Final answer:
Reactivation of oncogenes can lead to increased cell division and growth, disrupting the regulation of the cell cycle and potentially resulting in the development of cancerous cells.
Step-by-step explanation:
If oncogenes are reactivated during growth and development, the result is typically increased cell division and growth, as well as the potential development of cancerous cells. Oncogenes are mutated forms of proto-oncogenes, which normally play a role in cell growth and division. When these genetic elements are altered, they can lead to the overproduction or overactivity of growth-promoting proteins. This can disrupt the delicate balance of cell regulation, allowing uncontrolled cell proliferation which might eventually result in the formation of tumors. Such abnormalities can arise from various factors including genetic predisposition, environmental factors, or exposure to carcinogens.
Cancer occurs when the mechanisms regulating the cell cycle are compromised, leading to unchecked division of cells. Tumor-suppressor genes are also essential in this balance; they normally work to prevent the uncontrolled growth of cells. When both the activity of oncogenes increases and the function of tumor-suppressor genes decreases due to mutations, this can lead to cancer.