Final answer:
Cancerous tumors are heterogeneous due to ongoing mutations and environmental influences within the tumor microenvironment, leading to a diversity of cancer cell profiles within a monoclonal tumor origin. The lack of cell cycle control allows these cells to divide uncontrollably and potentially spread to other parts of the body via metastasis.
Step-by-step explanation:
While cancers are indeed monoclonal, meaning they originate from a single mutated cell, the tumors they form are surprisingly heterogeneous. This heterogeneity arises from several factors. First and foremost, as a cancerous tumor grows, the cells within it accumulate additional DNA mutations at a rapid rate. This process creates a diverse population of cancer cells with slightly different genetic profiles, leading to variability in behavior and characteristics within the tumor. Secondly, the tumor microenvironment, which includes surrounding blood vessels, immune cells, and the extracellular matrix, can influence cancer cell diversity through signals that promote further mutations or select for certain cell types. This continuous evolutionary process within the tumor contributes to the development of resistance to therapies and the ability of some cells to metastasize.
Cancer Cell Cycle Loss of Control: Cancer involves a loss of the ability of cells to control their cell cycle, consequently leading to cells that divide uncontrollably. Over time, this results in a mass of cells, known as a tumor, which can be benign or malignant. Malignant tumors are cancerous and lack growth limitations, hence can invade neighboring tissues and spread throughout the body in the process of metastasis.