The immunoexpressions and prognostic significance of inhibin alpha and beta human chorionic gonadotrophins (HCG) in breast carcinomas

Abstract

Purpose: Pregnancy and hCG treatments are considered essential for inhibiting breast cancer. The effect of hCG is accompanied by the synthesis of inhibin, a transforming growth factor involved in cell differentiation and proliferation. Inhibin is considered a tumor suppressor, but its role in the breast is unclear. The aim of this study was to determine the frequency and tissue distribution of the expressions of inhibin-alpha and beta-hCG in breast cancer, and their prognostic relevance with other biological parameters.

Materials and methods: 334 of formalin-fixed, paraffin embedded tissue blocks were selected, and then immunostained for inhibin-alpha and beta-hCG. The inhibin-alpha expression was compared with those of beta-hCG, ER, PR and HER-2/neu, as well as the tumor characteristics and recurrences.

Results: Inhibin-alpha and beta-hCG were expressed in 87 (26.0%) and 44 cases (13.2%), respectively. Inhibin-alpha was found in 25.1% of infiltrating ductal carcinomas (67/267), 26.7% of intraductal carcinomas (8/30), 33.3% of lobular tumors (3/9), 80.0% of apocrine carcinomas (4/5) and 21.7% of the other types (5/23). Inhibin-alpha was correlated with beta-hCG (p<0.0001), PR (p=0.010) and HER-2/neu (p=0.021). HCG was focally expressed in the cytoplasm of the conventional types, but the apocrine type displayed diffusely intense cytoplasmic staining, which correlated with histological tumor types (p<0.001).

Conclusion: Inhibin was significantly correlated with the expressions of hCG, PR and HER-2/neu. Therefore, it might be a useful marker in the prevention and hormonal treatment of breast cancer, such as hCG and progesterone. HCG was expressed significantly higher in the apocrine type than the conventional types, suggesting it can be a useful adjunct in differentiating other cancer types.

Keywords: Breast neoplasms; Human chorionic gonadotrophin (hCG); Inhibins.

Fig. 1

A, B & C. Inhibin-α immunoreactivity was negative in the cytoplasm of (A) the normal ductal epithelial cells and (B) intraductal hyperplasia, but apocrine epithelial cells (C) showed a weak positive reaction (A, B & C: ABC immunostain, ×200).

Fig. 2

A & B. (A) Inhibin-α immunoreactivity showed negativity in a conventional ductal carcinoma, but (B) intense positivity in an apocrine carcinoma (A, B: ABC immunostain, ×200).

Fig. 3

A & B. (A) HCG immunoreactivity was focally expressed within the cytoplasm of the conventional type of tumor cells, but (B) the apocrine type displayed diffusely strong cytoplasmic staining (A, B; ABC immunostain, ×200).