Topic 5 - Diet & Cancer (PART B)

Question 1

What are benign tumours?

Answer 1

cancer cells that do not spread beyond the immediate area in which they arise - are not dangerous

become malignant when they start to spread into surrounding areas

Question 2

What are oncogenes?

Answer 2

An oncogene is a mutated gene that has the potential to cause cancer. Before an oncogene becomes mutated, it is called a proto-oncogene, and it plays a role in regulating normal cell division.

Question 3

What is a tumour suppressor gene?

Answer 3

normal genes that slow down cell division or tell cells to die at the right time (a process known as apoptosis or programmed cell death).

when tumor suppressor genes don’t work properly, cells can grow out of control, which can lead to cancer.

they also repair mismatched DNA

Question 4

What are sporadic cancers?

Answer 4

cancers that occur because of acquired mutations

• are the most common causes of cancer

Question 5

What are germline mutations (inherited cancer)?

Answer 5

passed directly from a parent to child (found in every cell of body)

Question 6

Examples of tumour suppressor genes

Answer 6

BRCA1, BRCA2, p53

Question 7

When a tumour suppressor gene is mutated, what happens?

Answer 7

cells grow uncontrollably and may eventually form a mass called a tumour

Question 8

What are 2 common oncogenes?

Answer 8

HER2 –> specialized protein that controls cancer growth and spread - found on some cancer cells (e.g. breast and ovarian cancer cells)

The ras family of genes –> make proteins involved in cell communication pathways, cell growth, and cell death

Question 9

What are oncogenic viruses?

Answer 9

they transfer their genetic material to other cells and then remain in the body for a long time as a latent infection

Question 10

What is one characteristic of oncogenic infections?

Answer 10

• they encourage cells to reproduce at an unusually fast rate, which may damage the genetic material in those cells

-

Question 11

Examples of oncogenic infections

Answer 11

• hepatitis B or C (damage the body slowly, over many years)
• Epstein-Barr virus

Question 12

Why does cancer develop in some people who have had oncogenic infections but not others?

Answer 12

because other factors, such as smoking or exposure to other carcinogens, may be needed to trigger the final change of a normal cell into a cancer cell

also each person’s individual genetic makeup can differ

Question 13

What is the difference in presence of infectious agents in developed and less-developed countries?

Answer 13

22.9% vs 7.4%

Question 14

What is one important advance in cancer prevention in the past decade?

Answer 14

• the development and implementation of HPV vaccination to prevent cervical cancer
• a priority should be to ensure that the vaccine reaches the populations with the highest prevalences of HPV infection and cervical cancer

Question 15

Reduced exposure to occupational carcinogens, like aromatic amines or asbestos, have led to reductions in . . .

Answer 15

mesothelioma risk
bladder cancer

Question 16

Preventative recommendations (Word Cancer Research Fund and American Institute for Cancer Research)

Answer 16

• be lean
• be physically active
• eat a variety of fruits, veg, wholegrains, pulses
• limit alcohol consumption
• don’t smoke

Question 17

Don’t eat foods high in. . .

Answer 17

ENERGY

Question 17

Compliance with the WCRF recommendations has been associated with. . .

Answer 17

• a reduction in overall cancer risk (5%)
• with larger reductions for colorectal (12%) and stomach (16%) cancers

Question 17

Epidemiological evidence suggests that fruit & veg offer only _____ to limiting total cancer burden, mainly limited to cancers of the digestive tract

Answer 17

a modest contribution

Question 17

What are some important areas of research?

Answer 17

• improvement in methods used to assess diet
• consideration of diet throughout life course
• an analysis of how the host microbiome and genome interacts with dietary patterns and nutrients to modulate riske

Question 17

What are some important but uncertain areas of potential public health importance (environmental carcinogens)?

Answer 17

• non-occupational exposure to pesticides
• effect of electromagnetic fields

Question 18

Why is a reductionist approach to dietary studies ineffective?

Answer 18

• we shouldn’t focus on specific nutrients
• we should focus on the complex interactions bw genetic, epigenetic, metabolic, and gut-microbial processes that will inform our knowledge of the diet-cancer relationship

Question 19

Estimates suggest that only
_____ of a person’s lifetime risk of getting cancer results from uncontrollable factors

Answer 19

less than 30%

Question 20

What 4 lifestyle areas did the Harvard researchers examine?

Answer 20

• smoking
• drinking
• weight gain
• lack of exercise

Question 21

What did the Harvard study find?

Answer 21

• found that men could delay 67% of cancer deaths and prevent 63% of new malignancies each year by having a good lifestyle
• could reduce bladder cancer, prostate cancer, kidney cancer

Question 22

GI study - what was found?

Answer 22

consuming foods with a high GI (70 or higher) was associated with an 88% greater risk for prostate cancer

low GI foods (beans, lentils, peas) = 32% lower risk of both prostate and colorectal cancer

Question 23

What are some examples of high GI foods?

Answer 23

soft drinks
fruit juices
processed foods like pizza

Question 24

High dietary GI and high carbohydrate intake from high GI foods are associated with. . .

Answer 24

an increased risk of COLORECTAL cancer

Question 25

What was found in the Dutch study?

Answer 25

A major risk factor was inadequate dietary fibre intake and inadequate fruit and veg consumption will contribute more

Question 26

The International Agency for Research on Cancer classifies _____ meat as a cause of cancer, and _____ meat as a probable cause of cancer

Answer 26

processed

red

small effect for both generally

Question 27

How might red & processed meat cause cancer?

Answer 27

Red and processed meat contains a red pigment called haem, which could irritate or damage the cells in the body

the cells divide much more than normal to compensate for this damage

this increases the chance that one of the cells could acquire changes that cause cancer

Haem could stimulate the bacteria in our guts to produce chemicals called N-nitroso compounds

Question 28

Why are nitrates and nitrites added to processed meat?

Answer 28

• to preserve the meat
• nitrite and nitrates can be converted into N-nitroso compounds during the curing process & in the body

Question 29

High-fat diets COULD promote carcinogenesis via _______ ?

Answer 29

insulin resistance

Question 30

The cancers associated with high meat consumption could be reduced through a number of ways. List a few

Answer 30

• by addition of anticarcinogens in the diet esp at the same time as meat prep or meat consumption
• the modification of food preparation methods

Question 31

What are potential anticarcinogens found in meats?

Answer 31

• omega-3 PUFA
• conjugated linoleic acid (CLA)
• selenium
• vitamin B6 & B12
• vitamin D