The future of immunohistochemistry: genogenic immunohistochemistry

To date, immunohistochemistry has largely focused on markers of cell type, as an aid to the diagnosis of specific tumours. More recently, it has been applied to a limited number of markers of cell proliferation, such as Ki-67 and PCNA, as prognostic factors in malignant tumours.

In addition to the above, Gown1 identifies emergent uses of immunohistochemistry, coining the term genogenic immunohistochemistry. These are:

Examples include:

Identification of proteins expressed as a consequence of specific translocations. This relies on quantitative changes in the level of the protein: to date, no hybrid protein encoded by fusion genes is reliably detected by antibodies recognising unique junctional epitopes (that is, epitopes absent from the wild-type constituent proteins)2.
Examples include:
Identification of molecular targets for novel tumour therapies2
Identification of gene amplification and tumour therapy

 

There is the possibility that the molecular profiling of tumours, particularly where a large battery of genes needs to be tested, will be taken over by commercial enterprises, sidelining the surgical pathologist3.

References

1 A.M.Gown. Genogenic immunohistochemistry: a new era in diagnostic immunohistochemistry. Current Diagnostic Pathology 2002;8:193-200.

2 Falini, B., Mason, D. Y. Proteins encoded by genes involved in chromosomal alterations in lymphoma and leukemia: clinical value of their detection by immunocytochemistry. Blood 2002;99:409-26.

3 Giordano TJ. Molecular profiling and personalized predictive pathology: challenge to the academic surgical pathology community. Am J Surg Pathol 2006; 30:402-4

This page last revised 17.4.2006.

©SMUHT/PW Bishop