Elevated cytokines and growth factors in GBM-M2 cells. Identification of cytokines and growth factors in common in the 24 hr conditioned medium for all three GBM-M2 tumor lines and the fold increases in their expression compared to the parental GBM cells. Heat map shows fold differences based upon the of expression ratios of 89 cytokines and proteins between parental and GBM-M2 lines determined as described in the materials and methods section. The fold change in protein expression level is indicated by color. GM-CSF, IL-6, IL-8 and BDNF were found highly elevated in all three GBM-M2 lines (fold changes are summarized in the supplementary table [Additional File 4]).