Fascin expression in low-grade uterine endometrioid adenocarcinoma: correlation with microcystic, elongated and fragmented (MELF)-type alteration at the deep invasive margin

Abstract

The actin-binding protein fascin appears to potentiate the migratory capacity of both normal and neoplastic cells. It has been suggested that microcystic, elongated and fragmented (MELF) glands might represent areas of active invasion within uterine low-grade endometrioid adenocarcinomas. Therefore, fascin immunoreactivity was investigated in a series of endometrial carcinomas specifically comparing expression in conventional tumour areas, foci of MELF-type invasion and in stromal elements. Fascin expression was assessed in 28 uterine endometrioid adenocarcinomas and the results compared with cytokeratin (CK) 7 expression and with tumour morphology and distribution. The conventional glandular component of most tumours showed only focal fascin reactivity (<10% cells positive), but staining was more prominent within the peripheral epithelial cells. Foci of squamous/morular type differentiation were also positive. The neoplastic epithelium in MELF-type invasion usually showed strong fascin immunoreactivity, often contrasting with the adjacent negative or more weakly stained conventional tumour glands. There was also staining of reactive stromal cells surrounding MELF foci. There are distinct micro-anatomical variations in fascin immunoreactivity within endometrial carcinoma. The localized increase in fascin expression in MELF-type epithelium supports the proposal that MELF changes represent areas of active tumour invasion.