Estrogen receptors (ER) and progesterone receptors (PgR) were immunohistologically investigated in 107 patients with gastric cancer who underwent curative resection. Both ER and PgR were detected only in the cancer cell nucleus. The ER positive rate was 27.7% for males and 31.0% for females, while the PgR positive rate was 9.2% for males and 11.9% for females. Clinicopathologically, the ER positive rate was slightly higher in young females and in cases of poorly differentiated gastric cancer. When cumulative survival rates were analyzed in relation to the presence or absence of receptors, the 10-year cumulative survival rate after surgery was significantly lower in the ER positive cases, being 15.7% cent, than in the ER negative cases, being 62.7%, and also significantly lower in the PgR positive cases, being 18.2%, than in the PgR negative cases, being 48.3%. The coexistence of ER and PgR in gastric cancer tissues suggests that the ER is physiologically active, or that ER positive gastric cancer is hormone-dependent. The poor prognosis of patients with receptor positive gastric cancer suggests that gastric cancer with these receptors is highly malignant.

No abstract

Estrogen receptors (ER) were examined in cytosol, nuclear potassium chloride (KCl) extractable fraction, and nuclear KCl unextractable fraction by the dextran-coated charcoal adsorption method in various gastric cancer tissue. The overall ER-positive rate in the cytosol and nuclear fraction was 19.2%. The maximum binding site (Bmax) was 36.0 to 175.0 fmol/mg of protein, and the dissociation constant (Kd) was 0.6 to 1.6 X 10(-9) in cytosol fraction. In the nuclear fraction, Bmax was 7.5 fmol/mg of DNA and Kd was 2.3 X 10(-9). Estrogen receptors were characterized in cytosol protein. In cytosol, the estrogen (E2)-ER complex was sedimented at approximately the 5S and 8S regions by 5% to 20% linear sucrose gradient centrifugation. A steroid specificity study of ER showed the presence of an binder in gastric cancer tissue. In conclusion, these results that gastric cancer tissue has E2 binding sites with the same biochemical characteristics as in breast cancer and endometrial cancer strongly suggest the hormonal dependency of gastric cancer.

No abstract