13. Tumour Markers, Cell Cycle, Carcinogenesis Flashcards
Why is carcinogenesis associated with old age?
Enough time to be exposed to many carcinogens
The elderly are also mildly immunosuppressed
Why do some cancers occur in childhood?
Due to inherited mutations
What are tumour markers?
Antigens made by or on the surface of the tumour
Why are tumour markers clinically useful?
Diagnosis
Follow up
Screening
What tumours produce CEA?
Colon
Stomach
Pancreas
What tumour marker is made by a choriocarcinoma?
hCG
What tumour marker is produced by a hepatocellular carcinoma or yolk sac tumour?
AFP
What tumour marker is produced in a prostatic carcinoma?
PSA
What samples can tumour markers be found in?
Blood
Urine
Tissue section
What immunohistochemical stain is used to show a carcinoma?
Cytokeratin
What immunohistochemical stain is used to show a sarcoma?
Vimentin
What immunohistochemical stain is used to show a lymphoma?
CD45
What immunohistochemical stains are used to show a melanoma?
S100P
Melan A
What immunohistochemical stain is used to show a thyroid tumour?
Thyroglobulin
What proteins control the cell cycle?
Oncoproteins
Tumour suppressor proteins
What is hyperplasia?
Increased cell proliferation due to a controlled response to a stimulus
Stops when the stimulus is withdrawn
Give the stages of the cell cycle
G0 G1 S G2 M
What is metaplasia?
1 adult epithelium changes to another type
Normally protective but can have malignant potential
Give an example of metaplasia
Barrett’s oesophagus
Which gene is altered in familial breast cancer?
BRAC 1 or 2
What is the normal role of proto-oncogenes?
Regulate normal cell proliferation
What is another name for an active proto-oncogene?
Cellular proto-oncogene
What processes can cause proto-oncogenes to be upregulated?
Point mutation Amplification Translocation Insertion of viral DNA Methylation (environmental)
How does the Epstein-Barr virus cause Burkitt’s lymphoma?
Causes a translocation which activates c-myc proto-oncogene
What is the normal role of tumour suppressor gene?
Suppress cell proliferation
How can tumour suppressor genes be inactivated?
Deletion
Mutation
Translocation
Name 2 tumour suppressor genes
APC (lost in familial colon cancer)
P53
What is the function of repair genes?
Repair DNA defects
What is the role of anti-apoptotic genes in carcinogenesis?
Give a survival advantage to tumour cells
Name an anti-apoptotic gene
BCL2
How do tumour cells evade immune detection?
Tolerance
Local suppression of immune cells
Dysfunction in T cell signalling
What receptor on lymphocytes allows tumour cells to suppress them?
PD1
What are the classes of carcinogens?
Chemicals Radiation Hormones Viruses Chronic inflammation Parasites
