General Oncology Principles Flashcards
What are the three broad classifications of genetic mutations causing cancer?
Tumour Supressor
Proto- Oncogenes
DNA Repair
What are Tumour Supressor Genes?
Both need to be inactivated (recessive)
Can be germ line or acquired
Eg - P53 (involved in cell cycle regulation and maintaining integrity)
What are Proto- Oncogenes?
Functions become enhanced in carcinogenesis
Usually encodes growth factors, growth factor receptors and transcription factors
Only requires one mutation
Eg RAS (encodes GProtein for cellular signal transduction)
What are mutations of DNA repair?
Mutation of these accelerate mutations of tumour supressor and proto-oncogenes
Eg ATM gene (detects DNA damage, produces syndrome of ataxia telangiectasia)
What are BRCA1/2 genes?
Tumour Supressor genes
Carriers have a 55-85% lifetime risk
40% increase of Ovarian with BRCA1
Increased incidence of male breast/prostate/pancreas
What is the RB1 gene?
On chromosome 13 encoding a tumour Supressor gene
If both alleles are inactivated - Retinoblastoma
What is the APC gene?
Tumour Supressor on chromosome 5
Associated with FAP
What is the most important known carcinogen?
Smoking
Responsible for 90% of lung cancers
Synergistic effect on neoplasms caused by other things (eg alcohol)
Name four cancers that alcohol is particularly implicated in
H and N
Oesophageal (particularly squamous)
Breast Cancer
HCC
Diet can have a massive impact on the occurrence of Cancer. Give four cancers particularly related to obesity.
Endometrial
Post Menopausal Breast Cancer
Oesophageal Cancer
Colorectal
How can Colon Cancer risk be reduced with diet?
High levels of vegetable and fibre intake
What is the relation of Salt Fish in terms of cancer?
Increased incidence of Nasopharyngeal Cancer
What is the relation of Aflatoxin (found in corn, nuts, soybeans) and Cancer
Increased incidence of HCC
Viral infections play a significant role in initiating carcinogenesis but do require other factors. Name three carcinogenic viral infections
HPV
Hep B and Hep C
EBV
What two malignancies is EBV most associated with?
Hodgekins Lymphoma
Burkitt’s Lymphoma
Name a carcinogenic bacterial infection
H.Pylori
Strong association with Gastric Adenocarcinoma and a role in the development of gastric lymphoma
Name a carcinogenic parasitic infection
Schistosomiasis
Associated with SCC of the bladder
Name two Radiosensitivity Syndromes
Ataxia Telangiectasia
Blooms Syndrome
Name three industrial exposures and their associated cancers
Napthylamines (Dye/Textile) - Bladder Cancer
Benzenes (Chemical/Rubber) - Haematological
Asbestos - Mesothelioma
Give two examples of potentially carcinogenic pharmacological interventions
Therapeutic cancer treatments (Alkylating)
High dose diethylstilbestriol in pregnancy (causing clear cell carcinoma of female offspring)
Describe three characteristic features of familial cancers
Unusually early age of tumour onset
Multiple/Bilateral Tumours
Familial Clustering (eg breast and ovary, uterus and colon)
Cowden Syndrome is an Autosomal Dominant condition of Hamartomas and increased risk of cancers (breast, thyroid and uterine). Name three symptoms
Mucosal Cobblestone Papules
Acral Keratoses
Craniomegaly
Gorlin Syndrome is a syndrome of increased BCC risk. Give two presenting features
Frontal Bossing
Palmar and Plantar Pits
Neurofibromatoses is a syndrome of increased neural tumours . Give three presenting features
Café au Lait
Cutaneous Neurofibromas
Axillary Freckling
Describe four implications of Familial Genetic Testing
- May be negative but this doesn’t mean there isn’t a risk
- Sometimes might just not have a clear result and will therefore require further testing
- Positive result may cause feelings of guilt in affected family member
- Affected person may discover they’re at risk of other cancers
BRCA1/2 testing if offered if chance of identifying a mutation is >20% . Give three examples of this.
Two breast cancers in under 30y
Three breast cancers in under 40y
Four breast cancers in under 50y
Bowel Cancer screening is done by testing sample for mismatch repair. Give three examples when this is done
One relative under 45y
Two relatives under 55y
Three relatives at any age
How are the results from Bowel Cancer screening managed?
Moderate Risk- Colonoscopy at presentation and 55y
High Risk - 2 yearly colonoscopies from the age of 25
What are the six hallmarks of cancer?
Resisting cell death Sustaining proliferative signalling Evading growth suppressors Ability to invade and metastasise Enabling replicative mortality Inducing angiogenesis
Define Tumour
Abnormal mass of tissue resulting from excessive cell division and evasion of apoptosis
Can be benign or malignant
What is a benign growth?
Not Cancerous
Local problems (do not spread)
Don’t return once removed
What is a malignant growth?
Cancerous
Can spread and invade other tissues
What is Premalignant Dysplasia?
Dysfunctional cell growth and morphological changes in cell nuclei
Lose specific characteristics from tissue of origin
Classified by grade
What is Metaplasia?
Reversible replacement of one cell type by another
Can be benign
What is the difference between stage and grade?
Stage - How advanced the cancer is
Grade - Refers to Histological and pathological features of cells in a neoplasm
There are three main types of biopsy: FNA, Core Biopsy and Surgical Biopsy. What is an FNA?
Negative pressure removes tissue with force
Deep tissue may require radiological guidance
There are three main types of biopsy: FNA, Core Biopsy and Surgical Biopsy. What is an Core Biopsy?
Larger cylindrical core of tissue providing a larger sample
There are three main types of biopsy: FNA, Core Biopsy and Surgical Biopsy. What is an Surgical Biopsy?
Incisional - removes parts of abnormal tissue
Excisional - removes entire area of abnormality (for curative intent)
What are the seven principles of screening?
- The cancer will be a major health problem
- Will be more treatable of detected early
- Should be acceptable to those eligible
- Should be inexpensive
- High sensitivity
- High specificity
- Screening reduces mortality
