A cancer-causing agent is any substance, radionuclide, or radiation that advances carcinogenesis, the development of malignant growth. This might be because of the capacity to harm the genome or to the disturbance of cell metabolic cycles. A few radioactive substances are viewed as cancer-causing agents, however their cancer-causing movement is credited to the radiation, for instance gamma beams and alpha particles, which they produce. Normal instances of non-radioactive cancer-causing agents are breathed in asbestos, certain dioxins, and tobacco smoke. Albeit the general population for the most part connects cancer-causing nature with manufactured synthetic substances, it is similarly prone to emerge in both regular and engineered substances. Carcinogens are not really quickly poisonous; in this manner, their impact can be guileful.

Malignancy is any infection where ordinary cells are harmed and don't go through customized cell passing as quick as they partition by means of mitosis. Cancer-causing agents may build the danger of disease by changing cell digestion or harming DNA straightforwardly in cells, which meddles with organic cycles, and instigates the uncontrolled, dangerous division, at last prompting the development of tumors. Generally, serious DNA harm prompts modified cell demise, however in the event that the customized cell passing pathway is harmed, the cell can't keep itself from turning into a malignancy cell.

There are numerous regular cancer-causing agents. Aflatoxin B1, which is delivered by the organism Aspergillus flavus developing on put away grains, nuts and peanut butter, is an illustration of a strong, normally happening microbial cancer-causing agent. Certain infections like hepatitis B and human papilloma infection have been found to cause malignant growth in people. The first one displayed to cause malignancy in quite a while is Rous sarcoma infection, found in 1910 by Peyton Rous. Other irresistible organic entities which cause disease in people incorporate a few microbes (for example Helicobacter pylori  and helminths (for example Opisthorchis viverrini  and Clonorchis sinensis).

Dioxins and dioxin-like mixtures, benzene, kepone, EDB, and asbestos have all been named carcinogenic. As far back as the 1930s, Industrial smoke and tobacco smoke were distinguished as wellsprings of many cancer-causing agents, including benzo[a]pyrene, tobacco-explicit nitrosamines, for example, nitrosonornicotine, and responsive aldehydes like formaldehyde, which is likewise a danger in treating and making plastics. Vinyl chloride, from which PVC is fabricated, is a cancer-causing agent and consequently a danger in PVC creation.

Co-cancer-causing agents are synthetic substances that don't really cause malignant growth all alone, yet advance the action of different cancer-causing agents in causing disease.

After the cancer-causing agent enters the body, the body makes an endeavor to kill it through an interaction called biotransformation. The reason for these responses is to make the cancer-causing agent more water-solvent with the goal that it tends to be taken out from the body. Notwithstanding, now and again, these responses can likewise change over a less poisonous cancer-causing agent into a more harmful cancer-causing agent.

DNA is nucleophilic; hence, dissolvable carbon electrophiles are cancer-causing, since DNA assaults them. For instance, a few alkenes are toxicated by human compounds to create an electrophilic epoxide. DNA assaults the epoxide, and is bound forever to it. This is the component behind the cancer-causing nature of benzo pyrene in tobacco smoke, other aromatics, aflatoxin and mustard gas.