Analysis of a 24-kilodalton (KD) protein in the human uterine cervix during abnormal growth

The authors have previously studied the presence and distribution of a 24-kilodalton (KD) estrogen-regulated protein in the human normal cervix (Am J Obstet Gynecol 1986; 155:1090-1096). This protein has recently been identified as a heat-shock protein, and in order to continue its study the authors have now examined its expression in preneoplastic to neoplastic cervical samples. The study involved 53 patients, the presence of 24-KD protein together with keratin and carcinoembryonic antigen (CEA) was investigated by immunohistochemical analysis. Cytosol samples from 15 patients with squamous cervical carcinomas were also studied by the Western blot technique, and the presence of estrogen receptors was analyzed biochemically. The 24-KD protein was observed in cervical intraepithelial neoplasias (CIN), but it was not useful to identify the different degrees of CIN examined. The 24-KD protein, keratin, and CEA were predominantly expressed in well and moderately differentiated squamous carcinomas in the more differentiated areas, and the protein was also found in cervical adenocarcinomas. The presence of 24-KD protein did not correlate with that of estrogen receptors in squamous cervical carcinomas. The Western blot and the immunohistochemical studies revealed that the antibody to 24-KD protein does not cross-react with epitopes of CEA and keratins.