Tissue Biomarkers in Kaposi Sarcoma

Kaposi sarcoma is a vascular neoplasm arising from blood and lymphatic endothelial cells and is etiologically associated with Kaposi sarcoma–associated herpesvirus (KSHV/HHV-8). It is common in HIV-infected people, although it can also arise in non-HIV-infected patients. Histopathological examination remains the diagnostic gold standard; however, the morphological features of Kaposi sarcoma often overlap with those of other vascular tumors, creating diagnostic challenges. Tissue biomarkers play a crucial role in diagnosing Kaposi sarcoma. It can reveal the endothelial origin, the association with HHV-8 and the malignant origin of Kaposi sarcoma. This review summarizes several tissue biomarkers that were expressed in Kaposi sarcoma that can serve as diagnostic markers and molecular markers for Kaposi sarcoma.

LANA-1 (Latency-Associated Nuclear Antigen-1) is a protein that is characteristically expressed in Kaposi sarcoma. It was expressed in HHV-8 infected spindle cells of Kaposi sarcoma tissue. CD31 and CD34 biomarkers can confirm the vascular nature of spindle cells. D2-40 or podoplanin confirmed the lymphatic endothelial differentiation and supports the lymphatic phenotype of Kaposi sarcoma. Finally, Ki-67 biomarker is expressed in proliferating cells that can support the malignant behavior of Kaposi sarcoma. These biomarkers can confirm the diagnosis and support the molecular nature of Kaposi sarcoma.