History of Testing for HER2: Timeline
- Western blot: Used on homogenized tissue in the late 1980s.
- Southern blot: Gene amplification was initially detected by Southern blot in frozen tumor specimens and was subsequently found to correlate with overexpression at the mRNA and protein levels.
- Enzyme-linked immunosorbant assay (ELISA): Used on homogenized tissue or blood late in 1980s, the mid-1990s, and in the mid-2000s.
- Immunohistochemistry (IHC): Used on tissue sections, first on frozen sections and later on paraffin sections. Throughout the years, several clones have been used such as clone 4D5 and clone CB11, with vast improvements in recent years owing to standardization of IHC.
- Fluorescence in situ hybridization (FISH): Used on tissue sections in the early 2000s.