Cancer

Question 1

what is cancer

Answer 1

Uncontrolled cell division which results in a tumour.

Question 2

Why are not all tumours cancerous

Answer 2

Benign- non cancerous so dont spread
Malignant- Spread throughout the body via metastasis so they are cancerous

Question 3

Characteristics of a Benign tumour

Answer 3

Grow slowly
Well differentiated
Normal nuclei
Well defined borders; cell adhesion molecules stick cells together so they are often surrounded by a capsule so remain within the tissues.
Easy to treat- can be removed by surgery

Question 4

Characteristics of Malignant tumour

Answer 4

Grow rapidly
Poorly differentiated
Larger nuclei
Poorly defined borders and not encapsulated so can break off and spread to other tissues (metastasis)
Removed by radiotherapy/ chemotherapy but is more likely to recur

Question 5

Function of tumour suppressor

Answer 5

Code for a protein involved in control of cell division
In particular, stopping cell cycle
Also involved in causing apoptosis

Question 6

How does mutation in tumour suppressor gene result in the formation of tumours

Answer 6

Mutation alters the amino acid sequence and tertiary structure of protein to create a non functional protein.
Or increased methylation prevents transcription so as a result damaged DNA is not repaired so uncontrolled cell division

Note: Need 2 mutated alleles

Question 7

Proto-oncogene function

Answer 7

codes for a protein involved in control of cell division in particular stimulating cell division

Question 8

Role of Oncogene in development of tumours

Answer 8

Mutation could turn it into permanently activated oncogene. Decreased methylation/ increased acetylation causes excess transcription

Note: only need 1 mutated allele

Question 9

Role of increased oestrogen conc in development of breast cancer

Answer 9

High oestrogen conc such as adipose tissues in breasts, cell division uncontrolled
Growth of cancer minimised with drugs blocking production e.g. Tomoxifen prevents oestrogen binding to receptor