What is the role of viruses in cancer?

Retroviruses are viruses that splice their genes into the DNA of their hosts in an attempt to make the host copy their genes. If this splicing occurs in specific locations, it can disrupt the host cell's replication machinery and potentially cause unchecked cell division.

Unchecked cell division has the potential to cause tumor growth.

This is a very basic overview; please let me know if you would like a more thorough explanation.

Certain viruses can cause cancer by interfering with the cell's regulatory mechanisms or by inducing chronic inflammation, which can increase the risk of cancer development. Viruses can also cause cancer by inserting their genetic material into the DNA of the host cell, which can result in mutations that disrupt normal cellular processes and potentially trigger cancerous growth.