Human papillomavirus (HPV) ?is very common in males and ternales. Although most infections are cleared within a few weeks, there are to HPV types than have severe long term effects and are responsible for 70% ?of all cervical cancers. How can some viruses be related to cancer?O The virus forces the cells to produce more viruses and this always results in cancer The virus lyses the cell as it exists the cells and this makes the cell become cancerous
The Correct Answer and Explanation is :
The correct answer is: Some viruses can cause cancer by integrating their DNA into the host cell’s genome, which disrupts normal cellular function and can lead to uncontrolled cell division.
Explanation:
Viruses like certain types of human papillomavirus (HPV) are linked to cancer because they interfere with the normal regulation of the cell cycle. High-risk HPV types, particularly HPV 16 and HPV 18, are responsible for about 70% of cervical cancer cases. These viruses carry genes (e.g., E6 and E7) that produce proteins capable of inactivating tumor suppressor proteins in human cells.
- Integration of Viral DNA:
High-risk HPVs integrate their DNA into the host cell’s genome. This alters the host cell’s normal genetic regulation and can activate oncogenes or silence tumor suppressor genes. - Inactivation of Tumor Suppressors:
- The E6 protein binds to and degrades p53, a key tumor suppressor protein responsible for initiating DNA repair or apoptosis (programmed cell death) when cellular damage occurs. Without functional p53, the cell cannot effectively prevent the accumulation of mutations.
- The E7 protein binds to retinoblastoma protein (Rb), another tumor suppressor. Rb normally controls cell cycle progression. When Rb is inactivated, cells divide uncontrollably.
- Uncontrolled Cell Growth:
These disruptions allow infected cells to bypass normal growth controls, leading to uncontrolled proliferation and, eventually, the accumulation of further mutations that can transform a normal cell into a cancerous one. - Chronic Inflammation:
Persistent infection with high-risk HPV strains can also cause chronic inflammation, which increases oxidative stress and DNA damage, further contributing to carcinogenesis.
While most HPV infections are cleared naturally by the immune system within weeks to months, persistent infections with high-risk types can lead to precancerous lesions and, over time, invasive cancer if not detected and treated early. Vaccination and regular screenings (e.g., Pap smears) are key in preventing HPV-related cancers.