Localization of estrone sulfatase in human breast carcinomas

We generated anti-human El-STS monoclonal antibodies to localize estrone sulfatase (El-STS) in human breast carcinomas. In particular, we examined the MCF-7 clone E3, ZR-75-1, MDA-MB 231, and MDA-MB-468 breast cancer cell lines and 25 breast carcinomas by either immunohistochemistry or Western blotting analysis. Simultaneously, we analyzed histological data, estrogen receptor (ER) status, progesterone receptor (PgR) status and epidermal growth factor receptor (EGFR) in breast tissue. All were surgical specimens from female patients. Nine of 25 carcinomas were obtained from premenopausal women, and 16 carcinomas were obtained from postmenopausal women. All cell lines demonstrated positive staining for El-STS. Interestingly, fine granulated staining of El-STS on the cell membrane was observed. In addition, Western blotting analysis detected a 65 kD protein with an El-STS specific band in all breast cancer cell lines regardless of the presence or absence of E2. Twenty-two of 25 (88.0%) carcinomas showed positive staining for El-STS, whereas negative staining was observed in the interstitial tissue surrounding tumors. In the premenopausal patients, 8 of 10 carcinomas (80.0%) showed positive staining for El-STS, whereas 14 of 15 carcinomas (93.3%) revealed positive staining in the postmenopausal patients. The frequency of El-STS expression was relatively higher in postmenopausal patients than in premenopausal patients but not statistically significant. The intensity of immunostaining for El-STS depended upon the size of the tumor (NS). There was no correlation between El-STS expression and other parameters. This evidence suggests El-STS expression may be involved in the development of breast cancer. Further studies are necessary to clarify the relationship between El-STS expression and prognostic factors. Immunoreactive El-STS may be localized in cancer cells but not in surrounding tissues in breast cancer.