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Flashcards in Molecular Biology of Cancer Deck (42):
1

What is Neoplasia?

Tumour growth

2

What is Neoplasm ?

Tumour

3

What is adenocarcinoma

a malignant tumour of glandular epithelium

4

What is adenoma ?

-a solid, benign glandular tumour

5

What is anaplasia?

loss of differentiated charachteristics

6

What is aneuploidy?

presence of extra chromosome

7

What is angiogenesis?

new growth of blood vessels

8

What is a benign tumour?

-a tumour that does not invade or metastasize

9

What is a carcinoma ?

- malignant tumour of epithelium

10

What is hyperplasia?

increase in number of cells in response to stimulus

11

What is Leukemia ?

-malignant disease of blood forming organs leading to over production of neoplastic white blood cells

12

What is lymphoma ?

- solid tumour of T or B lymphocytes e.g. in lymph nodes, thymus or spleen

13

What is a malignant tumour?

-tumour that is capable of invading surrounding tissues and of metastasizing

14

What is metaplasia?

-abnormal alternation in the structure of cells

15

What is metastasis?

-a secondary tumour arising from cells carried to a distant site from a primary tumour

16

What is a myeloma ?

a plasma cell tumour

17

What is an oncogene?

-a gene causing cancer

18

What is a proto-oncogene?

-the normal cellular counterpart of an oncogene

19

What is a sarcoma?

a malignant tumor of mesenchyme (connective tissue)

20

What is a transformation?

-in the context of cancer means a change of morphological appearance of a cell

21

What is a tumour suppressor gene?

-genes whose normal role is to regulate cell division in a negative fashion ( leading to cell growth arrest) and following mutation or loss of one or both alleles , may have the effect of allowing cells to progress through cell division in an unrestricted fashion.

22

What is Cancer?

Uncontrolled cell Division and Uncontrolled cell Survival

- in cancer cells there is loss of control of both the division /differentiation process and apoptosis.

23

What statistics do you know about cancer?

- 1 in 3 people will suffer from cancer in their life
- 1 in 4 deaths due to cancer
- 6 million new cases every year worldwide.

24

How many forms of cancer are there?

- more than 200 different forms of cancer
- they differ according to the cell type from which they derive.
- 85% are epithelial origin called carcinomas
- these cells form the barrier layer exposed to 'carcinogens' in the environment
- skin cancers are ' basal cell carcinoma ' ,
- lung cancers are ' adenocarcinoma '
- colon cancers are ' colorectus carcinoma'

25

Other origins of cancer cells?

-1% - from connective tissue
(sarcomas )
- 8% - from haemapoetic cells
(lymphomas, leukaemias )

26

different cancer types have very different prognosis? ( give examples)

e.g.
cancer of the lip -99% survival
cancer of lung - 8% survival

27

Factors that control survival time?

-early diagnosis
- lack of spread to other sites
- response to treatment
- quality of care

28

What is the Molecular basis of cancer?

- mutations in the DNA that codes for genes whose products are normally involved in the control of division, differentiation and cell survival
- most mutations are somatic !
- some are inherited !
- this has lead to great insights into normal growth and development

29

Why is it said that cancer is a multistep process?

- because many unlikely mutations must accumulate in one cell
- mutations that affect genetic stability are of especial importance
-these mutations allow new variants to arise more quickly
- cancer cells are genetically unstable
which allows rapid evolution - therefore allowing drug resistance

30

What are the stages in tumour development?

1. mild dysplasia (25-30 divisions)
2. severe dysplasia (100 million cells visible on xray)
3. carcinoma in situ (1000 million cells tumour is palpable )
4. invasive carcinoma - (tumour breaks through basement membrane )
5. malignant metastasis ( 1,000,000 million cels tumour throughout body and organs - death!)

31

What are some charachteristics of tumours?

-avoiding immune response
-tumour promoting inflammation
-deregulating cellular energetics
-genome instability and mutation

- the tumour microenvironment is very different from normal tissues.

- the tumour cells have adapted a glycotic metabolism

32

What is the genetic basis of human cancer?

-activation of genes by mutation that promote cell proliferation and cell survival
- dominant gain of function mutations
- protooncogene mutates to oncogene

- regulated growth signal /survival signal ==== mutation === unregulated growth signal / survival signal
- inactivation of genes by mutation that normally limit cell proliferation and cell survival
-recessive loss of function mutations
- tumour supresser gene ==== mutations ==== mutant tumour supressor gene

33

What do we know about tumour supressor genes?

- because loss of function mutation need to lose both parental copies for affect to be seen
- if you inherit a germ line mutation in one you are at a greater risk of developing cancer.

34

What are some examples of tumour suppressor genes?

- p53 gene - mutant in more than 50% of human cancerss
- part of cells checkpoint repsonse to DNA damage

- retinoblastaoma gene - mutant in all retinoblastomas but also lung and other cancers.
- key negative regulator of the transcription of genes needed for cell cycle.

-adenomatous polypossis coli gene (APC) mutant in most colorectal cancers at early stage in disease. involved in chromosome stability

HmutS gene - mutant in some forms of colorectal cancer - mutations cause a defect in DNA mismatch repair

35

What is the relationship between mutations and cancer?

- since somativ mutation of DNA underlies cancer development it is thought that:

1. mutagens are carcinogens
2. cancer is avoidable if mutagen exposure can be reduced.
3. mutagen testing can help identify cancer causing agents in the environment.

36

Give some examples of oncogenes?

- mutant growth factor receptors
- single cascade components
- transcription factors
- cell-cell components
- anti- apoptotic factors

37

What are chromosomal translocations?

it is found that in cancer there is chromosomal instability
- tumours are aneuploid ( incorrect number - triploid, haploid )
- tumours have many brokem and rearranged chromosomes clearly seen using FISH and CGH techniques
= careful cytology on leukaemias showed certain common very conserved events.

38

What is Gene Amplication?

- cytological examination of tumours shows double minute chromosomes
- cytological examination of tumours shows HSRs homogenously staining regions
- both contain multiple copies of same Chromosomal fragment.

39

What is gene sequencing?

- Human genome sequence ' complete'
- cancer genome sequencing project
- use of next generation sequencing
- exosome sequencing

40

What is hypoxia's role in tumour development?

- the tumour cells are often exposed to low oxygen, hypoxia or inflammation

41

What are cancer cell migration steps ( 5 steps !)?

1. escape from the tumour
2. invasion of vascular system
3. movement through the blood stream
4. homing to distant organs
5. attachment
6. invasion

42

What is cancer therapy ?

- understand the genetic defect
- find the achillies heel of the cancer
- block new blood vessel formation
- change the microenvironment
- target on mutant cells
- personalised cancer treatment.