Infectious/Environmental Influences & The Warburg Effect Flashcards
What percentage of cancers are due to infectious causes?
15-20%
(T or F) Infectious disease as a cause of cancer is equally distributed between developed and developing countries.
False
Which of the following associations is incorrect?
a. Kaposi sarcoma and HIV
b. Bladder cancer and schistosomiasis
c. Nasopharyngeal cancer and EBV
d. Gastric cancer and EBV
d. Gastric cancer and EBV
What are mechanisms of infection-induced malignancy?
Chronic inflammation Immunosuppression Genomic instability Infection inducing cell proliferation Production of oncogenic proteins
What factors are associated with increased risk of H pylori infection?
Household crowding
Older age
Decreased household sanitation
By which mechanism is H pylori able to survive the acidic environment of the stomach?
Production of urease
(T or F) Individuals with H pylori are always symptomatic.
False
What factors are associated with the development of gastric carcinoma?
High sodium diet
Cigarette smoking
Host genetics
Strain virulence
Which of the following factors are NOT protective against the progression to gastric carcinoma?
a. H pylori infection
b. Antioxidant intake
c. Helminthic infection
d. All
e. None
a. H pylori infection
What is an indication for H pylori testing?
Workup for symptoms associated with a peptic ulcer
Which of the following is considered the gold standard for H pylori testing?
a. Histological ID following biopsy
b. Serum antibodies
c. Stool antigen testing
d. Urea breath test
a. Histological ID following biopsy
What are mechanisms by which hepatitis B causes hepatocellular carcinoma?
DNA integration
Production of oncogenic proteins
Chronic inflammation
By which transmission route do the majority of individuals contract chronic hepatitis B?
Birth
Hep B as in Babies
Which marker demonstrates vaccination for HBV?
HBsAB
You order a hepatitis B panel for someone you suspect to be infected. Which of the following results confirm your suspicion of a CHRONIC infection?
+ HBsAg
+ Total Anti-HBc
- IgM Anti-HBc
- Anti-HBs
Which population is most likely to clear an HBV infection?
Adults
What are risk factors associated with HCV transmission?
Multiple sex partners
IV drug use
Organ transplant recipients before the mid 80s
(T or F) HBV vaccination program in the US has led to a decrease in the incidence of hepatocellular carcinoma.
True
(T or F) People typically form immunity to HCV through antibody production.
False
What is the “window” from exposure to testing positive for HCV?
4 weeks
What percentage of cervical cancers are linked to high risk HPV infections?
90%
Which oncogenes are encoded in high-risk HPV genomes?
E6 and E7
What are risk factors for development of cervical cancer?
Smoking (2x) Early onset of sexual activity Low SES HIV After having 3+ children Long term oral contraceptive use
Which of the following screening guidelines for cervical cancer is correct?
a. Continue screening after hysterectomy regardless of history
b. Begin screening at 21yo independent of sexual activity
c. Co-screening for HPV and cytology from 21-29
d. Stop screening at 65 yo regardless of history
b. Begin screening at 21yo independent of sexual activity
(T or F) HPV vaccines protect against cervical cancer and only females should receive them.
False
By which mechanism are schistosomes believed to cause bladder cancer?
Chronic inflammation
What energy source do cancer cells use for aerobic fermentation?
Glucose
Which of the following is NOT a feature of the Warburg effect?
a. Increased glucose uptake
b. Lactic acid production in the presence of oxygen
c. Aerobic fermentation
d. Increased response to growth-inhibition
d. Increased response to growth-inhibition
What are flavins?
Materials used in the creation of FAD
What are actions of ATP in cellular metabolism?
Cellular division
Housekeeping fxns
Redox balance
Why is glycolysis an inefficient means of ATP production in mammalian white muscle?
Glycolysis produces lactic acid due to anaerobic metabolism inhibiting glycolysis
(T or F) Glucose is rate limiting in cellular metabolism.
False
(T or F) Glucose produces ATP faster (via glycolysis) than oxidative phosphorylation.
True
What percentage of glucose is diverted into biosynthetic pathways upstream of pyruvate in proliferating cells?
10%
What is the primary end product of glycolysis within proliferating tissue or tumor?
The majority of pyruvate is converted to lactate
What is the pyruvate kinase isoform PKM2?
Key metabolic regulator in rapidly dividing cells
What effect does reduction in PKM2 levels have on glycolysis?
Allows more glycolytic intermediates to be used for biosynthesis
Increased 3PG leads to an increase in which amino acid?
Serine
Increased 3PG leads to an increase in which amino acid?
Serine
Serine is converted to which amino acid when it donates a carbon to the folate pool?
Glycine
The functions of serine in the body include:
Increasing biomass
Producing nucleotides
What does glycine contribute to in the nucleotide structure?
1 nitrogen and 2 carbons
(T or F) Glutamine can be used by proliferating cells as a fuel source.
True
What are the roles/functions of glutamine in cellular metabolism of proliferating cells?
Carbon source for acetyl-CoA
Nitrogen source
Anaplerotic for the TCA cycle
In the Krebs Cycle of the proliferating cell, glutamine donates carbon to alpha ketoglutarate which is converted to _______________.
Citrate
Under normal conditions, acetyl-CoA derives the majority of its contributions from
Glucose
Under hypoxic conditions, acetyl-CoA derives the majority of its contributions from
Glutamine
The Warburg phenomena has suggested that __________- is a way of limiting rapid cell growth
Calorie restriction
(T or F) A large number of people in the population have genes coding for familial (hereditary) cancers.
False
Which of the following is NOT evidence to support the environmental-cancer link?
a. The majority of cancer cases have no known risk factors
b. Fewer than half of identical twins get the same cancer
c. Most cancer rates remain stable across the globe
d. Immigrant’s cancer risk parallels that of their new country
c. Most cancer rates remain stable across the globe
Which type of cancer is the most common in the US?
Carcinomas
Which fraction of yearly cancer deaths in the US are related to exposure to carcinogens in tobacco products?
1/3 (33%)
Obesity and physical inactivity may account for what percentage of severe major cancers?
25-30%
H. pylori contributes to the development of which type of cancer?
Stomach cancer
Exposure to elevated levels of radon gas are associated with which type of cancer?
Lung cancer
Which solvent is found in pain thinners, glues, and dry cleaning and is known to cause leukemia?
Benzene
Which fine particle is linked to increased rates of mesothelioma?
Asbestos
What are dioxins?
Unwanted byproducts of chemical processes containing chlorine and hydrocarbons
People are exposed to 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) through
Dairy, fish, meat
Which types of cancers are linked to polycyclic aromatic hydrocarbon (PAH) exposures?
Skin, lung, urinary cancers
What are sources of polycyclic of polycyclic aromatic hydrocarbons (PAHs)?
Wood burning stoves for homes
Smoked/BBQ foods
Sausages
(T or F) There are medical interventions to reduce blood lead levels (BLLs)
True
Diesel exhaust particles are suspected of being carcinogens due to the increased incidence of this type cancer in the occupational groups exposed to diesel exhaust?
Lung cancer
(T or F) Vinyl chloride can leach from plastic PVC bottles
True
What are known health effects of polychlorinated biphenyls (PCBs)?
Thyroid toxicity
Breast cancer
Developmental neurotoxicity
What are the primary routes of exposure to phthalates?
Personal care products, food, children’s toys
(T or F) Phthalates are endocrine disruptors in both males and females.
True
(T or F) More than 90% of the US population has measurable levels of BPA in their body.
True
