benign vs malignant

Question 1

How does cancer develop ?

Answer 1

Carcinogen induced mutation 
Mutation affects genomic integrity 
Addition driver mutations 
Emergence of sub clones
Heterpgenous cancer

Question 2

What is a passenger mutation

Answer 2

Genetic changes in tumours with no consequences

Question 3

Driver mutations

Answer 3

In addition to initiator mutation and cause development of cancer

Question 4

Genetic mutation in colorectal cancer

Answer 4

APC

Question 5

How does colorectal cancer develop ?

Answer 5

Stem cells divide

As they move up crypts,

Question 6

APC forming colorectal cancer

Answer 6

• Wnt signalling pathway
• No Wnt ligands means no binding to Fz receptor and signalling from this receptor doesn’t occur
• APC/Axin/CKI complex formed which egrades B-catenin
• Wnd ligand binds to Fz receptor and complex recruits Axin
• B catenin released from this complex and will not be degraded
• B catenin moves to nucleus and alters gene expression
• Wnd expression = anti-apoptosis processes
• No APC means Wnd expressed at base of crypt because B catenin not degraded
• In villi, no APC means Wnd abnormally expressed = proliferation

Question 7

KRAS mutation

Answer 7

• RAS at plasma membrane
• Ligand binds to receptor = signal transduced downstream
• Conversion to GTP activates RAS
• RAs signals through pathways = proliferation
• KRAS is proto-oncogene

Question 8

Cells present in tumour microenvironment

Answer 8

• Fibroblasts
• Myofibroblasts
• Endothelial cells
• Pericytes
• Adipose cells
• Inflammatory cells
• Secreted soluble factors and ECM