How is the cell division of cancer cells like these misregulated? Select all that apply.

Such cells are not inhibited by density.
Such cells can divide in the absence of growth factors.
Such cells skip the G1 phase of the cell cycle.
Such cells do not require anchorage to a surface in order to divide.
Such cells do not respond to signals that normally trigger apoptosis.
Such cells do not need enzymes for DNA replication.

Cancer is due to irregularities in cell division that are caused by mutations in cancerous cells. These mutations inhibit apoptosis and favor cell division.  Among the options, the correct ones are 1, 2, 4, and 5.

Cancer is the result of irregular cell division.

Its development and progression are closely related to changes in the cell cycle regulator factors.

Cancerous cells

•Divide when they should not do it  ⇒ overactivity of the positive cell division regulators.

•Do not stop dividing when they should  ⇒ reduction in the activity of cell division inhibitors

•Do not die when they should  ⇒ loss of the apoptotic capability

•Leave the area where they are growing ad travel to other parts of the body ⇒ metastasis

Normal cells divide and die during a programmed period.

When a normal cell mutates or suffers from any alterations that can not be repaired, it automatically activates its apoptotic process.

However, cancerous cells lose the capability of dying and their reproductive inhibition, so they keep growing and dividing with no limits.

The unlimited division occurs because mutations in cancerous cells influence the cell cycle by favoring proliferation and inhibiting senescence and apoptosis.

These cells do not depend on external growth factors or other protein signals to divide.

Cancerous cells can release their own growth factor and even influence neighbor cells to produce and release these substances.

Cell division is constant even when there is no space.

Sometimes over multiplication creates tumors that might affect healthy neighbor cells and the tissue itself.

Among the options,

1) Such cells are not inhibited by density. CORRECT

2) Such cells can divide in the absence of growth factors. CORRECT

3) Such cells skip the G1 phase of the cell cycle. INCORRECT

4) Such cells do not require anchorage to a surface in order to divide. CORRECT

5) Such cells do not respond to signals that normally trigger apoptosis. CORRECT

6) Such cells do not need enzymes for DNA replication. INCORRECT

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Cancer cells can divide in the absence of growth factors.  Cancer cells do not require anchorage to a surface in order to divide.  Cancer cells do not respond to signals that normally trigger apoptosis.

Cancer cells can multiply without any growth factors whereas normal cells will not divide without the addition of growth factors. Cancer and tumor cells are less dependent on anchorage. They are free to proliferate, and invade tissues. A normal cell that have damaged DNA will undergo apoptosis while on the other hand, cancer cell with unfixable DNA will not undergo apoptosis and will continue multiplication.

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