Question

Which of the following mechanisms are found to result in cancer caused by viruses?

a.) The virus carries genes that can cause the cancer
b.) Viruses carry genes from an existing tumor to other ody sited to cause cancer.
c.) Viral proteins cause changes in growth regulation, leading to cancer.
d.) Bacteriophage from host microbiota infect host cells to cause cancer.

Answer 1

Viruses cause cancer by carrying oncogenes or by interfering with cell growth regulation, leading to uncontrolled proliferation. Examples include HPV and hepatitis B virus. Bacteriophages infect bacteria and are not directly linked to cancer in humans.

Step-by-step explanation:

Mechanisms through which viruses can cause cancer include:

• The virus carrying genes that directly cause cancer. These oncogenes stimulate unregulated cell growth.
• Viral proteins that interfere with growth regulation, altering the cell cycle and leading to cancer.

Some examples of oncogenic viruses are the Human Papilloma Virus (HPV), which is associated with cervical cancer, and the hepatitis B virus, linked to liver cancer. Acutely-transforming viruses carry viral oncogenes and transform cells as soon as these are expressed. Slowly-transforming viruses may later result in cancer by inserting their genome near a host cell's proto-oncogene, leading to its overexpression and causing uncontrolled cell proliferation.

Bacteriophages, which are viruses that infect bacteria, do not directly cause cancer in humans; they just infect bacterial cells.