The EGFR Amplification probe consists of a red 295kb probe spanning the gene region 7p11.2. The centromeric probe in green acts as a control for chromosome 7.
The EGFR (previously known as HER1), Epidermal Growth Factor Receptor, gene on chromosome band 7p11.2, is a type 1 tyrosine kinase receptor for members of the epidermal growth factor family. Binding of the EGFR and epidermal growth factor proteins leads to cell proliferation1.
Abnormally elevated EGFR kinase activity can lead to proliferative diseases such as non-small-cell lung carcinoma (NSCLC), which accounts for 80-85% of all lung cancers2, and less frequently breast cancer3, amongst others.
There are three small molecule EGFR kinase inhibitor drugs in clinical use (gefitinib, erlotinib and lapatinib) and several others that are currently undergoing clinical development4. Approximately 10% of lung cancer patients show a rapid and dramatic response to these Tyrosine Kinase Inhibitors (TKIs)5,6.
FISH has proven to be useful for determining the amplification status of EGFR in NSCLC and has therefore aided in the selection of patients for treatment with EGFR TKIs7.