Tenascin-C, a 6-armed extracellular matrix glycoprotein, is expressed in a temporally and spatially restricted pattern during tumorigenesis in association with stromal-epithelial interactions. We have previously shown that de novo synthesis of tenascin-C is induced by the diffusible factor EGF in tenascin-C-non-producing human epidermoid carcinoma cells in stromal-epithelial interactions. We now demonstrate that the addition of human tenascin-C or tenascin-C peptides to the culture medium of these cells had little effect on the induction of tenascin-C. The physiological regulators of tenascin-C induction through the EGF receptor, however, have not yet been characterized. We show that steroid hormones down-regulate EGF-induced tenascin-C glycoprotein and its mRNA in these tenascin-C-non-producing carcinoma cells. Of the steroids examined, hydrocortisone most effectively inhibited the secretion of tenascin-C. These steroids did not affect EGF-induced autophosphorylation or de novo synthesis of EGF receptors, nor did they compete for the binding of EGF to its receptor. Our results indicate that the induction of tenascin-C by EGF and its down-regulation by steroids might proceed in these carcinoma cells through separate signal transduction pathways.