The mRNA expression of the KDa stress-protein (SP) was assayed in normal and neoplastic human ovary. It was found that the expression level is low in normal ovary and in benign tumors and increases in the more advanced stages of ovarian cancer. A low level of mRNA coding for the 70 KDa SP--the most prominent among the inducible SPs-was constantly found in all specimens. No relationship was observed between SP 90 mRNA abundance and the receptor status of epidermal growth factor, estrogen and progesterone.