Final answer:
Successive mutations in tumor development lead to uncontrolled growth and amplification of tumorigenic cells, characterized by unchecked growth, evasion of apoptosis, limitless replicative potential, and the possibility of metastasis.
Step-by-step explanation:
In tumor development, successive mutations further increase the rate of cell division, resulting in uncontrolled growth and amplification of tumorigenic cells. This process involves the transformation of normal cells into cancerous ones through a series of steps beginning with the initiation stage, where the right genes mutate, so the cell avoids death and begins abnormal proliferation. As the cells divide, they accumulate more mutations, which may lead to the inactivation of DNA repair genes or conversion of proto-oncogenes into oncogenes, causing further unchecked growth. Some mutations result in the loss of sensitivity to anti-growth signals, evasion of programmed cell death (apoptosis), and potential for limitless division, leading to the characteristic limitless replicative potential or 'immortality' of cancer cells. Additionally, the acquisition of sustained angiogenesis supports the tumor's growth beyond the limitations of passive nutrient diffusion, further contributing to cancer development. Although many tumors are benign, those that become malignant can metastasize, forming tumors in other organs. Overall, cancer development is a complex process marked by the accumulation of genetic damage in both proto-oncogenes and tumor-suppressor genes.