Intro to Cancer

Question 1

what are the common types of cancer for each gender?

Answer 1

male - prostate/lung/bowel/other
female - breast/lung/bowel/other

Question 2

what type of cells produce cancerous cells?

Answer 2

• Carcinomas (80%)
  – derived from epithelial cells eg lung, colon, prostate
• Sarcoma (1%)
  – derived from (non-epithelial) mesenchymal cells, eg osteosarcoma, liposarcoma
• Haematological malignancies (17%)
  – Lymphoma and leukemia

Question 3

whats the difference between benign and malignant?

Answer 3

benign
- local growth
- no invasion of surrounding tissue

malignant
- invasion of neighbouring tissue
- potential to metastasis

Question 4

what are majority of cancer deaths caused by?

Answer 4

90% cancer deaths caused by metastasis

Question 5

what is the characteristics of cancerous cells?

Answer 5

• Immortalization
• Loss of contact inhibition
• High saturation density
• Reduced requirement for mitogenic growth factors
• Inability to halt proliferation in response to deprivation of growth factors
• Altered morphology
• Anchorage independent
• Tumorigenicity

Question 6

what is a proto-oncogene?

Answer 6

a proto-oncogene is a normal gene that can become an oncogene due to mutations or increased expression. The product of an oncogene is tumour inducing agent

Proto-oncogenes are typically:
- Proteins involved in promoting entry into the cell cycle (eg Receptor tyrosine kinases, Ras)
- Proteins that protect cells from apoptosis (Bcl2)

Question 7

what are tumour suppressor genes?

Answer 7

Tumour suppressor genes are anti-growth genes that are inactivated in cancer cells, both copies require inactivation for the growth control to be lost

Question 8

what can inheritance of mutant forms of tumour suppressor gene APC cause?

Answer 8

prone to thousands of polyps = polyps progress to cancerous polyps = metastasis

Question 9

how can genetics affect cancer progression?

Answer 9

APC is generally the first tumour suppressor to be lost, the order of subsequent changes is variable
* Loss of tumour suppressors is more common than oncogene activation
* There are also likely to be many epigenetic changes which can alter gene expression, eg promoter methylation

Question 10

what are the main causes of cancer?

Answer 10

1. genetic predisposition - family history
2. lifestyle - smoking/age/alochol/exercise/diet/food - high red meat intake and processed foods
3. environmental causes - UV radiation/albestos
4. micro-organisms - H.Pylori- stomach cancer/HIV-kaposi sarcoma

Question 11

how is breast/colon/thyroid cancer mainly caused?

Answer 11

breast - BRCA1/BRCA2/p53 tumour suppressor
colon - APC tumour suppressor
thyroid - RET oncogene

Question 12

what are the current screening programs in the uk?

Answer 12

mammograms for breast cancer (>50years old, women)
cervical smear tears (women)
bowel cancer (>74years, men and women)

Question 13

what are the main types of cancer treatment?

Answer 13

surgery to remove tumour
chemotherapy
radiotherapy
oncoproteins
angiogenesis inhibitors
immune therapy
alkalying agents

Question 14

what is neoadjuvant therapy?

Answer 14

reduce tumour size before surgery

Question 15

what is adjuvant therapy?

Answer 15

therapy to reduce cancer recurrence after surgery