Final answer:
The cycle of cancer refers to the unchecked cell division caused by a breakdown of the mechanisms that regulate the cell cycle. Faulty instructions in the DNA sequence result in the formation of a tumor as rapidly reproducing cancer cells crowd out normal cells and cause harm to tissues and organs.
Step-by-step explanation:
The cycle of cancer refers to the result of unchecked cell division caused by a breakdown of the mechanisms that regulate the cell cycle. This loss of control begins with a change in the DNA sequence of a gene that codes for one of the regulatory molecules, leading to faulty instructions and a protein that does not function properly. As a result, each successive cell division gives rise to daughter cells with accumulated damage, which eventually leads to the formation of a tumor. Rapidly reproducing cancer cells crowd out normal cells, causing harm to tissues and organs.