Human cytosolic sulfotransferase SULT1E1 catalyzes the sulfation of estrogens and estrogenic drugs in human reproductive tissues. Logically, this estrogen-preferring sulfotransferase isoform could play a regulatory role in estrogen signaling activities in human reproductive cells, including the prostate cells. This hypothesis was tested using DNA microarray and real-time reverse transcription-polymerase chain reaction methods in the present work. Potential changes in the transcriptional expression of selected signal transduction-related genes in human prostate cancer CA-HPV-10 cell line after SULT1E1 transfection were examined by DNA microarray methods. Notable changes were observed in the mRNA expression levels of TFRC, a cell membrane transferrin receptor gene, and TMEPAI, a gene encoding a steroid-dependent mRNA product. Expression of TFRC was down-regulated, whereas expression of TMEPAI was up-regulated by SULT1E1 transfection in CA-HPV-10 cells. Data from the current studies also showed that the estrogen-induced estrogen response element activation in CA-HPV-10 cells was repressed after the cells were transfected with SULT1E1. These results indicate that SULT1E1 may function as a transcriptional mediator in human prostate cancer CA-HPV-10 cells.