Correlation between cytoplasmic steroid receptors and tumour differentiation and invasion in endometrial carcinoma

Interferon-beta can induce progesterone receptors in human endometrial adenocarcinoma

BACKGROUND

The induction of estrogen and progesterone receptors (ER and PGR) has been reported in breast and endometrial cancer cells exposed to human fibroblast interferon-beta (hIFN-beta). Clinical verification of this finding might provide the rationale for new therapeutic approaches. This study was designed to evaluate whether clinical treatment with high doses of hIFN-beta induced ER and PGR in patients with endometrial adenocarcinoma.

METHODS

Two biopsies were obtained, 1 before and 1 after hIFN-beta treatment (3 x 10(6) i.m. every other day for 3 weeks) from 36 patients with endometrial adenocarcinoma. ER and PGR were determined with standard procedures using radiolabeled ligands.

RESULTS

hIFN-beta treatment did not affect the proportion of ER-positive (i.e., >15 fmol/mg protein) or PGR-positive (i.e., >20 fmol/mg protein) cases. However, in patients with detectable ER and PGR at baseline, hIFN-beta raised the levels. Using a 35% difference before and after therapy as a cut-off, 72 and 79% of cases had increases in ER and PGR, respectively. The difference was highly significant for PGR.

CONCLUSIONS

In patients with endometrial adenocarcinoma with undetectable ER or PGR, hIFN-beta did not induce the expression of these receptors. When the receptors were present they were upregulated by hIFN-beta. Whether this increase in receptor levels, particularly PGR, has therapeutic applications remains to be established.

A randomized trial of adjuvant progestagen in early endometrial cancer

A randomized, controlled trial was designed to determine whether adjuvant progestagen therapy improves survival in patients with Stage I or Stage II endometrial cancer. After surgery, 1148 patients were randomly assigned to adjuvant treatment with progesterone or were given no additional therapy. The duration of follow-up ranged from 42 to 132 months (median follow-up, 72 months). Crude survival and relapse rates were similar for both groups. Death due to intercurrent disease was higher in the progesterone group (P = 0.04). The median survival of the group of patients with cancer-related death was higher in the progestagen group than in the control group (30 and 22 months, respectively; P = 0.03). In 461 high-risk patients, a tendency towards fewer cancer-related deaths and a better disease-free survival in the treatment group was observed, but crude survival was unchanged. We conclude that there is little to gain from adjuvant progestagen therapy in patients with low-risk endometrial cancer, and that further studies are needed in high-risk patients.

Epidermal growth factor receptors in human breast and endometrial carcinomas

The incidence and levels of epidermal growth factor receptor (EGFR) were studied in 67 breast tumors and 22 endometrial carcinomas. Estrogen receptors (ER) were also measured in all samples and progesterone receptors (PR) were analyzed in 57 breast samples and 21 endometrial tumors. A high level of EGFR expression is found in both breast and endometrial carcinomas, although the incidence of EGFR content is greater in breast carcinomas. 36% of breast tumors had EGFR at levels 3-49.5 fmol/mg membrane protein, whereas this percentage of positivity was 27% for endometrial tumors. In 51% of breast carcinoma and 73% of endometrial tumors, there was a positive ER content, whereas 53% of breast tumors and 62% of endometrial carcinomas were positive. A clear inverse relationship between EGFR content and ER and PR status has been observed in breast tumors. Our data confirm the previously described inverse correlation between expression of EGFR and estrogen receptors in human breast cancer. We also show here that there is a similar inverse relationship between EGFR content and ER levels in endometrial tumors.

Progesterone receptor heterogeneity and endometrial tumour differentiation

Progesterone binding components were isolated using fast protein liquid chromatography (FPLC) with a recovery efficiency of between 60-70%. In normal uterine cytosol, the two components were in about equal proportions. In endometrial cancer, the ratio of peak size between peaks 1 and 2 was 1.5 for Grade I, 3.7 for Grade II and 2.5 for Grade III. Whether estimation of the levels of the two progesterone components separately would enhance predictability of response to hormone therapy in endometrial cancer remains to be established.

Immunohistological localization of pregnancy-associated endometrial alpha 2-globulin (alpha 2-PEG) in endometrial adenocarcinoma and effect of medroxyprogesterone acetate

Endometrium from postmenopausal women with endometrial adenocarcinoma was examined immunohistochemically using a monoclonal antibody to pregnancy-associated endometrial alpha 2-globulin (alpha 2-PEG), the major secretory protein of the glandular epithelium during the late luteal phase of the menstrual cycle and early pregnancy. Specimens were obtained at initial diagnostic curettage and at hysterectomy after medroxyprogesterone acetate (MPA) therapy. alpha 2-PEG was not detected in any malignant tissue irrespective of histological differentiation. Non-malignant endometrium obtained in association with malignant tissue was negative for alpha 2-PEG before treatment although after MPA therapy all specimens obtained exhibited marked alpha 2-PEG localization in glands. In four specimens endogenous alkaline phosphatase was observed consistently only in the malignant endometrium. Malignant endometrium does not appear to synthesize alpha 2-PEG nor is its synthesis induced by an oral progestogen, so that it does not represent a useful marker for endometrial carcinoma. Non-malignant endometrium in postmenopausal women appears to be fully capable of alpha 2-PEG production after stimulation with an oral progestogen.

Estrogen and progestin receptor levels as prognosticators for survival in endometrial cancer

The survival of 213 postmenopausal patients with primary endometrial cancer was analyzed as a function of clinicopathologic features and cytosol steroid receptor levels. Estrogen receptor (ER) levels (P = 0.008) and progestin receptor (PR) levels (P = 0.0001) were negatively correlated with grade. ER and PR levels were positively correlated with each other (P = 0.0001), but neither was correlated with age. In 187 patients with stages I and II, ER positivity (greater than or equal to 20 fmole/mg cytosol protein (cp] was statistically associated with grade (P = 0.007); and PR (greater than or equal to 7 fmole/mg cp) was statistically associated with grade (P = 0.001). Univariant analysis revealed that survival for the early endometrial cancer patients was significantly dependent upon ER status (P = 0.0003), PR status (P = 0.0016), and grade (P = 0.0002). Multivariant analysis of ER status, PR status, age, and grade showed that the ER status was a significant prognostic factor for survival (P = 0.0168), even if the positivity of the PR status was defined at greater than or equal to 50 fmole/mg cp. If ER status was divided at 0-19, 20-100, and greater than 100 fmole/mg cp, survival was significantly different between the low range group and the other two groups. If PR status was divided at 0-6, 7-50, and greater than 50 fmole/mg cp survival was significantly different between the first two groups and the high range group. Thus, survival in these endometrial cancer patients was better predicted by ER status than grade.