Tumour Pathology 5 Flashcards
<p>What is carcinogenesis due to?</p>
<p>Geographic and environment factors</p>
<p>Age</p>
<p>Heredity</p>
<p>What are the 2 categories of normal genes that can be disrupted and cause cancer?</p>
<p>Tumour suppressor genes (anti-oncogenes)</p>
<p>Proto-oncogenes</p>
<p>What are tumour suppressor genes?</p>
<p>Normal growth inhibitor genes that regulate:</p>
<p></p>
<p>Mitosis (Rb)</p>
<p>Apoptosis (p53)</p>
<p>DNA repair</p>
<p>What are anti-oncogenes also known as?</p>
<p>Tumour suppressor genes</p>
<p>What does p53 regulate?</p>
<p>Apoptosis</p>
<p>What is a key event in tumour formation?</p>
<p>Uncontrolled proliferation, due to cell cycle dysfunction, due to loss of tumour suppressor gene function</p>
<p>What are other mutations that can directly impact the performance of pRb?</p>
<p>CKD4</p>
<p>Cyclin D</p>
<p>CDKIs</p>
<p>What does absent or inactive pRb do?</p>
<p>Releases the brake on the cell cycle, causing cell proliferation</p>
<p>What are the causes of retinoblastomas?</p>
<p>Sporadic</p>
<p>Inherited</p>
<p>What are examples of inherited predispositions to cancer?</p>
<p>Familial retinoblastoma</p>
<p>Familial adenomatous polyposis of colon</p>
<p>Multiple endocrine neoplasia</p>
<p>Neurofibromatosis</p>
<p>Van Hippel-Lindou Syndrome</p>
<p>What are some known inherited mutations of anti-oncogenes?</p>
<p>APC</p>
<p>p53</p>
<p>Rb</p>
<p>p16</p>
<p>BRCA1/2</p>
<p>What does an inherited mutation of APC cause?</p>
<p>FAP colon cancer</p>
<p>What does an inherited mutation of Rbcause?</p>
<p>Retinoblastoma</p>
<p>What does an inherited mutation of p16 cause?</p>
<p>Malignant melanoma</p>
<p>What does an inherited mutation of BRCA1/2 cause?</p>
<p>Breast cancer</p>
<p>What is the function of APC?</p>
<p>Signal transduction</p>
<p>What is the function of p16?</p>
<p>Cell cycle/apoptosis after DNA damage</p>
<p>What is the function of Rb?</p>
<p>Cell cycle regulation</p>
<p>What is the function of p16?</p>
<p>Inhibits CDKs</p>
<p>What is the function of BRCA1/2?</p>
<p>DNA repair</p>
<p>What are proto-oncogenes?</p>
<p>Normal genes coding for normal proteins that regulate growth</p>
<p>What are some functions of proto-oncogenes?</p>
<p>Growth factors</p>
<p>Growth factor receptors</p>
<p>Signal transduction</p>
<p>What are oncogenes derived from?</p>
<p>Proto-oncogenes</p>
<p>What are oncogenes activated by?</p>
<p>Alteration of proto-oncogene structure</p>
<p>Dysregulation of proto-oncogene expression</p>
What can cause an alteration of proto-oncogene structure?
Point mutation
Chromosome rearrangements and translocation
What do oncogenes generate?
Active oncogene products
What are active oncogene products?
Growth factors
Growth factor receptors
Proteins involved in signal transduction
Nuclear regulatory proteins
Cell cycle regulators
How many copies of an oncogene do you need to cause cause?
Only one, not two
What is the process of viral carcinogenesis?
1) Virus inserts genome near a host proto-oncogene
2) Viral promoter or other transcription regulation element cause proto-oncogene overexpression
What is the relationship between reteroviruses and carcinogenesis?
Reteroviruses insert an oncogene into host DNA causing cell division
What are some viruses that are known to cause cancer?
HPV
Hepatisis B
EBV
What cancer does HPV cause?
Cervical cancer
What cancer does Hepatitis B cause?
Liver
What cancer does EBV cause?
Burkitt lymphoma
What is the process of chemical carcinogenesis?
1) Chemicals react with DNA to form covalently binded products known as DNA adducts
2) Leads to activation of oncogenes and suppression of tumour suppressor genes
What is formed when chemicals bind to DNA in chemical carcinogenesis?
DNA adducts
How many steps are necessary for carcinogenesis?
More than one step, a series of mutations is required
How does the number of mutations change as time goes on?
Mutations accumulate
