Identification of a gene signature changed by gemcitabine and Wee1 inhibitor in rat skin sample. (A) Expression profile of rat skin samples treated with gemcitabine and Wee1 inhibitor. Nude rats were administered with gemcitabine and increasing concentrations of the Wee1 inhibitor via IV infusion. At 8 hr post Wee1 inhibitor administration, mRNA from each rat skin sample was applied to microarray analysis. A gene signature whose expression significantly changed in response to gemcitabine and Wee1 inhibitor treatment was extracted. Each row represents a sample from each treatment group. Each column represents a gene. Red, up-regulated genes; green, down-regulated genes. (B) Wee1 gene signature commonly changed in both cancer cell lines and skin samples. The common signature for both tumor and surrogate tissues was identified by extracting commonly regulated genes in global expression profiling. Gem: gemcitabine; Wee1i: Wee1 inhibitor (MK-1775).