A cancer cell line obtained from a rat glioma tumour was stained with the nuclear dye Hoechst 33342 and sorted using FACS. About 0.4% of the population stained lightly (LSP), distinct from the densely stained population of cells (DSP). Equal number of cells from these two populations were subcutaneously implanted into a suitable animal model to develop tumours. Following statements are made from this experiment:

A. The LSP cells will give rise to tumours.
B. The DSP cells will give rise to tumours.
C. The LSP cells can give rise to LSP and DSP cells.
D. The DSP cells can give rise to LSP and DSP cells.

Which one of the following options represents the combination of all correct statements?

Correct option is B

Explanation of the Correct Answer:

1. Statement A: The LSP cells will give rise to tumours.

   • This is correct. The LSP cells (lightly stained population) are likely to be stem-like cells or cancer stem cells. These cells have the potential to initiate tumours when implanted into a suitable animal model, which is commonly observed in glioma and other tumour models.

2. Statement B: The DSP cells will give rise to tumours.

   • This is incorrect. The DSP cells (densely stained population) are generally more differentiated and do not typically have the ability to initiate tumours. These cells are less likely to form tumours on their own since they are not stem-like or self-renewing.

3. Statement C: The LSP cells can give rise to LSP and DSP cells.

   • This is correct. LSP cells, as cancer stem cells, have the ability to differentiate into both LSP cells (maintaining the stem cell population) and DSP cells (more differentiated cells). This is a characteristic of cancer stem cells, which have both self-renewal and differentiation properties.

4. Statement D: The DSP cells can give rise to LSP and DSP cells.

   • This is incorrect. The DSP cells are more differentiated and lack the ability to self-renew or differentiate into LSP cells (stem-like cells). DSP cells cannot generate LSP cells since they are already in a more differentiated state.

Conclusion:

• Option 2 (A and C) is the correct answer because both A and C are true, which describes the behaviour of LSP cells as tumour-initiating stem cells that can differentiate into both LSP and DSP cells.

Information Booster:

1. LSP cells are typically cancer stem cells that can initiate tumours and can differentiate into more differentiated DSP cells.
2. DSP cells are generally more differentiated and do not have the ability to self-renew or initiate tumours.
3. Cancer stem cells (LSP cells) are essential for tumour initiation, self-renewal, and the formation of heterogeneous tumour populations.
4. LSP cells are capable of generating both LSP (stem-like) and DSP (differentiated) cells, which is consistent with their stem-like properties.