L18 - Cancer Signalling

Question 1

A large % of patients have over-expession of ____, which is generally associated with poor outcome

Answer 1

EGFR

overexpressed in nearly all cancer cells

Question 2

ON EXAM

What are the results of enhanced EGFR signalling?

Answer 2

Proliferation - increase expression of proteins involved in cell cycle progression and decreases expression of cell cycle checkpoint proteins

Survival and resistance to therapy - increased anti-apoptotic protein expression

Angiogenesis - increase pro-angiogenic proteins

invasion/metastasis - increased expression of proteins involved in ECM degradation

Question 3

What are the mechanisms of enhancing EGFR signalling used by Cancer cells?

Answer 3

1. EGFR over-expression - more copies of the receptor
2. EGFR Mutation
3. Increase autocrine signalling through increase ligand expression - more EGF being released and binding to the receptor
4. Enhanced downstream signalling by mutation
5. Reduced or loss of phosphatase expression