Expression of the pS2 gene in breast cancer--a comparison of pS2 protein radioimmunoassay and immunohistochemistry.

pS2 expression was studied in a series of 82 primary breast carcinomas using and comparing a radioimmunoassay (RIA) technique and immunohistochemistry (IPOX). There was close correlation of the results obtained with each technique. Accurate and reliable determination of pS2 status in breast cancer can be made on the basis of immunohistochemistry using formalin fixed paraffin embedded sections. Immunohistochemical determination of pS2 status may be used in situations where the RIA technique cannot be applied, i.e. instances when fresh tumor tissue is not available.