Kaposi's sarcoma herpesvirus or human herpesvirus-8 (KSHV/HHV-8) is the etiological agent of Kaposi's sarcoma (KS), an AIDS-defining angioproliferative neoplasm that continues to be a major global health problem and, of primary effusion lymphoma (PEL), a rare incurable B-cell lymphoma. This review describes the research from our laboratory and its collaborators to uncover molecular mechanisms of viral oncogenesis in order to develop new pathogenesis-based therapies to the KSHV-induced AIDS malignancies KS and PEL. They include the discovery of the viral angiogenic oncogene G protein-coupled receptor (vGPCR), the development of mouse models of KSHV and oxidative stress-induced KS, the identification of the role of Rac1-induced ROS in viral oncogenesis of KS and the development of novel therapeutic approaches able to target both latent and lytic oncogenic KSHV infection.