Antigen Retrieval Methods and Estrogen Receptor Immunoexpression Using 1D5 Antibody: A Comparative Study

The great importance that immunohistochem-istry has achieved as an ancillary tool to histologic diagnosis is due to its reliability and wide spectrum of applications. In fact, one can use the method in the differential diagnosis of anaplastic neoplasias, lymphoma diagnosis and phenotyping, search for primary sites of metastatic adenocarcinomas, prog-nostic evaluation of neoplasias, and microbiology diagnosis [1]. Morphology is necessary to make a good diagno-sis, and the use of formalin-based fixatives is the rule in anatomic pathology laboratories. Unfortu-nately, immunohistochemical methods ultimately depend on a good preservation of the specimen and therefore of the target molecule. Overfixation and underfixation are problems faced in everyday pathology laboratory routine. Formalin-fixed speci-mens are prone to overfixation, owing either to transportation delay or longstanding storing of the tissue before processing and embedding in paraffin wax. Long-term formalin tissue fixation results in antigen masking, probably through aldehydic link-age between proteins and fixative molecules [2,3]. Besides the fixation method and length, im-munohistochemistry results depend, by and large, on the type of detection procedure and the type of antibody used for the reaction. Polyclonal antibod-ies are more sensitive, while monoclonal antibodies are more specific. Different clones, which recognize different epitopes in 1 given molecule, have been used. In addition, experience shows that some type