High metallothionein expression is associated with features predictive of aggressive behaviour in endometrial carcinoma

Aims: Metallothioneins (MTs) are a group of ubiquitous low molecular weight proteins with a high affinity for heavy metal ions. The aim of the present study was to investigate MT expression in a series of endometrial carcinom as. We wished to determine whether MT expression in endometrial carcinoma w as related to established prognostic factors such as tumour grade, stage an d histological type. We also wanted to establish if high MT expression in c urettings of endometrial carcinoma was predictive of high expression in the subsequent hysterectomy specimen, Methods and Results: Sixty-three cases of endometrial carcinoma were includ ed in the study, These comprised 57 endometrioid adenocarcinomas (15 grade 1, 25 grade 2, 17 grade 3), three papillary serous adenocarcinomas, two muc inous adenocarcinomas and one clear cell adenocarcinoma. Forty-five tumours were stage I, 10 were stage II and eight were stage III. In 28 cases, diag nostic endometrial curettings, performed prior to hysterectomy, were availa ble for study. Immunohistochemical staining was performed using the anti-MT monoclonal antibody E9. The intensity and distribution of MT staining were assessed using a semiquantitative method. This resulted in an intensity di stribution (ID) score out of a maximum of 300. The mean ID score of grade 1 and 2 endometrioid adenocarcinomas was 67 and 63, respectively, while for grade 3 tumours the mean ID score was 114. This was statistically significa nt (P = 0.05). The three papillary serous adenocarcinomas had high ID score s with a mean of 208. The mean ID score of stage I tumours was 69, This was lower than those of stage II and LII tumours which had mean ID scores of 1 16 and 128, respectively. However, these differences were not statistically significant (P = 0.288). A significant correlation was observed between MT ID scores in endometrial curettings and in the subsequent hysterectomy (P = 0.013). Conclusions: MT isoforms can be demonstrated in most endometrial adenocarci nomas. High MT ID scores are associated with high grade and high stage endo metrial adenocarcinomas and with the aggressive papillary serous adenocarci noma, Whether this is of value as an independent prognostic factor has yet to be established.