Use of immunohistochemical staining for p16 in gynecological cytology

Role of immunocytochemistry in cervical cancer screening

The cervical cancer screening has been based conventionally on cytologic analysis. With advances in understanding the role of human papillomavirus, cotesting has been applied. But most of the patients subjected to colposcopy did not benefit, except in cases with HSIL [high-grade squamous intraepithelial lesion] cytology. Because of this, a step to increase the sensitivity to detect cancers and pre-cancers but with higher specificity with minimal overdiagnosis leading to prevention of unindicated cervical biopsies is highly desired. Such triaging step in cases with abnormal screening results is expected to minimize invasive interventions because of low false positivity. With availability of methodologies leading to quantitatively and qualitatively enhanced cell-blocks from residual liquid based cytology specimens, immunostaining can be performed for multiple immunomarkers with potential objectivity to triage initial screening test results. This is enhanced further with inclusion of AV marker in the cell-blocks and application of SCIP (subtractive coordinate immunoreactivity pattern) approach. The cell-blocks are also resource for performing other ancillary studies including molecular pathology and proteomics/metabolomics as potential tests in future. This review explores application of residual liquid based cytology specimen for cell-blocking with application of ancillary studies in algorithmic manner as adjunct to ASCCP management guidelines for improved patient care.