BIO 302: EXAM 2 Study Guide
How to calculate someone's pack-year amount/risk?
(# of packs per day) x (# of yrs they've been smoking)
What are the risk factors for cancer that CANNOT be altered?
-Age -Genetics (gender, ethnicity, inherited mutations, inherited immunodeficiency) -family history -personal history -world region (move to a new country, acquire risk for that new country)
Explain the current vaping situation in the US and the dangers it imposes.
-Most current smokers (70%) use vaping to try to quit smoking but vaping is associated with smoking relapse. -Never smokers who vape are young (63% are 18-24). Brain is still developing, but nicotine affects brain development. Increased risk of smoking cigarettes when they are older -can cause EVALI (E-cig or Vaping product use- Associated Lung Injury): Severe/ fatal lung disease that arises suddenly in otherwise healthy people. Causes lungs to stop functioning altogether.
What are the risk factors for cancer that can be treated/prevented?
-chronic inflammation -viral infections -bacterial infections -dietary deficiencies -diabetes -hormonal status -smoking/tobacco -obesity -alcohol -nutrition/diet -physical activity -exposures to carcinogens
How does obesity cause cancer?
-excess production of estrogen by fat cells: causes increased cell proliferation -increased insulin levels and insulin like growth factors -fat cell production of adipokines (cytokines): stimulate cell growth, decrease apoptosis, and increase inflammation (inflammation produces ROS, which induce mutations) -causes oxidative stress: imbalance between ROS (free radicals) and anti-oxidants) -chronic inflammation: (inflammation produces ROS, which induce mutations)
Summary of mechanisms of dietary substances to reduce cancer: ** this is more of a summary/note flash card**
-protection against DNA damage -inactivation of carcinogens -anti-viral and anti-bacterial activity -anti-inflammatory activity -induction of apoptosis in mutated cells -inhibition of angiogenesis -inhibition of cell proliferation -inhibition of cancer cell migration -binding of polycyclic hydrocarbons in the gut, inhibiting uptake
What are the many steps of metastasis described by Dr.Maley?
-tumor cells have to leave their original site -they have to invade into the blood vessel (and survive) -they have to stick somewhere else -they have to invade back out of blood vessel into the tissue -now they are in a new environment with new hormones, different from where they came from. Many are unable to grow and survive in new environment -when they do grow and manage a signal for angiogenesis, metastasis happens.
Viruses associated with human cancers: ** more of a notes slide **
1. Hep B/ Hep C= Hepatocellular carcinoma 2. HPV= cervical, anal canal, and head and neck carcinomas 3. Epstein Barr virus (EBV)=Burkitt/other B-cell lymphomas, and Nasopharyngeal carcinoma 4. Human T-cell Lymphotrophic virus: adult T-cell leukemia 5. HIV (permissive for secondary carcinogenic virus infection but isn't directly causal)= lymphomas, Kaposi's sarcoma, anogenital carcinoma -mutagenic viruses insert their own DNA into chromosomes of host cells
Explain how the following food substances act to decrease the risk of cancer: Sulforaphane/Indole-3-carbinol, carotenoids, polyphenols, plant fiber, and curcumin.
1. Sulforaphane and Indole-3-carbinol are found in cruciferous vegetables. Sulforaphane inhibits growth and spread of cancer cells. Indole-3-carbinol inhibits the cell cycle of cancer cells. 2. Carotenoids are found in red/orange/yellow/green vegetables and they act as anti-oxidants to prevent free radical damage to DNA. 3. Polyphenols aka phytochemicals are found in fruits and vegetables and they also act as anti-oxidants. 4. Plant fiber shortens gut transit time which is beneficial because waste contains carcinogens so it's better to get it out faster to reduce exposure. 5. Curcumin is a spice that modulates gene expression: Inhibits proliferation of tumor cells in vitro, decreases inflammation, and has anti-angiogenic activity.
