Evaluation of NMP179 for the detection of squamous intraepithelial neoplasia in ThinPrep cervical slides using a combination of double immunostaining and morphometric methods of analysis

This study investigates the potential value of the nuclear matrix protein NMP179 as a marker of abnormal squamous cells in ThinPrep slides. Forty-six cervical scrapes were collected as cell suspensions and ThinPrep slides were prepared. They were double-immunostained for NMP179 and Cytokeratin 18 (CK18), an endocervical cell marker. The method of analysis adopted for the study was designed to distinguish the abnormal squamous cells from benign epithelial cell so that the percentages of abnormal squamous cells that expressed the marker could accurately be determined. Initially, an attempt was made to identify benign and abnormal cells in the ThinPrep slides on the basis of their morphology and immunostaining patterns. Discrimination between the various types of epithelial cells was incomplete using this approach and a more precise method of discrimination between the different epithelial cell types was carried out using a combination of double immunostaining (NMP179 and CK18) and morphometry using nuclear area and nuclear cytoplasmic ratios. Once the different epithelial cell types had been identified, the specificity and sensitivity of NMP179 were determined. The optimal sensitivity (89.9%) was achieved at the N/C ratio 0.36; however, the specificity of NMP179 was very low for all N/C ratios and ranged from 38.8% to 42.2%.