Question

which of the following characteristics is associated with cancer cells?
they must be attached to a substrate to divide in culture.
they evade the normal controls that trigger programmed cell death.
they exhibit density - dependent inhibition when growing in culture.
they stop dividing in culture when growth factors are depleted.

Explanation:

Cancer cells have the ability to evade apoptosis (programmed cell death). Normal cells undergo apoptosis when there are certain signals (like DNA damage), but cancer cells can avoid this process.

• Normal cells (not cancer cells) need to be attached to a substrate (anchorage dependence) to divide in culture. Cancer cells can sometimes be less dependent on this.
• Normal cells exhibit density - dependent inhibition (stop growing when they reach a certain cell density), while cancer cells do not.
• Normal cells stop dividing when growth factors are depleted. Cancer cells may have mechanisms (like autocrine growth factor production) to continue growing even with limited external growth factors.

Answer:

They evade the normal controls that trigger programmed cell death.