The effects of a short period of in vivo systemic rh-IFN-alpha/2b treatment on epidermal-growth-factor(EGFR)-, estrogen(ER)- and progesterone(PR)-receptor content in 11 primary human cervical tumors was investigated by the radioreceptorial technique. EGFR levels were found to be significantly higher in cervical tumors after rh-IFN-alpha/2b treatment with respect to basal levels. In 2 cases, immunohistochemical and cytofluorimetric analysis showed that rh-IFN-alpha/2b treatment induces an increase in EGFR immunoreactivity and in the fraction of EGFR-positive cells. No difference in ER and PR levels in cervical tumors before and after rh-IFN-alpha/2b treatment was observed. Our results suggest that rh-IFN-alpha/2b up-regulates EGFR in primary human cervical tumors in vivo.