Non-supervised hierarchical clustering of constituve genes regulated in un-irradiated lymphocytes. Clustering used Euclidean distance correlation and average linkage, and was processed and displayed with MultiExperiment Viewer http://www.tigr.org/tdb/microarray/. Upper panel shows a 20 gene set that segregated patients with different grade of acute toxicity (First three patients, grade 1; next five patients, grade 2; last four patients, grades 3–4) ANOVA test, p < 0.01. Lower panel shows a 26 gene set that segregated patients with different grade of late toxicity (First five patients, grade 2; last seven patients, grades 3–4) T-test, p < 0.01. The dendogram to the left of the heat map shows clustering of the genes. Accession number, gene symbol, gene description and fold change were added. Colour boxes indicate the biological process of each gene.