Immunohistochemical markers, are we having too many choices?

Abstract

As more and more antibodies are made available for immunohistochemical studies, pathologists are increasing being challenged to make a rational choice from multiple antibodies all of which are reputably suited for the same or similar diagnostic application. A recent review was conducted into the practice of a group of histopathologists working in a general teaching hospital in how they had used the three antibodies, namely smooth muscle actin, calponin and p63, each of which could be used as a marker for myoepithelial differentiation. The findings are presented and discussed. Immunohistochemical studies recently carried out in the histopathology laboratory of the Queen Mary Hospital, Hong Kong were recorded in a computerized database. The database was searched for all stains performed for actin, calponin, and p63 from Jan 2005 to the end of April 2007. Parameters selected were the accession number complete with the tissue block number, antibodies stained and the pathologist ordering the stains. A total of 1148 blocks were stained for actin (n=803), calponin (n=127), and p63 (n=574). Pathologists varied widely in their choice of applying these antibodies. While it is uncommon to use all 3 antibodies on a single block (n=38), one pathologist alone was responsible for 76% (n=29) of this usage. Slightly more blocks were stained for p63 alone (n=291) then those stained in combinations with actin and/or calponin (n=283). Significant variation in the use of the 3 antibodies was observed among a group of 24 pathologists working in a single public institution. Stereotypic patterns of applying immunohistochemical stains may result in excessive procedures. A system to monitor and provide timely feedback on the usage of immunohistochemical markers with the adoption of common protocols would effect cost cuts and more efficient running of laboratory services.