What is the primary difference between normal cells and cancer cells?

Cancer cells are characterized by their uncontrolled growth and reproduction. This is primarily evidenced by their ability to continue dividing and proliferating even when they become densely packed together. In contrast, normal cells typically stop dividing when they reach a certain density due to a process known as contact inhibition, which helps regulate cell growth and prevent overcrowding.

In the context of cancer biology, this loss of contact inhibition allows cancer cells to form tumors, invade surrounding tissues, and metastasize to other parts of the body. The abnormal growth of cancer cells is a central factor in the development and progression of cancer, distinguishing them from normal cells that maintain regulatory mechanisms governing their proliferation.

Understanding this feature of cancer cells is crucial in the study of cancer biology and in developing targeted therapies that aim to restore the normal regulatory processes that are lost in cancerous cells.