Neoplasm V Flashcards
What does a translocation of the BCL-2 genes from chromosome 14to 18 do?
Causes an overexpression of BCL-2 leading to prevention of B-lymphocyte apoptosis.
This ultimately leads to follicular lymphoma.
What happens if the APC gene is over expressed?
Prevents nuclear transcription leading to colorectal cancer.
What is the p53 gene responsible for and what cancer is it associated with?
Normally transcribes p21 (blocks g->S phase)
Li Fraumeni syndrome.
What is the Rb gene responsible for and what cancer is it associated with?
Tumor supressor gene that normally inhibits E2F (Blocks G to S phase)
Retinoblastoma, osteosarcoma, and soft tissue sarcoma.
What is the VHL gene responsible for and what cancer is it associated with?
Inhibits HIF1a and leads to Von Hippel-Lindau syndrome.
The APC gene and B-catenin are components of what pathway?
WNT signalling pathway controlling cell fate, and cell polarity during embryonic development.
Also controls tisue proliferation in the adult bone marrow, skin, and intestine.
What is the WNT pathway in control of?
Tissue proliferation, adult bone marrow, skin and intestine.
How does P53 work?
P53 activates BAX leading to apoptosis in the event that the damaged cell is not fixed.
It activates P21 leading to G1 arrest
P51 also activates GADD45 which is a DNA repair mechanism.
How does HPV E6 and HPV E7 effect the cell cycle?
E6 down regulates p53 leading to lack of BAX production.
E7 inactivates p21 leading to lack of cell cycle arrest.
It also inactivates RB leading to lack of cell cycle arrest.
What cancer is related to the Rb gene?
Retinoblastoma
Osteosarcoma
Soft tissue Sarcoma
What is Knudson’s two hit hypothesis?
Both alleles of Rb locus must be inactivated thus, two hits are required!
Typically the first hit is through the germ line inheritance, the second can be a random mutation.
What is the VHL gene for?
Where is it found?
Tumor suppresor gene located on chromosome 3p and is part of the ubiquitin ligase complex.
Regulates nuclear transcription via HIF-1a
What disease is caused by a VHL gene mutation?
VHL syndrome leading to: Hereditary renal cell carcinomas Pheochromocytomas Hemangioblastomas of CNS Retinal angiomas Renal cysts
What is the Warburg effect?
Cancer cells have an affinity for glucose and convert it to lactos via the glycolytic pathway.
What is a PET scan?
Pt injected with 18F-fluorodeoxyglucose that only cancerous cells can take up, allows for visualization of the tumor.
What are epigenetic changes?
Methylation of gens resulting in a change in expression without mutation.
What is P-glycoprotein?
MDR1 Multidrug resistant protein, serves as a tool for tumor cells to evade chemotherapy.
What are lamellated calcified spherule Psammoma bodies most commonly seen in?
Concentric lamellated calcified spherules seen in:
Papillary thyroid carcinoma
What are chemical carcinogens and how do they act?
Highly reactive electrophiles that steal electrons causing cell damage.
Are:
Direct acting: Act without modificaton
Indirect acting: Require metabolic activation.
Give some examples of direct acting carcinogens
Chlorambucil
Busulfan
Melphalan
Give some examples of Indirect caricinogens
Polycyclic aromatic hydrocarbons found in cigaret smoke.
Effect the liver!
Where does B-Naphthylamine effect?
Causes bladder cancer and is heavily exposed in workers that deal with aniline dye and rubber industries.
What is Alfatoxin B1?
IS a fungus mycotoxin causing hepatocellular carcinoma due to p53 mutations.
What is Nitrosamines?
Causes Gastric cancer from reaction of nitrostable amines and nitrite in the stomach.
Nitrite is produced from nitrate and used as a preservative.
What sort of cancer promotion does Estrogen cause?
Promotes liver tumors.
What sort of cancer promotion does Diethyl-stilbesterol cause?
Post menopausal endometrial cancer, vaginal cancer in offspring exposed in utero.
What sort of cancer is caused by high dietary fat?
High fat causes increased bile leading to colon cancer.
