malignant tissue. Results are representative of two independent samples. Density of the bands was determined by densitometry scans and GAPDH band intensity used to normalize hZIP1 mRNA. hZIP1/GAPDH for PCa and BPH were 0.71 ± 0.067 and 1.02 ± 0.092 respectively. (C) Immunohistochemical detection of ZIP1 in malignant prostate cell lines. Note the association of ZIP1 with the plasma membrane.