Final answer:
Integration and upregulation of viral oncogenes occur at the stage of high-risk HPV infection, which can lead to cervical cancer.
Step-by-step explanation:
Integration and upregulation of viral oncogenes in HPV progression occur at the stage of high-risk infection.
When the high-risk types of HPV enter a cell, two viral proteins are used to neutralize proteins that the host cells use as checkpoints in the cell cycle. These proteins, including E6, bind to p53, impairing its function. As a result, the cell remains in a state of fast growth, allowing mutations to accumulate in its DNA.
High-risk HPV strains, such as HPV 16 or HPV 18, can cause cervical cancer and are responsible for more than 70 percent of all cervical cancer diagnoses. If the HPV infection persists, it can influence the cells of the cervix to develop precancerous changes.