Expression pattern of a five-gene model in prostate cell lines and tumors. (a) Hierarchical clustering of five genes, AR, PSA, CK5, uPA, and EphA2, in prostate cell lines. AR and PSA are two luminal cell markers, and CK5 is a basal cell marker. The resistant cell lines were separated from the majority of the sensitive cells (labeled in red) by these five genes. Note the high expression of CK5 and/or uPA, and EphA2 in sensitive cells and the nearly opposite expression pattern in resistant cells. (b) The expression pattern of these 5 genes in 52 prostate tumors. The gene expression of this published data set was profiled on Affymetrix HG-U95 gene chips. Two AR, three PSA probe sets and one CK5, uPA and EphA2 probe set are available on the chip and were retrieved for cluster analysis. The tumor samples exhibiting a dasatinib-sensitive pattern, that is, with low AR and PSA expression and high CK5 and/or uPA, and EphA2 expression are highlighted in red.