Question

How does cancer result from defects in the EGF activated signal transduction pathway?

Answer 1

There are a plethora of cellular signaling which works in orchestration with one another to help the cell maintain its normal cellular homeostasis. Among those cellular signaling, one of them is EGF (Epidermal Growth Factor) signaling. For every signaling pathway, there is a receptor that is activated by the ligand and this activation signal gets amplified by signaling intermediates to perform a particular function. EGF signaling pathway is responsible for many basic cellular functions like adhesion, migration, survival, etc. EGF binds at the receptor EGFR on the cell surface and activates the signal transduction pathway. There can be two possibilities by which EGF signaling can go out of control of the cell and can hamper cellular homeostasis.

1. Overexpression of EGFR- If the transcriptional control over EGFR is lost and there is overexpression of EGFR, then The activation will be more than what is required. THis may lead to development of cancer.

2. Mutation of EGFR- If there is a mutation in the EGFR which can make it constitutively active without any ligand binding, then there is always a signal even without ligand. This also may lead to cancer as both of them are hampering cellular homeostasis.