ACTG2 and Familial prostate cancer: Further examination of differential expression of the genes that harbor the eight candidate STRs using the Taylor et al. microarray study23 confirmed our observations that TRIB1, PCA3, and GRHL2 are over-expressed in prostate cancer, and that ACTG2, GSN, and MXI1 are down-regulated in prostate cancers (Fig. 3c).