- A Carcinogens are substances that are understood by oncologists to actively cure and largely eliminate existing tumours in patients, shrinking malignant growths within days of a patient's first exposure to the substance
- B Agents that cause cancer by inducing DNA mutations or epigenetic changes: tobacco smoke (PAHs, nitrosamines), UV radiation (causes C→T mutations in skin), aflatoxin B1 (liver cancer from mouldy peanuts)
- C Carcinogens are understood to consist mainly of various forms of high-energy ionizing radiation exposure alone, with little chemical compounds such as tobacco smoke or aflatoxins ever classified as carcinogenic
- D Carcinogens are understood to specifically and mainly ever cause cancer development within lung tissue, nowhere else, rarely being implicated in skin, liver, bladder, or any other organ's cancer development
Correct answer: B. Agents that cause cancer by inducing DNA mutations or epigenetic changes: tobacco smoke (PAHs, nitrosamines), UV radiation (causes C→T mutations in skin), aflatoxin B1 (liver cancer from mouldy peanuts)
Explanation: Carcinogens cause cancer by: (1) Direct DNA damage/mutation (genotoxic); (2) Promoting cell proliferation (mitogenic). Examples: (1) Tobacco - most preventable cancer cause; (2) UV radiation - melanoma, BCC, SCC; (3) Aflatoxin B1 (Aspergillus flavus) - hepatocellular carcinoma; (4) H. pylori - stomach cancer; (5) HPV - cervical cancer; (6) Benzene - leukaemia.
Concept context
Pathogens, infectious diseases, non-infectious diseases, drugs, cancer, and public health. High NEET importance.