70 gene signature correlation values. The 70-gene signature correlation values for the four tumors were determined for each hybridization; these values indicate the correlation of the log ratios of the 70 signature genes from the tumor sample with the average log ratios from a previously defined set of patients . The correlation values for each dye-swapped pair (y-axis) are plotted for each of the four tumors (x-axis). Red data points were labeled in Amsterdam, while blue data points were labeled in California. The mean and standard deviations of the correlation values for each tumor are indicated beneath the plot. Each set of hybridizations for each tumor was divided into two groups, based either on hybridization site, labeling site, or hybridization day. An ANOVA was then performed on the 70 gene signature correlation values obtained in the hybs for both groups, and the resulting P values for each tumor are shown.