Circulating levels of inhibin in cancer.

Study on frequency distribution of serum inhibin levels--a peptide hormone involved in suppression of follicle stimulating hormone--was carried out using a specific radioimmunoassay developed in this laboratory, on 237 sera from normal men and women, from male and female patients with cancer prostate, lung, stomach and breast, and from patients with non-malignant disease of the respective organ. The mean serum inhibin levels in patients with malignant and non-malignant disease of prostate (90 +/- 19 ng/ml and 54 +/- 8 ng/ml) were significantly higher than found in normal men (31 +/- 9 ng/ml). However, the levels in cancer of stomach (70 +/- 9 ng/ml) and lung (45 +/- ng/ml) were higher than those in normal as well as benign condition of stomach and lung. The mean serum inhibin in case of women with cancer of breast (27 +/- 5 ng/ml) and lung (53 +/- 16 ng/ml) were significantly higher than those found in normal women (15 +/- 2 ng/ml) and in women with benign disease of breast (10 +/- 3 ng/ml) and lung (21 +/- 4 ng/ml). Considering the levels in individual patient basis, 66% of the patients with cancer of stomach had higher inhibin concentration than the uppermost limit of inhibin found in normal men and in contrast none in benign disease of stomach.