Kaposi Sarcoma-Associated Herpesvirus Is Not Detected in Osteosarcoma From KSHV-Endemic African Countries and the Non-Endemic United States Populations.

Osteosarcoma is an aggressive primary malignant bone tumor of poorly defined etiology that predominantly affects adolescents and young adults. A viral cause has long been proposed, and a recent study from Xinjiang, China, reported frequent detection of Kaposi sarcoma-associated herpesvirus (KSHV) in Uyghur osteosarcoma cases, suggesting a possible association in this KSHV-endemic population. Whether this association extends to broader populations remains unknown. Our study investigated the presence of KSHV in osteosarcoma specimens from KSHV-endemic African countries (Cameroon, Kenya, South Africa, Zambia) and the non-endemic United States. A total of 356 formalin-fixed paraffin-embedded and fresh-frozen specimens were retrieved or prospectively collected. In 77 selected high-quality specimens, KSHV infection was assessed by immunohistochemistry for LANA1 and by qPCR targeting 5 viral open reading frames (ORF25, ORF26, ORF37, ORF65, and ORF73). LANA1 expression was undetectable in all tumors. Using qPCR, 75/77 specimens were negative for all targets, 1/77 excluded due to insufficient remaining DNA quantity to perform the assay, and 1/77 positive across all five targets. Additionally, we studied the KSHV seroprevalence in a separate cohort comprised of 49 sera obtained from individuals with osteosarcoma from Zambia (n = 39) and the United States (n = 10). We measured by ELISA the presence of specific antibodies against four KSHV antigens: K8.1, KCP, VCA, and LANA1. KSHV seropositivity was detected in 15/39 individuals from Zambia and none from the United States. In the absence of compelling evidence, our findings could not support an association between KSHV infection and osteosarcoma in our study population.