All of the following are causal risk factors for cancer EXCEPT: A. Asbestos B. Age C. Cigarette smoke D. UV light exposure
A
For which of the following is there a screening test that reduces the number of deaths from that cancer and causes few harms to screened persons? A.) Cervical cancer and colon cancer B.) Liver cancer and cervical cancer C.) Colon cancer and breast cancer D.) Breast cancer and prostate cancer
A
When studying a suspected carcinogen, researchers do the following, EXCEPT: A.) Intentionally expose human subjects to the suspected carcinogen B.) Let people behave as they normally would and observe outcomes C.)Work closely with the IARC, NTP, and EPA D.) Intentionally expose animals to the suspected carcinogen in controlled studies
A
_______________ and smoking are the greatest risk factors for cancer world-wide. A. Diet/obesity B. Viruses C. Alcohol D. UV radiation
A
Which of the following contributes to the confusion associated with the mammography screening test? A.) Inconsistency of information between different screening authorities B.) Women are not educating themselves on breast cancer screening C.) The test being legal in some states and illegal in others D.) Doctors using the screening test while all screening authorities suggest not to use it
A Explanation:
Explain the relationship between risk factors and causal factors
A risk factor is a a characteristic, condition or behavior that increases the probability of cancer, whereas a causal (risk) factor directly causes mutation. A risk factor may or may not be a causal factor for cancer. Examples: A causal (mutation cauing) risk factor could be asbestos exposure. A non-causal (non-mutation causing) risk factor would be age. Risk factors vary in the degree of risk they impose.
A relative risk of ______ means you have a 75% higher risk of cancer than the average. A. 0.75 B. 1.75 C. 7.5 D. 175
B
All of the following are examples of ionizing radiation, which can increase risk of cancer EXCEPT: A. UV radiation B. Microwaves C. Gamma radiation D. X-Rays
B
All of the following are tests that are most effective as screening tools for cancer EXCEPT: A. Pap smear (uterus/cervix exam) B. Mammography (breast exams) C. Colonoscopy (colon exams) D. Low dose computed tomography (lung exam)
B
As false negatives go up, the NPV ______. A.) Increases B.) Decreases C.) Stays the same D.) None of the above
B
Obesity is linked with all of the following hormonal abnormalities EXCEPT: A.) Excessive Production of Estrogen B.) Excessive production of Oxytocin C.) Increased Insulin levels D.) Increased production of Adipokines
B
Somatic mutations: A. Occur in germline cells B. Occur in non-germline cells C. Can be inherited D. Cause cancer family syndrome
B
The most common type of leukemia in children is: A.) Acute myelogenous leukemia B.) Acute lymphocytic leukemia C.) Chronic myelogenous leukemia D.) Chronic lymphocytic leukemia
B
What is the major consequence of using the "maximum tolerated dose" approach to cancer therapy? A.) It often isn't toxic enough to kill cancer cells B.) It selects for cancer cells resistant to the therapy C.) The therapy kills the patient D.) It causes the cancer to grow larger before dying
B
Which of the following is NOT a characteristic of test sensitivity? A.) It is the ability of the test to correctly identify patients with the disease B.) It does not take false negatives into account C.) It is derived from clinical evaluations with a fixed proportion of diseased persons D.) It is 100% sensitive if it produced a positive result in all individuals with the disease
B
Which of the following mutated precursor cells is associated with Acute Myelogenous Leukemia (AML)? A. Lymphoid precursor B. Myeloid precursor C. Hematopoietic precursor D. Megakaryoblast precursor
B
Which of the following tests pose the LEAST amount of risk for the patient? (Safest) A.) PET scan B.) MRI C.) X-Ray D.) CT or CAT scan
B
_______________ is 14x more likely to have residents with stomach cancer. A. US B. Japan C. China D. Uganda
B
what BMI score qualifies as obese?
BMI of 30
A test that reads positive of a person who did not have the disease would be referred to as a ____________ test? A. True positive B. False Negative C. False Positive D. True negative
C
All of the following are examples of genetic susceptibility EXCEPT: A.) Inherited efficiency of DNA repair function B.) Inherited efficiency of immune function C.) Inherited mutation of tumor suppressor gene D.) Inherited variation in skin pigmentation
C
All the following are risk factors for cancer that cannot be altered EXCEPT: A.) Age B.) Genetics C.) External Environment D.) Family History
C
Information that can be gained from imaging includes all of the following EXCEPT: A.)Tumor location B.)The size of the tumor C.)The clinal heterogeneity in the tumor D.)Tumor metastases
C
The idea of giving more of the effective drugs that results in a stronger effect, is associated with ________. A.) Therapeutic Effect B.) Toxic Effect C.) Dose-Response Curve D.) Clinical Trials
C
Which two risk factors account for more than half of all environmentally caused cancers? A.) Smoking and radiation B.) Infections and obesity C.) Smoking and obesity D.) Smoking and infections
C
Why is "age" described as a non-causal risk factor rather than a causal risk factor? A.) Increased age is a known carcinogen B.) Age causes mutations which cause cancer C.) Age increases the timeframe for exposure to carcinogens D.) Increased age is synonymous with decreased risk for acquiring mutations
C
Explain the environmental factors and how they contribute to cancer
Cancer is mostly an environmental disease because 90-95% of cases are attributed to environmental factors, while only 5-10% are due to genetics. Most common environmental factors contributing to cancer in the US includes: Tobacco (25-30%), Diet and obesity (30-35%), Infections (15-20%), Radiation (both ionizing and non-ionizing- up to 10%) and environmental pollutants.
