Cancer

Question 1

Cancer

Answer 1

Term for disease :

Uncontrolled proliferation
INVASION of nearby tissues
SPREAD via the blood/lymph

Question 2

Tumour

Answer 2

abnormal mass of tissue that results when cells divide more than they should or do not die when they should

Immortality
Uncontrolled proliferation

Question 3

Carcinogenesis

Answer 3

Multi-stage process - involving multiple hits

Initiation : interaction carcinogen with DNA

Promotion : Selective growth advantage, early PRE CANCER : ADENOMA - reversible

Progression: enhanced cell division (increased mutation) - later PRE CANCER - late adenoma (reversible)

Malignant conversion : Cancer - irreversible

Question 4

What is the role of driver mutations
What is the role of passenger mutations

Answer 4

Driver mutations - result in increased growth and increased survival
2-8 required for carcinogenesis

Passenger mutations - always happening behind the scene - associated with loss of function of key DNA repair genes

Question 5

What is the modern view of cancer

What does this mean for treatment?

Answer 5

There is hetereogeneity within the tumour - different cells respond to different drivers e.g. hormones, cytotoxic drugs etc.

TUMOUR MICRO-ENVIRONMENT

means you have the ability for targeted therapies but also that cancer is complex

Question 6

What are the stages that show that cancer is a disease of the genome?

Answer 6

Epigenetic/genomic alterations (mutation - loss/gain of function)

leads to altered protein product (mutant form/overexpression)

leads to altered pathways (activated cell survival - loss of apoptotic signals) - altered cell cycle regulation

Altered biology : uncontrolled proliferation, angiogenesis and tissue invasion

Question 7

4 types of carcinogen

Answer 7

Chemical
physical
Viral
hereditary cancer predisposition syndromes

Question 8

Example of chemical carcinogen :

Direct - alkylating agent
Indirect - benzene

Answer 8

Direct carcinogen : Alkylating agent - directly damages DNA - introduces alkyl groups into DNA disrupting structure and function

Indirect Carcinogen: PROCARCINOGEN : become carcinogenic after activation in body :

Benzopyrene- component of tobacco smoke and charred food - forms adducts with purine bases of DNA

Question 9

Example of chemical carcinogen : cisplatin

Answer 9

platinum agents - chemotherapies - cisplatin/carboplatin

Irreversibly bind at guanines of the DNA - crosslink the two DNA strands - inhibiting strand seperation and preventing DNA replication

Question 10

examples of physical carcinogens
ionising radiation

Answer 10

ionising radiation

xray/gamma ray: : low linear energy transfer

particulate radiation: protons/neutrons/electrons - high linear energy transfer

Question 11

example of physical carcinogen
non-ionising radiation

Answer 11

UV light - solar UV exposure
leads to squamous cell carcinoma
basal cell carcinoma
cutaenous malignant melanoma