Cancer Flashcards
What is the #2 cause of death in the U.S. behind cardiovascular disease?
Cancer
What are the general causes of cancer?
Lifestyle, environmental pollutants, genetics, impaired immune surveillance
What is a major exception to the idea that once we are full grown that most cell proliferation ceases?
Skin cells and cells that line mucous membranes must be continually replaced due to wear and tear (must be carefully controlled)
What are the two basic types of control systems that can be disrupted when cancer develops?
1 systems that promote normal cell growth
2 safeguard systems that protect against uncontrolled cell growth
What is a proto-oncogene?
A particular gene that WHEN mutated can cause a cell to proliferate inappropriately
What is an oncogene?
MUTATED version of gene that has the potential to cause cancer
A mutation of which tumor suppressor protein is found commonly in most tumors?
p53
What normally occurs to cells if genetic damage due to mutation is severe?
Apoptosis
p53 is coded for by what tumor suppressor gene?
TP53 (anti-oncogene)
What usually happens to mice that lack p53?
Die of cancer within 6-7 months
What is the current estimation for how many mutations are required to produce most common cancers?
4-7
Why does cancer usually occur later in life?
Takes a relatively long time to accumulate multiple mutations (4-7, on average) to cause cancer
What types of cancers are more common in humans with weakened immune systems?
Lymphoma and virus-associated cancers
Karposi sarcomas are associated with which virus and condition?
HHV-8 and AIDS
What type of cancer is associated with HPV?
Cervical
What type of cancer is associated with hepatitis B (20%)?
Liver
It is estimated that what percentage of cancers are caused by viruses?
15-20%
What did most humans die of 200 years ago?
Infectious disease
Mice deficient in what protein were more likely to develop tumors (primarily in the intestine) even while being raised in patogen free conditions?
RAG-2 protein
What is the function of RAG-2 protein?
Necessary to assemble BRC and TCR
In humans with cancer, higher counts of what kind of cell associated with the tumor are linked to longer survival rates?
Lymphocytes (B and T cells)
CTLs are effective against what kind of cancers?
Cancerous blood cells
Why aren’t CTLs effective against virus-associated tumors?
Due to hiding viruses which CTLs aren’t effective against
Why aren’t CTLs effective against spontaneous tumors?
Traffic pattern issues
Conflict between self tolerance and surveillance
Unable to supply co-stimulation
What kind of tumors make up the majority of cancers?
Spontaneous
Why are CTLs effective against cancerous blood cells?
Traffic patterns of cancer cells in blood intersect with virgin T cells
Some cancerous blood cells express high levels of B7 (co-stimulation)
Which are quick acting against cancer: macrophages or CTLs?
Macrophages
How can hyperactivated macrophages kill certain types of cancers?
Release of TNF, preventing angiogenesis leading to tumor necrosis
What benefit allows macrophages to intercept at an early stage?
Macrophages are typically located in tissues where most tumors occur
What effect does abnormal expression of surface molecules on tumors have on macrophages?
Enables them to differentiate between cancer cells and normal cells
How can natural killer cells affect cancer cells?
In vitro NK cells can destroy some cancer cells
NK cells target cells expressing low MHC I levels and unusual surface molecules
Quick acting
On call in blood (like neutrophils)
What vaccines are used to prevent certain cancers?
Hepatitis B (preventing liver cancer) HPV (preventing cervical cancer)
What types of HPV are implicated in 70% of all cervical cancer?
HPV-16 and HPV-18
Which types of HPV are associated with genital warts?
HPV-6 and HPV-11
Which HPV vaccine is directed against HPV-16, 18, 6, and 11?
Merck vaccine
Which HPV vaccine is directed against HPV-16 and HPV-18/
GSK
HPV vaccines are made from what?
Viral coat proteins
What manufactured antibody enables T cells to more effectively attack cancer cells?
MPDL320A
What protein does MPDL320A target?
PD-L1 (programmed death-ligand 1)
Where is PD-L1 found, and what is its function?
On surface of many cancer cells; impairs the immune system’s ability to fight the disease
What substance can be injected into a tumor to hyperactivate the macrophages to destroy the tumor?
Bacille Calmette-Guerin (BCG)
The BCG vaccine is sometimes used to immunize (not always effectively) against what disease?
TB
Overall, what two types of cells can provide surveillance against certain types of cancer cells?
NK cells and macrophages
Why is a functioning immune system important in fighting cancer?
May reduce the frequency of metastasis or slow metastatic process once primary tumor has formed
