Quantitative RT-PCR validation of selected genes. A) Hierarchical clusters built using microarray data corresponding to the 45 genes selected for Q-PCR validation. T, N, S and CL are as described in Fig. 1. B) Hierarchical sample and gene cluster generated with Q-PCR data for genes showing concordance with microarray data (either upregulated or downregulated in both determinations) in 4 normal-tumoral non-microdissected matched samples and 7 normal-tumoral microdissected matched samples. C) Graphical representation of the Q-PCR tumoral/normal ratios for the 26 genes showing the best concordance with microarray data (9 overexpressed and 17 underexpressed in tumoral vs. normal samples). Shown are the averages for each of the selected genes of the Q-PCR tumoral/normal ratios for microdissected epithelia (light gray bars) and for whole, non-microdissected tissues (dark gray bars).