Explain the relationship between carcinogens and mutagens
Carcinogens are agents that either cause or promote cancer. Some carcinogens directly affect DNA (called mutagens) and others indirectly. Mutagens are agents that directly alter/damage/mutate the DNA. An example of a carcinogen that indirectly affects DNA are hormones which promote mutation by increasing cell division. In conclusion, all mutagens are carcinogens but not all carcinogens are mutagens.
All of the following are dose-dependent factors EXCEPT: A. Amount of red meat eaten per week B. Amount of alcohol consumption C. Amount of physical exercise done D. Amount of cruciferous vegetables eaten
D
All of the following are examples of common childhood cancers EXCEPT: A.) Acute Leukemias B.) Neuroblastomas C.)Brain and Spinal Cord cancers D.) Carcinomas
D
All of the following are examples of imaging tests EXCEPT: A.) X-Ray B.) MRI C.) Ultrasound D.) Digital palpation
D
All of the following are forms of screening for colorectal cancer EXCEPT: A. Colonoscopy B. Sigmoidoscopy C. Stool-Based Tests D. Urinalysis
D
All of the following are group 1 carcinogens (definitely carcinogenic to humans) EXCEPT: A. Alcohol B. Tobacco C. Engine Exhaust, diesel D. Obesity
D
All of the following are risk factors that can be altered ECEPT: A. Obesity B. Physical activity C. Tobacco use D. Personal History
D
All of the following dietary factors can increase cancer risks EXCEPT: A.) Foods that are high in fat B.) Foods that are highly processed and preserved C.) High omega-6 fats to omega-3 fats ratio D.) Foods that are high in fiber
D
The likelihood of getting cancer may be dependent on which of the following: A.) Susceptibility of the individual (genetic background) B.) Mode of exposure C.) Duration and/ or frequency of exposure D.) All of the above are correct
D
What is the gold standard for definitive diagnosis of cancer? A. Signs and symptoms B. Blood and urine tests C. Radiological tests D. Pathological tests
D
Which of the following does not affect the rate of evolution? A. Mutation rate B. Population size (quantity) C. Heritability D. Population size (mass)
D
Which of the following technologies use sound waves to create a 2D image based on the distances and intensities of the echoes? A.)Mammography B.)X-ray C.)Magnetic resonance imaging D.)Ultrasonography
D
Which type of bias overlooks the need to compare like disease types and biological aggressiveness? A. Confirmation bias B. Lead time bias C. Attribution bias D. Overdiagnosis bias
D
Why is breast cancer screening considered a problematic screening test? A.) There is a high false positive rate B.) The test method uses a carcinogen C.) There are conflicting guidelines for using the test D.) All of the above
D
Carcinogens are usually causal for specific cancers, not all cancers. No carcinogen causes cancer predictably, all the time, in any individual, under any circumstances. The likelihood of getting cancer may be dependent on which of the following: A. the susceptibility of the individual B. the mode of exposure C. the duration and/or degree of exposure D. All of the above
D.
What solution/mechanisms do elephants have to Petos paradox?
Dr.Maley explains that they have 40 copies of TP53 (38 of them are nonfunctional retro genes) whereas humans have 2. Also, their cells are more susceptible to apoptosis when exposed to carcinogens like ionizing radiation than human cells are. This is how they evolved ways to prevent cancer/mutations.
Hormones are a common type of mutagen. True or false?
False
Ionizing radiation is a known carcinogen, but it is not a mutagen. True False
False
Peto's Paradox states that the incidence of cancer is directly correlated with the number of cells in an organism. True or False?
False
T/F: An individual that smokes is likely to have a relative risk of 1.
False
T/F: If the PPV is less than 0.5, this means that there are more true positives than false positives
False
T/F: The majority of cancers are caused by the inheritance of mutated tumor suppressor genes.
False
T/F: There is an effective screening method for most types of cancer
False
True or False: Cancer screening effectiveness is NOT dependent on cancer biology or cancer type.
