Chapter 12: Cancer Flashcards
What are the ABCs of skin cancer?
Asymmetry - when half of the mole doesn’t match the other half
Border - when the border of the mole is ragged or irregular
Color - when the color of the mole varies throughout
Diameter - if the moles diameter is larger than a pencils eraser
Can dark-skinned people get skin cancer?
Yes. More melanin but still can get skin cancer
What do most strains of HPV cause?
Warts on the body and the body can clear the infection on its own
What is the spread of cancer cells?
Metastasis
What is cancer?
A malignant tumor
What is a thymine dimer?
When T attaches to A next to it instead of across. Result of a tan
What does inheriting one bad copy of BRCA 1 or having a mutation of BRCA 1 cause?
Increased risk for breast cancer bc there is no room for error with the other copy. 60% chance of developing before 50 compared to 2% if both were normal
What have Henrietta Lacks’ cells been used for?
Polio vaccine, cancer, AIDS, gravity, radiation, 11,000 patents, 60,000 papers, and 20 tons of her cells have been used
The 2nd most commonly diagnosed cancer in women
Breast cancer
What leads to mutations of the cells own DNA?
Errors during replication and mitosis and carcinogens
What is Li Fraumeni syndrome?
Inherited mutation of the p53 gene. 50% of people with it develop cancer by age 30 and 90% by age 60
What does the Guardisill vaccine protect against?
HPV 16 and 18 but not the others
What is the number 1 cause of lung cancer?
Smoking
What is the most common cause of skin cancer?
UV radiation
What are the 10 hallmarks of cancer?
- Uncontrolled proliferation (self-sufficient)
- Evasion of growth suppressors (inactivation of tumor suppressors)
- Resistance to apoptosis
- Develop replicative immortality (activate telomerase)
- Induce angiogenesis
- Invasion and metastasis
- Changed energy metabolism (anaerobic)
- Immune system evasion
- Genomic instability
- Inflammation
Confined locally (doesn’t spread), easier to remove
Benign
What is angiogenesis and why is it important in cancer?
Forming new blood vessels. Tumors do it to feed themselves
Invades surrounding tissue, spreads to other parts of the body, often comes back
Malignant
What do mutations cause in a cell?
A pile up until the cell can no longer divide properly (the dividing genes are damaged)
What are the 3 basic types of oncogene activation?
Mutation which changes protein structure, increase in protein concentration, and chromosomal translocation
What types of genes are most often associated with cancer?
Oncogenes and tumor suppressors
Why is immunotherapy better than chemotherapy?
Immunotherapy delivers chemo to the cancer cells through the immune system so it saves more normal cells
Why is lung cancers 5 year survival rate only 18%?
It is often more advanced by the time it is diagnosed
What does the two-hit hypothesis say?
Both copies of the gene must be non-functional
What are high risk types of HPV linked to?
Cancers of the cervix, vulva, vagina, penis, anus, and mouth
What role does nicotine play in cancer?
It isn’t a carcinogen so it cant start the cancer but it does help cancer grow and prevent therapies
How do errors during replication and mitosis happen?
A chance when cells divide and the chance goes up with more divisions. Also, carcinogens
Do both tumor suppressor genes have to be non-functional for cancer to occur? What about oncogenes?
Tumor suppressors = both copies must be non-functional
Oncogenes = Only one must be non-functional
What is key in increasing the survivability of breast cancer?
Early detection
What cancer accounts for 26% of all cancer deaths
Lung cancer
What determines how many mutations it takes to cause cancer?
The genes that are being mutated
The most researched and important tumor suppressor
p53 “the guardian of the genome”
What are 2/3 of cervical cancers caused by?
2 strains of HPV (HPV 16 and 18)
Why does the risk of cancer increase with age?
The older you are, the more carcinogens you are exposed to and the more your cells have divided; you have longer to accumulate mutations
What are the two ways the cancer is caused?
mutations in the cells own DNA and viruses
What are oncogenes involved in?
Growth and differentiation
What are other causes of lung cancer?
Asbestos, radon gas, pollution, exposure to carcinogens (coal dust, gasoline, mustard gas), and radiation therapy to the lungs
What is mutated in about 50% of human cancers?
p53
What is gene therapy?
Cells resistant to chemo/radiation are introduced to normal genes that respond to them
Do viruses or mutations account for most cancers?
Mutations
What is the number 1 risk factor for cervical cancer?
HPV
What are carcinogens?
Substances that can cause cancer like UV light, caffeine, asbestos, alcohol, chemicals in cigarettes
What does a mutation which changes protein structure cause?
Increase in activity or causes a loss of regulation. Oncogene activation
Breaks for the cell cycle
Tumor suppressors
What is immunotherapy?
General boost to the immune system to help it recognize cancer cells. Attack specific targets. Deliver chemo to cancer cells
What percentage of all cancers cases are breast cancer?
14%
1 in 8 women develop an invasive form of this cancer
Breast cancer
8 types of cancer treatments
Resection, chemotherapy, radiation, bone marrow transplants, targeted therapies, immunotherapy, gene therapy, and cancer vaccines
What does a tan tell you?
DNA damage. Cells produce more melanin to protect the cells. Thymine dimer - T attaches to A next to it, not across from it
What are cancer vaccines?
Hepatitis B and HPV (prevent cancer)
Prostate (treat cancer)
A mass of cells that can be benign or malignant
Tumor
What does an increase in protein concentration cause?
Increase in expression, stability, or gene duplication. Oncogene activation
How does a virus cause cancer?
It could insert DNA to an oncogene by chance
What are targeted therapies?
Target specific pathways/proteins involved in tumor development. Ex: angiogenesis inhibitors, Herceptin, Gleevec, and tamoxifen
How many mutations need to happen on average for cancer to form?
8-10
What is a bone marrow transplant?
Chemo and radiation destroys bone marrow. Transplant needed to make new blood cells
What is resection?
Removal of tumor and surrounding tissue. Cancer treatment
Gene that when mutated or over expressed can contribute to turning a normal cell into a cancer cell
Proto-oncogene (normal versions of oncogenes)
What does melanin do?
Protects cells from UV radiation
What does the p53 gene do?
Regulates the cell cycle. Crucial in making sure cells don’t pass on mutated DNA
What is radiation?
Induce DNA damage to cause apoptosis
What percentage of cancers and due to viruses and what are some examples?
15%. HPV and hepatitis
Most common cancer in the US
Skin cancer
What does chromosomal translocation cause?
Constitutively expressed fusion protein (Bcr-Abl) or expression in wrong cell at wrong time. Chromosomes break off and swap places with one another. Oncogene activation
How does HPV cause cancer?
It produces a p53 inhibitor that deactivates the p53 protein which allows cells with mutated DNA to divide
What is chemotherapy?
Targets rapidly dividing cells. Causes nausea and hair loss bc hair and stomach cells are rapidly dividing
What tumor suppressors are involved in breast cancer?
BRCA 1 and BRCA 2
How many new cases of invasive breast cancer are diagnosed each year
About 250k with 2.4k being in men
Genes which have a repressive effect on the regulation of the cell cycle or promote apoptosis
Tumor suppressors
What percentage of breast cancer cases are linked to inherited gene mutations?
5-10%
What are known risk factors of breast cancer?
Smoking, obesity, alcohol, exposure to carcinogens, increased estrogen exposure
How many carcinogens are in cigarettes?
At least 70 confirmed
What does sunscreen do?
Spray and lotion molecules absorb and dissipate energy so it doesn’t harm DNA
What are examples of oncogenes?
Growth factors, RTKs, GTPases, transcription factors
