Development of a novel enzyme-linked immunosorbent assay for the detection of cytokeratins 5, 8, and 18, and its implications in cervical cancer screening standardization

Abstract

There is a dire need for improved cervical cancer screening methods. New tests are in the pipeline, but their diagnostic capabilities may be limited without a way to assess specimen validity. Here we describe an enzyme-linked immunosorbent assay (ELISA) that captures specific intermediate filament proteins (cytokeratins) from potentially transformable target cells located within or originating from the cervical transformation zone as a means of cervical specimens. Seventy-five uterine cervical samples negative for human papillomavirus (HPV) were grouped based on microscopic analysis for the presence or absence of cervical transformation zone cells, and all samples were tested in both a newly developed recom Well Keratin 5/8/18 ELISA and a pan keratin control ELISA. Additionally, 15 samples from HPVpositive patients manifesting histopathologic lesions or squamous cell carcinoma were tested. Our results demonstrate the presence and detectability by ELISA of keratins 5, 8, and 18 in parabasal, squamous metaplastic, and endocervical cells, while simultaneously suggesting their absence in differentiated squamous cells. We also validate with ELISA the expression of these keratins in HPV-induced disease-state individuals. Our findings indicate recom Well Keratin 5/8/18 ELISA may be useful as a standardizing tool in cervical cancer screening, or alternatively as a quality indicator to denote specimen adequacy.