Final answer:
Cancer interrupts the cell cycle due to body cells losing the ability to control growth. It results from mutations in regulatory genes, often caused by environmental factors or inherited genetic abnormalities. This leads to uncontrolled cell division and tumor formation.
Step-by-step explanation:
Cancer is considered a disruption of the cell cycle because body cells lose the ability to control growth. This breakdown in regulation is due to a change in the DNA sequence of genes that code for regulatory molecules of the cell cycle. A single faulty instruction can lead to a protein that does not function properly, allowing for a cascade of errors that can be passed down to daughter cells with each division, resulting in more damage. Cancerous cells divide much faster than normal cells, often leading to tumorous growth that can crowd out normal cells, thus damaging tissues and organs.
Cancer occurs due to mutations in the genes that control the cell cycle. These mutations can be a result of environmental factors such as exposure to radiation or toxic chemicals, or they can be due to inherited genetic abnormalities. The lack of control in cell division allows cancer to develop, sometimes manifesting as tumors or, in the case of leukemia, abnormal blood cell production without the presence of a solid tumor.