Breast Cancer and Tissue Engineering (25,28)

Question 1

Which method would NOT be used to define mammary stem cells?

a. Limiting dilution assays
b. Transplantation to demonstrate the multilinage differentiation capacity of stem cells
c. In vitro linage tracing
d. Fractionation by flow cytometry using cell surface markers

Answer 1

c. In vitro linage tracing

Question 2

How was self-renewal shown in Lin- CD24+ CD29hi cells?

a. Serial transplantation studies
b. Bipotent exclusion
c. In vivo linage tracing
d. B-gal assay

Answer 2

a. Serial transplantation studies

Question 3

How do ovarian hormones influence stem cell activity?

a. Depriving the hormones increases MaSC activity
b. The MaSC pool increases during pregnancy
c. Aging leads to a decrease in MaSC function
d. Excess hormone levels decrease MaSC function

Answer 3

b. The MaSC pool increases during pregnancy

Question 4

What is RANKL?

a. A ligand that leads to stem cell expansion
b. A luminal progenitor upregulated in breast cancer
c. A compound secreted from the alveolar myoepithlium
d. A steroid hormone that signals stem cell differentiation

Answer 4

a. A ligand that leads to stem cell expansion

Question 5

The transcription factor GATA3:

a. Is dispensable in the process of luminal cell differentiation
b. Only regulates mammary gland development in the embryo
c. Influences development, cell fate and differentiation
d. Is a master regulator of the RANK pathway

Answer 5

c. Influences development, cell fate and differentiation

Question 6

What is correct about BRCA-1 mutations?

a. Luminal progenitors exhibit factor-independent growth
b. Colony forming ability is damaged
c. The mutation directly impacts stem cell activity (no, progenitor)
d. Luminal progenitors only proliferate in the presence of growth factors

Answer 6

a. Luminal progenitors exhibit factor-independent growth

Question 7

What best describes how APC can link to tumour formation in the gut?

a. Tumours arise when APC is deleted in transit amplifying cells
b. Tumours arise when APC is up-regulated in stem cells
c. Tumours arise when APC is deleted in stem cells
d. Tumours arise when APC is deleted from stem cells and transit amplifying cells

Answer 7

c. Tumours arise when APC is deleted in stem cells

Question 8

What is NOT a feature of cancer stem cells?

a. They are subsets of tumour cells that can self-renew and generate tumour cells
b. They are the same as the ‘cell of origin’
c. They do not necessarily originate from transformation of normal stem cells
d. They can be demonstrated through serial transplantation experiments

Answer 8

b. They are the same as the ‘cell of origin’

Question 9

• During pregnancy, the breast epithelium can expand 25 fold.

Answer 9

T

Question 10

• Confetti is a multicolour cre reporter that allows one cell to fluoresce many colours.

Answer 10

F

Question 11

• Only mouse MaSCs lack receptors for the ovarian hormones oestrogen and progesterone.

Answer 11

F

Question 12

• Unlike notch signalling, Wnt signalling is essential for the self-renewal of MaSCs.

Answer 12

T

Question 13

• CD61 cells are 20-fold enriched for CSCs.

Answer 13

T

Question 14

What is not a hurdle in tissue engineering?

a. Technical considerations
b. Commercial considerations
c. Advertising regulations
d. Regulatory considerations

Answer 14

c. Advertising regulations

Question 15

Which statement is FALSE?

a. The design criteria of engineered tissue is based on specific tissue properties
b. 3D human scale tissues do not require an early blood supply
c. In vivo bioreactors allow construct development concurrently with vascularisation
d. Traditional tissue engineering is based on making a polymer scaffold, introducing cells and growth factors and transplanting it to the patient

Answer 15

b. 3D human scale tissues do not require an early blood supply

Question 16

What is NOT a challenge in tissue engineering?

a. Biomaterials must not be biodegradable
b. 3D vascularised tissues require a blood supply
c. Biological signals must be delivered efficiently
d. Infection and in vivo responses must be controlled

Answer 16

a. Biomaterials must not be biodegradable

Question 17

What is correct about Macroporous hydrogel production?

a. Porosity and interconnectivity are low
b. Average pore size cannot be tuned by temperature
c. The process involves a freezing and warming cycle which causes water molecules to leave holes in the material
d. The resulting scaffold can be toxic to human recipients

Answer 17

c. The process involves a freezing and warming cycle which causes water molecules to leave holes in the material

Question 18

What is NOT a feature of layer by layer assemblies?

a. bFGF can be delivered sandwiched with Heparin in a microsphere
b. Surface chemistry is important for cell adhesion and can be manipulated through crosslinking
c. PLGA can lead to inflammation but can be used as a base layer for engineered tissue scaffolds
d. When bFGF is in a microsphere, it is released rapidly and is not tunable

Answer 18

d. When bFGF is in a microsphere, it is released rapidly and is not tunable

Question 19

In regards to dual biomolecule delivery:

a. α-MSH binds strongly to hydrophobic surfaces and can act as an anti-inflammatory when PLGA is broken down
b. Increasing the amount of crosslinking slows the release of α-MSH
c. bFGF is stabilised by specific binding between heparin and HA
d. Increasing the number of layers slows the release of bFGF

Answer 19

a. α-MSH binds strongly to hydrophobic surfaces and can act as an anti-inflammatory when PLGA is broken down

Question 20

• The mechanical properties of cells and/or tissues can be characterised using micropipette aspiration, AFM and Instron Microtesters.

Answer 20

T

Question 21

• Increasing hyaluronic acid content decreases the bulk stiffness of polymer scaffolds.

Answer 21

F

Question 22

• PLGA is a hydrophobic polymer with poor surface chemistry and can induce inflammation.

Answer 22

T