Maspin protein expression : a special feature of papillary thyroid carcinoma

Abstract EN

Background and Aim : Mammary serine protease inhibitor (Maspin) is down regulated in breast and prostate cancers and is considered as a tumor suppressor gene.

On the contrary, it is over expressed in pancreatic and ovarian carcinomas and is reported to be an oncogene rather than a tumor suppressor gene.

The studies of maspin expression in thyroid neoplasia, the focus of this study, are limited.

We, therefore, carried out this work in order to detect the frequency and pattern of maspin expression in thyroid neoplasia.

Material & Methods : An immunohistochemical ap-proach was performed on 63 thyroid specimens showing different benign and malignant thyroid lesions.

Also, five specimens of the surrounding normal thyroid tissue were included as control.

A monoclonal anti-human antibody has been used to detect maspin.

Results : Maspin was only detected in papillary thyroid carcinoma (PTC) and it was negative in all other studied thyroid tissues.

In PTC 18 / 25 (72 %) cases were maspin positive.

Most of them 11 / 18 (61.1 %) showed both cyto¬plasmic and nuclear maspin expression, two cases 2 / 18 (11.1 %) were nuclear and the rest of the specimens, 5 / 18, (27.8 %) were cytoplasmic only.

There was no statistically significant relation between maspin positive cases and the studied clinicopathological parameters including patient's age, sex and tumor stage.

On the other hand, it was statistically significant as regards tumor multicentricity, vascular and lymphatic invasion, as well as lymph node metastasis.

Conclusions : Maspin expression is a special feature of papillary thyroid carcinoma (PTC) which can be used as a therapeutic target.

It may be suggested that the genesis of PTC may be different from other types of thyroid carcinoma.

Further studies regarding its prognostic role in patients with PTC are recommended.