False
True or False: False negative tests lead to over-diagnosis, over treatment and needless burden for patients and the healthcare system.
False
True or False: The Diagnostic Threshold (DT) will always divide the true positives from the false negatives.
False
T/F: The death rates from heart disease, cerebrovascular diseases, pneumonia, AND cancer have all dramatically decreased since the 1950s.
False Dr.Maley explains that the death rates have decreased dramatically for all those diseases except for cancer (despite our advances in technology and science). It is also different for different types of cancer
T/F: An initiating mutation is environmental while a mutation during progression can be inherited or non-inherited.
False Explanation: It's backwards- initiating mutations are inherited or non-inherited while mutations in progression are environmental
T/F: Vitamins/minerals/ supplements have been proven to decrease the risk of cancer.
False Explanation: Many studies have been conducted on vitamins (e.g. vitamin B6, B12, E, C, D, Beta-Carotene, Folic acid, and selenium) but they did NOT show a decreased risk of cancer. Selenium and Vitamin E Cancer Prevention Trial (SELECT) found that taking vitamin E alone increases risk of prostate cancer (but taking it with selenium did not increase the risk) NCI study found that vitamin E increased lung cancer risk and no vitamin reduced it.
True or False: The causes of most pediatric cancers are known.
False Explanation: The cause of most pediatric cancers are UNKNOWN because they are not related to lifestyle like adult cancers, only 4% of federal funding for cancer research goes to pediatric cancer, and companies don't invest in drug development because its not profitable.
T/F: Lung cancer is decreasing for never-smokers as well as smokers.
False Explanation: While lung cancer death rates are decreasing as well as cigarette consumption in the United States, lung cancer in never-smokers is actually on the rise. Some statistics: - 2020 study found 84% of women & 90% of men with new diagnosis of lung cancer never smoked - 12% of lung cancer patients in US have never smoked - We may need to revise current screening guidelines which currently they recommend for people 50+ with a 20 pack-year smoking history -worldwide: lung cancer in never smokers comprises an estimated 15-20% of cases in men and over 50% in women.
T/F: Genetic susceptibility is an inherited mutation.
False Explanation: genetic susceptibility is an inherited factor but that is not the same as an inherited mutation. An inherited mutation is when there is a germline mutation in the DNA that is passed to offspring. An example of genetic susceptibility would be how efficiently your normal DNA repair enzymes work.
Which of the following dietary components does not increase your risk for cancer? A. High fat B. Processed meats (smoked, cured, salted, preserved)/ red meat C. Concentrated sugar and refined flour products D. Ratio of omega-3 (protective) and omega-6 (CA-promoting) fats E. Low Fiber F. Beta-Carotene; vitamin E, selenium, folate G. Fruits and vegetables
G Explanation: All the others increases the risk for certain cancers, but fruits and vegetables show strong evidence of decreasing the risk of cancer.
What is the IARC classification of carcinogenic agents (Group 1-4)?
Group 1: Carcinogenic to humans Group 2A: Probably carcinogenic to humans Group 2B: Possibly carcinogenic to humans Group 3: Unclassifiable as to carcinogenicity in humans Group 4: Probably not carcinogenic to humans
Ionizing vs non-ionizing radiation
Ionizing: Ultraviolet light (sun), x-rays gamma rays Nonionizing: AM/FM, tv, microwave, cell phones, radar
How does physical activity lower the risk of cancer?
Mechanisms likely related to: energy balance, hormone metabolism, insulin regulation, increased gut transit time, modulation of immune and inflammatory systems -strong association with lower risk of colon, breast, and endometrial cancer, but also associated with lowering risk of many other types of cancers.
How does alcohol increase the risk for cancer?
Mechanisms: - liver converts EtOH to acetaldehyde, which causes DNA damage and blocks normal DNA repair. -acetaldehyde stimulates liver cell division -EtOH increases estrogen production -EtOH causes cirrhosis via chronic inflammation -EtOH increases absorption of carcinogenic chemicals from tobacco -EtOH depletes folate (needed for normal production of DNA and RNA) -EtOH increases production of ROS, which directly cause DNA damage
What are the guidelines for moderate and heavy drinking?
