your answer MATE::--Causes of Cancer:-• Transformation of normal cells to neoplastic cells is due carcinogen. Carcinogen is physical, chemical, or biological agent responsible for transformation. Examples of carcinogens are:• X-RAYS, gamma rays, non-ionising radiations like UV cause DNA damage, tobacco smoke (lung cancer), Alcohol (liver cancer),•Cadmium--Bone Cancer, Arsenic--Skin Cancer, Lead--Kidney Cancer, Copper--Wilm's Tumour of the Kidney• HIV -- Kaposi's SARCOMA, Hepatitis B Virus (Liver Cancer), Human PAPILLOMA virus (Cervical cancer), Epstein Barr Virus and Cytomegalovirus -- nasopharyngeal cancer, Schistosoma haematobium -- Urinary bladder cancer•Cancer inducing viruses are called Oncogenic viruses. These viruses carry genes called viral oncogenes. Several genes called cellular oncogenes (c-onc) or proto oncogenes are identified in normal cells which upon activation by carcinogen lead to oncogenic transformation.• Proto oncogene ----> Oncogene ----> Transformation of normal cell ----> Neoplastic cell ----> Tumour