Which of the following statements best supports the hypothesis that viruses can cause cancer?
A.
Cancerous and normal cells share genetic sequences.
B.
Cellular DNA has sequences related to viral sequences.
C.
Viruses and cancer cells both replicate rapidly.
D.
Genes that regulate cell division are found in some viruses.
The Correct Answer and Explanation is:
The correct answer is:
D. Genes that regulate cell division are found in some viruses.
Explanation:
Viruses have long been linked to certain types of cancer, primarily due to their ability to interfere with the normal regulatory processes of cells, particularly those that control cell division. The statement that “genes that regulate cell division are found in some viruses” directly supports the hypothesis that viruses can cause cancer because it suggests that viral genetic material can manipulate or disrupt the mechanisms that control cell growth and replication.
Cancer occurs when normal cells transform into malignant cells through a process called oncogenesis. In healthy cells, the regulation of cell division is controlled by a balance of proto-oncogenes, which promote cell division, and tumor suppressor genes, which inhibit uncontrolled growth. If a virus introduces genes that either activate proto-oncogenes or disable tumor suppressor genes, it can lead to unchecked cell proliferation, a hallmark of cancer. For example, some viruses like the human papillomavirus (HPV) carry oncogenes that disrupt tumor suppressor pathways, leading to cervical and other cancers.
The idea that viruses can cause cancer is supported by well-documented cases in which specific viruses are linked to certain cancers. For example, the Epstein-Barr virus (EBV) is associated with Burkitt’s lymphoma, and hepatitis B and C viruses are linked to liver cancer. HPV is the best-known example of a virus that directly causes cancer by interfering with the normal regulation of cell division.
The other answer choices are less directly related to how viruses cause cancer. For instance, while viruses and cancer cells both replicate rapidly, this is a general similarity and does not explain how viruses can induce cancer. Therefore, option D most clearly supports the hypothesis that viruses can lead to cancer formation.