Read the following passage carefully and answer the given questions.
Cancerous cells just continue to divide giving rise to masses of cells called tumors. Benign tumors normally remain confined to their original location and do not spread to other parts of the body and cause little damage. The malignant tumors, on the other hand are a mass of proliferating cells called neoplastic or tumor cells. Transformation of normal cells into cancerous neoplastic cells may be induced by physical, chemical or biological agents. Ionising radiations like X-rays and gamma rays and non-ionizing radiations like UV cause cancer. Cancer-causing viruses are called oncogenic viruses which have viral oncogenes. The substances to which an immune response is produced are called allergens. The antibodies produced to these are of IgE type. Common examples of allergens are mites in dust, pollens, animal dander, etc. The primary lymphoid organs are bone marrow and thymus. The secondary lymphoid organs provide the sites for interaction of lymphocytes with the antigen, which then proliferate to become effector cells.
Which one of the following cannot cause cancer?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Physical contact with the cancer patient
Agents that change normal cells into cancerous (neoplastic) cells are called carcinogens. They are of three kinds: physical, chemical and biological.
Option (1) Chemicals present in tobacco — Can cause cancer. These are chemical carcinogens. The chemicals in tobacco smoke are a major cause of lung cancer.
Option (2) Oncogenic viruses — Can cause cancer. These are biological carcinogens. Cancer-causing viruses carry genes called viral oncogenes, which can turn a normal cell into a cancer cell.
Option (3) Physical contact with the cancer patient — Cannot cause cancer. Cancer is not an infectious disease. It starts when the control of cell division breaks down inside a person’s own cells. Touching or caring for a patient does not change anyone else’s cells. The word “physical” in the passage means physical agents such as radiation, not touch.
Option (4) Ionizing radiation like X-rays and gamma rays — Can cause cancer. These are physical carcinogens. Ionising radiation, and also non-ionising UV radiation, damages DNA and leads to neoplastic transformation.
Note: The passage is taken from NCERT. NTA has put lines of the NCERT text together to make it. Most CUET (UG) questions come straight from NCERT, so study the book line by line, including figures and their titles.