Cluster and pathway analysis of basal gene expression in FaDu, NCI-H522, MDA-MB-231, MCF7, PC-3 and HT-29 tumor cell lines. (a) Clustering analysis of the tumor cell lines indicated close clustering for FaDu and PC-3, followed by MDA-MB-231 and NCI-H522, while MCF7 and HT-29 did not cluster readily with the group. Clustering analyses were performed on differentially expressed genes in FaDu and PC-3 relative to MCF7 and HT-29. (b) Cytokine and inflammatory response pathway was among the top enriched pathways in differentially expressed genes between FaDu and PC-3 relative to MCF7 and HT-29. (c) Genes in the cytokine and inflammatory response pathways from b and their expression levels are shown. (d) mRNA expression level of IL1β in different tumor cell lines from the microarray data. (e) Quantification of secreted IL1β by ELISA from different tumor CM. Data are presented as mean ± S.D. n = 3. CM, conditioned media.