Thus, K13 activity may contribute to neoangiogenesis in KS lesions via increased production of angiogenic factors, such as IL-8, SEMA3C and TNFAIP2, and to invasion and metastases by stimulating extracellular matrix remodeling through increased production of MMP10 and TNFAIP6. The gene discussed is TNFAIP2; the disease is Kaposi's sarcoma.