Increased Expression of ALDH1A1 in Prostate Cancer is Correlated With Tumor Aggressiveness: A Tissue Microarray Study of Iranian Patients.

Subpopulations of prostate cancer (PCa) cells expressing putative stem cell markers possess the ability to promote tumor growth, maintenance, and progression. This study aimed to evaluate the expression patterns and clinical significance of putative stem cell marker aldehyde dehydrogenase 1 A1 (ALDH1A1) in prostate tumor tissues. ALDH1A1 expression was examined in a well-defined series of prostate tissues, including 105 (68%) samples of PCa, 21 (13%) samples of high-grade prostatic intraepithelial neoplasia, and 31 (19%) samples of benign prostate hyperplasia, which were embedded in tissue microarray blocks. The correlation of ALDH1A1 expression with clinicopathologic parameters was also assessed. There was a significant difference between the expression level of ALDH1A1 in PCa compared with the high-grade prostatic intraepithelial neoplasia and benign prostate hyperplasia samples (P<0.001). PCa cells expressing ALDH1A1 were more often seen in samples with advanced Gleason score (P=0.05) and high serum prostate specific antigen level (P=0.02). In addition, a positive correlation was found between ALDH1A1 expression and primary tumor stage and regional lymph node involvement (P=0.04 and 0.03, respectively). The significant association between ALDH1A1 expressions with Gleason score indicates the potential role of this protein in PCa tumorigenesis and aggressive behavior; therefore, this cancer stem cell marker can be used as a promising candidate for targeted therapy of PCa, especially those with high Gleason score.