Vitamin D and Breast Cancer - Final Exam

Question 1

What are 2 complementary theories involved with the altered exposure to natural light and darkness that could lead to increase in breast cancer?

Answer 1

1. Decrease natural daytime light exposure leads to increase of breast cancer risk by depleting body levels of vitamin D and serotonin
2. Light exposure after sunset leads to increase breast cancer risk by decreasing the circadian production of melatonin

Question 2

What 2 factors influence the levels of estrogen?

Answer 2

1. Vitamin D

2. Melatonin

Question 3

VDR

Answer 3

Vitamin D receptor

Question 4

What does the VDR form with RXR?

Answer 4

Heterodimer on the VDRE on the DNA to affect transcription and production of proteins for cell differentiation and development and maintaining normal blood levels of Ca and P

Question 5

RXR

Answer 5

Retinoic X receptor

Question 6

VDRE

Answer 6

Vitamin D response element

Question 7

What are 4 roles of vitamin D?

Answer 7

1. Induces the expression of cell cycle arrest proteins and pro-apoptotic cell death proteins
2. Suppresses inflammation
3. Decreases the expression of aromatase
4. Downregulates the expression of ER-alpha, thus stimulation proliferation

Question 8

What are 2 cell death proteins?

Answer 8

1. Bax

2. Bak

Question 9

How does vitamin D suppress infalmmatrion? Example.

Answer 9

By inhibiting inflammatory enzymes

- eg) Cox-2

Question 10

What 2 factors does vitamin D inhibit in the estrogen pathway?

Answer 10

1. ER alpha

2. Aromatase

Question 11

What does vitamin D inhibit in the prostaglandin pathway?

Answer 11

Cox-2

Question 12

What 4 pathways help vitamin D to inhibit proliferation?

Answer 12

1. Cell cycle arrest
2. Proapoptotic pathway
3. Prodifferentiation actions
4. Anti-inflammatory

Question 13

What are 6 roles of vitamin D in decrease cancer risk and progression?

Answer 13

1. Proliferation
2. Apoptosis
3. Differentiation
4. Inflammatory
5. Invasion and metastasis
6. Angiogenesis

Question 14

What do transcriptional repression of ER alpha in breast cancer cells block?

Answer 14

Oestrogen stimulus

Question 15

What are low levels of vitamin D associated with?

Answer 15

Increase in breast cancer

Question 16

What kind of UV exposure produces vitamin D?

Answer 16

UV-B

Question 17

When does vitamin D naturally peak?

Answer 17

Later afternoon

Question 18

What 4 factors naturally increase in the later afternoon?

Answer 18

1. Vitamin D
2. Serotonin
3. Body temp
4. Higher levels of sunlight

Question 19

What do many people today have a deficiency in?

Answer 19

Vitamin D

Question 20

What are higher levels of vitamin D associated with?

Answer 20

Decrease in breast cancer risk

Question 21

If vitamin D is low then what else is typically low?

Answer 21

Serotonin

Question 22

What 2 factors downregulate estrogen signalling? And whats the result?

Answer 22

1. Melatonin
2. Vitamin D
   - Result = decrease in breast cancer risk

Question 23

What do low levels of melatonin and vitamin D allow?

Answer 23

Increase in estrogen signalling