Virus causing oropharyngeal carcinoma ?
**Core Concept**
Human papillomavirus (HPV) is a significant risk factor for oropharyngeal squamous cell carcinoma (OPSCC), a type of head and neck cancer. HPV is a DNA virus that primarily infects epithelial cells, leading to uncontrolled cell growth and cancer.
**Why the Correct Answer is Right**
HPV, particularly high-risk types such as HPV-16 and HPV-18, is associated with the development of OPSCC. This is due to the virus's ability to integrate into the host genome and express oncogenes that promote cell proliferation and inhibit apoptosis. The E6 and E7 proteins of HPV-16 and HPV-18, respectively, are key oncogenic proteins that contribute to carcinogenesis. The presence of HPV DNA in tumor tissue is a prognostic marker for improved survival and response to treatment.
**Why Each Wrong Option is Incorrect**
**Option A:** Epstein-Barr virus (EBV) is primarily associated with nasopharyngeal carcinoma, not oropharyngeal carcinoma.
**Option B:** Human immunodeficiency virus (HIV) increases the risk of various cancers, including Kaposi's sarcoma and non-Hodgkin lymphoma, but is not directly linked to oropharyngeal carcinoma.
**Option C:** Cigarette smoking is a major risk factor for head and neck cancers, including oropharyngeal carcinoma, but it is not the causative agent.
**Clinical Pearl / High-Yield Fact**
HPV vaccination is effective in preventing oropharyngeal carcinoma and is recommended for individuals at high risk, such as those with a history of smoking or sexual transmission.
**Correct Answer:** D.