7) Biomarkers Flashcards Preview

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Flashcards in 7) Biomarkers Deck (29)
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1
Q

What is a cancer biomarker?

A

A substance or process that is indicative of the presence of cancer in the body

2
Q

What are the uses of cancer biomarkers?

A

Diagnosis, prognosis, predictive (how well a patient will respond to treatment

3
Q

What are some different types of biomarkers? (broad)

A

Genetic - DNA mutations, mRNA expression
Epigenetic - DNA methylation
Proteomic - protein levels
Glycomic - glucose metabolism

4
Q

What molecular markers can be obtained from tissues of the body?

A

DNA, RNA, protein, miRNA and mRNA

5
Q

What are some sources of biomarkers?

A

Blood, tissue, urine, semen

6
Q

What are features of the ideal biomarker?

A

Specific, sensitive (detection at early stage), predictive, robust, minimally invasive, reflect kinetics (e.g. tumour size increases, biomarker level increases)

7
Q

Give examples of genetic biomarkers for risk:

A

Mutation in EGFR
BRCA1/2
Abnormal methylation of tumour suppressor genes

8
Q

How can prostate specific antigen be used as a biomarker?

A

It is elevated in some patients with prostate cancer so can be used for detection
Combined with grade and stage for risk stratification

9
Q

How is HPV used as a biomarker?

A

Pap smear for HPV detection and HPV used a risk predictor

10
Q

What is a diagnostic biomarker in liver cancer?

A

Alpha-fetoprotein

11
Q

What is a diagnostic biomarker in ovarian cancer?

A

Cancer antigen 125

12
Q

What is a diagnostic biomarker in colorectal cancer?

A

Carbohydrate antigen 19-9

13
Q

What is a diagnostic biomarker in pancreatic cancer?

A

Carcinoembryonic antigen (CEA)

14
Q

What is a biomarker in metastatic breast cancer?

A

CA15-3, tracks progress

15
Q

Give an example of genetic diagnostic biomarker of cancer:

A

BCR-ABL translocation (Philadelphia chromosome) in CML

16
Q

What is a prognostic biomarker?

A

Indicates the likely course of the disease in an untreated individual

17
Q

What is a predictive biomarker?

A

Identifies subpopulations of patients who are most likely to respond to a given therapy

18
Q

Give examples of prognostic biomarkers:

A

TIMP1 in multiple myeloma

Oestrogen receptor in breast cancer

19
Q

Why are predictive biomarkers needed?

A

Reduces the unnecessary treatment and adverse effects

Can quickly highlight acquired resistance to therapy

20
Q

Give examples of predictive biomarkers:

A

HER2 amplicfication, targeted by trastuzumab
EGFR mutation, response to erlotinib in non-small cell lung cancer
BRAF mutation, response to vemurafenib in metastatic melanoma

21
Q

What is tumour heterogeneity?

A

Different regions in the tumour show different mutations

22
Q

Why are liquid biopsies advantageous?

A

Give a more representative sample of all the clones in the tumour and is minimally invasive

23
Q

What are some examples of biomarkers from liquid biopsy?

A

Circulating tumour cells
Cell free DNA
Exosomes - tiny vesicles shed form cells, giving info about DNA

24
Q

What is cell free DNA?

A

Derived from apoptosis, necrosis or active secretion and elevated in tumour cell turnover. Shows mutations, copy number variants and methylation

25
Q

How can cfDNA act as a diagnostic biomarker?

A

Can show mutations that the tumour has gained, also helps with prognosis

26
Q

How can cfDNA act as a predictive biomarker?

A

Shows mutations that the tumour has causing resistance to therapy
Also shows gene amplified that can cause relapse

27
Q

What are circulating tumour cells?

A

CTCs shed into bloodstream (rare), can be prognostic and predictive and used in monitoring

28
Q

How can circulating tumour cells be used as biomarkers?

A

Isolated and sequenced, tested and cultured to give information about mutations used for prognosis and predictions

29
Q

How can circulating miRNAs be used as biomarkers?

A

Regulate gene expression so can be used in diagnosis, prognosis and predictive