Synthesis of messenger RNAs for transforming growth factors α and β and the epidermal growth factor receptor by human tumors

Human tumors and tumor cell lines were analyzed for the presence of mRNA coding for transforming growth factors alpha and beta (TGF-alpha and -beta) and the epidermal growth factor receptor. TGF-alpha mRNA was not detectable in hematopoietic tumor cell lines but was found in a variety of solid tumor cells, particularly carcinomas. Many of the tumors that contained TGF-alpha mRNA also expressed high levels of epidermal growth factor receptor mRNA. The concentration of TGF-alpha in the media of several tumor cell lines did not necessarily correlate with TGF-alpha mRNA levels, as a substantial fraction of TGF-alpha can remain cell associated. The levels of TGF-beta mRNA in tumor cell lines and tumor specimens were variable, but higher in tumors than in the adjacent normal tissues.