Metallothionein expression and nuclear size-in benign, borderline, and malignant serous ovarian tumours

Metallothioneins (MTs) are low-molecular-weight proteins involved in metall oregulatory functions such as cell proliferation, growth, and differentiati on. In recent years, MT expression has been linked with carcinogenesis, res istance to cancer therapy, and tumour progression. However, the significanc e of MT expression in ovarian cancers is at present inadequately documented . In this study, MT immunohistochemistry was performed in 12 benign, 14 bor derline, and eight malignant serous tumours of the ovary. The intensity of the immunostaining was evaluated by image analysis. There was a significant ly higher number of MT-immunopositive cells in the multilayered epithelial cells of borderline serous tumours (atypical proliferative serous tumours) than in the single layered epithelial cells within the same tumour, and in the single cell layer of benign serous tumours. There was no difference in the expression of MTs in the single layered tumour cells of benign and bord erline serous tumours. Significantly higher numbers of MT-immunopositive ce lls were observed in both the single and the multilayered epithelial cells of serous carcinomas, the highest number being observed in the multiple lay ers of serous carcinomas. The positively stained malignant tumour cells in both single and multiple layers were larger than the negatively stained cel ls in benign, borderline, and malignant serous ovarian tumours. There was m oderate to intense staining. These findings indicate that there is increase d expression of MTs in the progression of malignancy, which could be used a s a marker in grading the three groups of ovarian serous tumours and for de termining prognosis. Copyright (C) 1999 John Whey & Sons, Ltd.