Moderate:1 drink/day for women; 2 drinks/ day for men Heavy drinking (increases risk of cancer) : >3 drinks any day or >7/week for women; >4 drinks any day or >14 drinks /week for men
__________ clinical trials use randomized, placebo controlled tests to determine drug efficacy. A. Phase 1 B. Phase 2 C. Phase 3
Phase 3
Explain Relative Risk (RR)
RR of 1.0= average risk of cancer RR of 0.5= risk is 1/2 of the average/ 50% lower risk of getting cancer RR of 1.5= risk is 50% higher than the average RR of 10= risk is 10x the average risk (900% higher risk)
All mutagens are carcinogens, but not all carcinogens are mutagens. True or False?
True
Cancer risk and body mass index (BMI) are directly correlated. True or False?
True
Evidence that natural selection is occurring in cancer comes from the evidence that the same phenotypes emerge over and over again in tumors from different people. True or false?
True
More than 50% of all cancer can be prevented. True or False?
True
Not all agents have to be proven as causal in order to be labeled as a "carcinogen". True or False?
True
T/F: Acetaldehyde, converted from EtOH and derived from alcohol, is a causal, mutation-causing factor?
True
T/F: Although colonoscopy is effective, there are risks of missing the cancer or even having serious complications.
True
T/F: In the IARC's carcinogenic ranking system, group 1 agents are more likely to cause cancer than group 4 agents.
True
T/F: Initiating causes are unknown for many cancers.
True
T/F: Screening involves testing people without symptoms since cancer does not have many disease specific symptoms
True
True or False: Signs and symptoms can point to the source of health concerns but many are nonspecific.
True
True or False: There is a direct correlation between age of women and mammography sensitivity.
True
True or false: Most survivors of pediatric cancer will develop chronic health conditions related to the cancer or treatment
True
True or false: Positive stool-based tests require direct visualization for confirmation.
True
Tumors develop resistance to second therapies quicker than they do for first-line therapies. True or false?
True
Where you live can be a major contribution in risk factors for cancer. True or False?
True
T/F: For oncogenes mutations are dominant, while in tumor suppressor genes they are recessive.
True Explanation: If one copy of a normal proto-oncogene becomes mutated, the mutation is expressed. If one copy of a tumor suppressor gene is mutated, the mutation is not expressed unless the second normal copy of the gene also becomes mutated.
Explain cancer initiating mutations
Usually they are acquired (non-inherited) in somatic cells and caused by either environmental factors (which can be prevented), or by normal innate biological processes like DNA repair/replication error or toxic substances from inflammatory cells (less preventable). Less commonly, they are inherited through a germline mutation (mutation in sperm/egg that is passed to child) and present in every stem cell in the body. These initiating mutations cannot be prevented, but progression can. These can cause family cancer syndrome.
What was discovered in the 60s in regards to CML (chronic myelogenous leukemia)?
cytologists noticed a strange translocation in people with CML: a piece of chromosome 9 went and attached to the bottom of chromosome 22 & it became known as "the philidelphia chromosome" (discovered by Peter Nowell). They noticed over time in the same patients, they would still have the philidelphia chromosome, but would also aquire other chromosomal abnormalities such as an extra copy of the philidelphia chromosome, or another copy of chromosome 8, 6, and 19 (triploid).
when did cancer likely arise?
early multicelluar organisms **Petos paradox**
All carcinogens have the ability to affect DNA directly. True or false?
false
It's hard to kill cancer without killing the patient. Explain Dr.Maleys slide about clinical trials.
phase 1 clinical trials is meant to find the maximum tolerated dose. It usually involved 10-20 patients who start with low dose and then ramp it up, they carefully monitor for toxicity and get it to the point where the drug is killing more people than the cancer... then they back off slowly. (bring people to the brink of death in order to kill their cancer) phase 2 clinical trials may have 50-100 patients with different cancers, and they are looking for some hints that the drug is effective. phase 3 clinical trial (definitive trial): 100s to thousands of patients, choose a cancer to test, and give some people placebo and some people real version of drug to test its effectiveness. Success is measured by whether or not their life was extended for months or so by taking the drug.
when did cancer first appear?
probably about 2 billion years ago when the first multicellular organisms appeared and about 500 million years ago all major forms of animals appeared on earth. Somewhere around this
What is Peto's paradox?
the incidence of cancer does not seem to correlate with the number of cells in an organism Dr.Maley explains that humans have 1000x more cells than mice and live much longer, while whales have 1000x more cells than humans and live much longer. One might assume that the number of cells and life expectancy would correlate to the amount of cancer/ the incidence of cancer in these organisms. The more cells= the more chance for mutation. However, this idea is false and the incidence of cancer does NOT correlate to the number of cells in an organism.
