Expression of macrophage migration inhibitory factor in the human prostate

The expression of macrophage migration inhibitory factor (MIF) in prostate tissue was investigated by immunohistochemistry (IHC), enzyme-linked immunosorbent assay (ELISA), and Northern blot analysis using a prostate tissue bank. MIF expression was examined in each of the following established prostate tissue categories: prepubertal, pubertal, adult normal, benign hyperplastic (BPH), focal carcinoma within the prostate, and metastatic prostate cancer. IHC showed that all samples tested were positive for MIF protein, which localized to the glandular epithelial cells with no apparent staining of stroma. The most intense staining was observed in the metastatic prostatic adenocarcinoma and the human prostatic adenocarcinoma cell line LNCaP. Using quantitative ELISA, MIF expression was found to be at least three times higher in metastatic adenocarcinoma than in normal, BPH, or focal carcinoma in the adult prostate. This study is the first to report that prostate glandular epithelial cells express MIF. The exact role of MIF in prostate development and disease progression requires further study.