Question

What can promote tumor formation by non-mutational mechanisms?

Answer 1

Formation of tumors by non-mutational mechanisms:

1. Infection by oncogenic viruses and chronic tissue injuries mainly facilitates the formation of tumors by non-mutational mechanisms.
2. Human Papillomavirus: Anal Carcinoma, Penile Carcinoma, Cervical Carcinoma.
3. Epstein Barr Virus: Burkitt's Lymphoma, Nasopharyngeal Carcinoma.
4. Merkel Cell Polyoma: Merkel Cell Carcinoma.
5. Hepatitis Virus B or C: Hepatocellular carcinoma.
6. Human Adult T cell Leukemia Virus: T cell leukemia.
7. All these viral infections produce oncogenic proteins which alter the activities of tumor suppressor genes like p53.
8. It's also achieved by inactivating the retinoblastoma protein, cleaving the transcriptional factor E2F to bypass G1/S phase checkpoints.
9. Persistent irritation, caused by long-term exposure of lung cells to asbestos fibres or tobacco smoke particles, promotes inflammatory and proliferative responses.
10. The chemicals produced in these inflammatory responses often cause DNA damage more than Hayflick's limit and the cell simply bypasses the step for apoptosis and causes cancer.