Jurkat (human T-cells), WI-38 (human fibroblasts), DO11.10 (mouse T cells), and C3H10T1/2 (mouse fibroblasts) were exposed to 836.5 MHz (CDMA) at up to 36.5 W/kg and 1.765 GHz (CDMA) at up to 38.2 W/kg for up to 72 hours. Initial data presented at Korean Meeting on EMF Bioeffects (2002) and the WHO Meeting on EMF Biological Effects, Seoul, Korea, (2001) reported these thermal levels had a different effect on the expression profile using 5K and 10K genechips than that produced by ionizing radiation, with a decrease in genes related to metabolism, a decrease in genes repated to protein biosynthesis, and increase in genes related to differentiation, a decrease in signal kinase gene expression, and changes in stress response genes. At the highest level of exposure, actin polymerization as well as signal transduction and transcription factor gene expression profiles were increased and cytokine and metabolism gene expression profiles were decreased. RF exposure at thermal levels did not cause any gross morphological, cellular, or proliferation changes. When human T-lymphocyte Jurkat cells and rat primary astrocytes were exposed to 1,763 MHz at SARs of 2 or 20 W/Kg, for 30 minutes or 1 hour, with temperature maintained at 37 +/- 0.2 C, there were no detectable changes in HSP90, HSP70, and HSP27 protein levels. No effects were observed in phosphorylation status of MAPKs ERK1/2, JNK1/2, or p38. Exposure at these levels also did not synergize with TPA in MAPK phosphorylation. Neither TPA nor RF radiation exerted any detectable effect on induction of HSPs. In a similar study using a 1763 Mhz expsoure at 2 or 10 W/kg, the authors report no effect on proliferation, cell cycle progression, or DNA damage via comet assay. No changes in gene expression above 2-fold were detected using gene chip arrays. Of the handful of genes changed between 1.3 - 2 fold, two were cytokine receptors that the authors feel should be investigated further. From the data, however, they conclude "... no significant evidence of alternation in cell proliferation, cell cycle progression, DNA integrity, or global gene expression". In a study of HEI-OC1 cultured mouse auditory hair cells exposed to 1763 MHz (CDMA) RF at 20 W/kg for 2 or 4 hours, the authors report no changes in cell cycle progression using flow cytometry, DNA damage via comet assay, phosphorylation of the MAPK proteins Erk1/2, Jnk1/2, and p38, or overall gene expression using microarray analysis.