Tumour Biomarkers

Question 1

4 uses of tumour markers

Answer 1

Monitoring treatment and detecting recurrence of disease
Diagnosis together with biopsy and imaging
Screening or relatives
Prognosis

Question 2

What makes a good biomarker for cancer screening?

Answer 2

Diagnostic
Sensitive
Specific

Question 3

Predictive value

Answer 3

A measure of how well a test can predict disease

Question 4

What is a suitable test to use in screening men for prostate cancer?

Answer 4

PSA prostate specific antigen

Question 5

3 types of biochemical markers

Answer 5

Protein
Metabolites
Circulating tumour DNA

Question 6

Tumour markers are not ____________ for cancer cells

Answer 6

Specific

Question 7

Tumour marker for colorectal cancer

Answer 7

CEA

Question 8

Tumour marker for ovarian cancer

Answer 8

CA-125

Question 9

Tumour marker for medullary thyroid cancer

Answer 9

Calcitonin

Question 10

CEA in screening

Answer 10

Not useful in screening since only 30% of colorectal cancer patients at time of diagnosis have elevated levels of CEA

Question 11

Non-CRC conditions where CEA is elevated

Answer 11

Breast, lung, haematological cancers

Question 12

CA-125

Answer 12

Glycoprotein attached to cell surface of fallopian tube
Increased in serum when a tumour has increased vasculature
Postoperative CA-125 levels correlate with residual tumour volume
Increased in pregnancy

Question 13

When should CA-125 be measured?

Answer 13

When patients have persistent symptoms

Question 14

Neuro endocrine tumours

Answer 14

Occur in tissue derived from stem cells
APUD cells
Generally slow growing

Question 15

APUD cell

Answer 15

Amine - for high amine content
Precursor Uptake of (amine) precursors
D ecarboxylase - for high content of the enzyme mini decarboxylase (for conversion of precursors to amines)

Have ability to produce neurotransmitters, hormones or paracrine regulators

Question 16

What organ contains neural type cells that can secrete bio active amines or peptide hormones?

Answer 16

Adrenal medulla

Question 17

What organ contains epithelial type cells that can secrete bio active amines or peptide hormones?

Answer 17

Islets of langerhans

Question 18

Symptoms of insulinomas

Answer 18

Headaches
Confusion
Trembling

Question 19

Symptoms of gastrinomas

Answer 19

Bleeding in stomach
Black tar-like stools
Diarrhoea

Question 20

Symptoms of stomatostinomas

Answer 20

Smelly stools
Weight loss
Anaemia

Question 21

Symptoms of glucagonomas

Answer 21

Anaemia
Weight loss
Diabetes

Question 22

Symptoms of VIPomas

Answer 22

Diarrhoea
Weakness
Sickness

Question 23

What are the two distinct categories of GEP-NETs?

Answer 23

Carcinoid - secrete serotonin
Pancreatic endocrine - secrete peptide hormones

Question 24

Name a non GEP-NET

Answer 24

Phaeochromocytoma

Question 25

Phaeochromocytoma

Answer 25

A rare catecholamine-secreting tumour derived from chromaffin cells May be life threatening

Question 26

Medullary cancer of thyroid

Answer 26

Cancer of parafollicular cells which produce calcitonin Characterised by elevated level of calcitonin (also raised in chronic renal failure)

Question 27

MEN

Answer 27

Multiple Endocrine Neoplasia Autosomal dominant inheritance Tumours involving two or more endocrine glands

Question 28

Type 1 MEN

Answer 28

Werners’s syndrome Parathyroid Pituitary

Question 29

Type 2 MEN

Answer 29

Sipple’s syndrome Medullary cancer of thyroid Phaeochromocytoma

Question 30

Diagnosis of NET

Answer 30

Clinical presentation Peptide screen CgA Urinary 5HIAA & 5HT CAT MRIPET Octreotide scitigraphy MIBG Biopsy

Question 31

General NET markers

Answer 31

Chromogranin A

Question 32

Specific marker of NET

Answer 32

E.g. gastric if a gastrinoma E.g. measure urinary plasma catecholamines for phaeochromocytoma

Question 33

5-HIAA

Answer 33

Serotonin metabolite Biochemical test for carcinoid (NET)

Question 34

Biochemical test for Phaeochromocytoma

Answer 34

24hour secretion of catecholamines

Question 35

What is clonidine?

Answer 35

Alpha-adrenergic receptor agonist. Gaslights brain into thinking catecholamine levels are higher than they really are Clonidine causes the brain to reduce its signals to the adrenal medulla => lowering catecholamine release => lowers plasma levels = negative feedback Doesn’t happen if there is a tumour secreting catecholamines