How do normal cells get transformed into cancerous neoplastic cells? Elaborate giving three examples of inducing agent.
Answer
Transformation of normal cells into cancerous neoplastic cells may be induced by following physical, chemical or biological agents causing DNA damage:
- Ionising radiations like X-rays and gamma rays
- Non-ionizing radiations like UV.
- Chemical carcinogens present in tobacco smoke
- Cellular oncogenes (c-onc) or proto-oncogenes, when activated under certain conditions cause cancer. Viruses with oncogenes can transform normal cells to cancerous cells.