D ‐ PCa ‐ 2 : A novel transcript highly overexpressed in human prostate and prostate cancer

Identification of genes selectively expressed in tumors or individual tissues is a crucial prerequisite for molecular diagnosis and treatment of cancer by addressing molecular targets. By screening an expression database, we identified the novel gene D ‐ PCa ‐ 2 (Dresden prostate carcinoma 2), which is highly overexpressed in normal prostate tissue and prostate carcinoma (PCa). The corresponding transcript contained an open reading frame of 453 nucleotides encoding a putative protein of 150 amino acids. A large part of exon 8 of the D ‐ PCa ‐ 2 gene shows strong similarity to the high‐mobility‐group nucleosomal binding protein 2 (HMGN2) cDNA. The highly specific transcription of the D ‐ PCa ‐ 2 gene in normal and malignant prostate tissues and in a few additional tumors was demonstrated by using multiple tissue dot blot, cancer profiling dot blot and real‐time PCR analyses. Examination of 18 pairs of tumorous and nontumorous prostate tissues from PCa patients by quantitative RT‐PCR revealed D ‐ PCa ‐ 2 transcripts in all specimens. The potential usefulness of D ‐ PCa ‐ 2 as a sensitive marker for metastatic prostate carcinoma cells in lymph nodes was demonstrated by the detection of one LNCaP cell in 1 × 10 5 normal lymph node cells using real‐time RT‐PCR. Examination of 22 lymph nodes from PCa patients either containing metastatic prostate cancer cells or diagnosed as cancer‐free was in full concordance with histopathologic diagnoses. These results validate D ‐ PCa ‐ 2 as a transcript with high tissue specificity and with a potential application in the diagnosis of PCa. © 2004 Wiley‐Liss, Inc.