Comparative ranking of EMT-associated genes with respect to fold-change differences in expression between the Group 1 and Group 2 primary and metastatic samples. Thirty-nine previously characterized EMT associated genes were identified among the 3,365 genes significantly differentially expressed across 14 tissue samples (see Figure 1). Histograms depict the fold change differences in expression between primary and metastatic samples of Group 1 (panel a) and Group 2 (panel b) patients. Although EMT-associated genes are more differentially expressed between primary and metastatic samples from Group 2 than Group 1 patients, Group 1 patients also display large fold differences for some EMT-associated genes. These findings suggest that the observed differences in expression of EMT-associated genes between the primary and metastatic samples of Group 1 vs. Group 2 patients represent differences in a continuum of the EMT-MET process rather than its occurrence in one and absence in the other.