Enhanced polymer one-step staining for proliferating cell nuclear antigen in squamous cell carcinoma of the tongue

A rapid enhanced polymer one-step staining for proliferating cell nuclear antigen (EPOS-PCNA) in formalin fixed, paraffin embedded sections of tongue squamous cell carcinoma is described, EPOS-PCNA was compared with PCNA immunohistochemistry using the avidin-biotin complex (ABC) method, with or without autoclave pretreatment. Significant correlation of PCNA labeling index (percentage of labeled cells/total cells counted) was observed between EPOS-PCNA and the immunohistochemical protocol using autoclave pretreatment. We consider this method a reliable, timesaving technique that would be useful in quantitative histopathology and in performing double immunostaining.