Final answer:
Changes in apoptosis, DNA repair, and cell cycle regulation are often observed in cancer cells that continue to divide despite being defective, leading to uncontrolled cell growth and tumor development.
Step-by-step explanation:
Cancer cells that continue to divide even when defective often exhibit changes in several cellular functions; these include apoptosis (also known as programmed cell death), DNA repair mechanisms, and cell cycle regulation. When these functions are altered, cells can proliferate uncontrollably, potentially leading to tumor formation. Apoptosis is a vital process that eliminates faulty or damaged cells, preventing them from becoming cancerous.
However, cancer cells may evade apoptosis due to mutations that interfere with apoptosis signaling, the loss of receptors for apoptosis-inducing ligands, or the overexpression of growth factor pathways that inhibit apoptosis. The DNA repair ability of a cell is essential for maintaining genomic integrity, and defects in this system can increase mutation rates, contributing to cancer progression. Moreover, mutations affecting proteins that regulate the cell cycle, such as tumor suppressor genes or cyclins, can result in uncontrolled cell division, a hallmark of cancerous growth.