These data indicate that (a) normal human mesothelial cells spontaneously express detectable levels of M-CSF mRNA in culture; (b) EGF is an essential cofactor for optimal induction of G-CSF and GM-CSF expression; (c) exposure of normal mesothelial cells to inflammatory mediators such as LPS and TNF increases the levels of transcripts for CSFs and IL-1 beta; and (d) as compared with normal human mesothelial cells, some cell lines of human malignant mesothelioma exhibit aberrant gene expression for multiple cytokines, including G-CSF, GM-CSF, IL-1 beta, and IL-6.