What is the major cause of lung cancer identified?

Step-by-step solution

Malignant tumors are a mass of proliferating cells that grow rapidly, invading and damaging the surrounding normal tissues.Both ionizing radiations such as X-rays and gamma rays, as well as non-ionizing radiations such as UV, cause DNA damage leading to neoplastic transformation. The chemical carcinogens present in tobacco smoke have been identified as a major cause of lung cancer . Several genes called cellular oncogenes or proto oncogenes have been identified in normal cells which, when activated under certain co