Which virus is classically associated with Kaposi sarcoma?

• A. EBV
• B. HPV
• C. HHV-8
• D. CMV

Answer: (C)

Kaposi sarcoma is driven by infection with a specific herpesvirus, human herpesvirus 8 (HHV-8), also called Kaposi sarcoma–associated herpesvirus. This virus is found in virtually all KS lesions and is considered a necessary factor for the tumor to develop, especially in the setting of immunosuppression. HHV-8 infects endothelial cells and expresses latency-associated proteins like LANA, which help the virus persist and promote angiogenic and proliferative processes. The result is the distinctive spindle-cell proliferation and abnormal blood vessel formation seen in KS lesions, often presenting as violaceous plaques or nodules.

EBV, HPV, and CMV cause other diseases (for example, EBV with certain lymphomas and nasopharyngeal carcinoma, HPV with cervical and other cancers, CMV with retinitis and systemic disease in immunocompromised individuals) and are not etiologic for Kaposi sarcoma. Therefore, the virus classically associated with Kaposi sarcoma is HHV-8.