Gene expression microarray assay

VCaP or VCS2 cells treated with ethanol or 10nM DHT were subjected to microarray assay (Affymetrix) to identify genes whose expression was repressed by DHT in both VCaP and VCS2 cells. Tissue mRNA was extracted and purified from three sets (pre-castrated, 4d-post-castrated, and relapsed) of xenograft tumors (3 mice) and then subjected to microarray assay (Agilent). SAM software was used to perform t-test on these three biological repeats (three mice) to determine the score and q-value. The genes whose expression was significantly elevated in relapsed tumors (q<0.05) were picked for the next screening to determine if they were DHT-repressed in VCaP and VCS2.