Assoc. Professor Zajac Vladimír, PhD. graduated from Comenius University (Bratislava, Slovakia) in 1973 and ever since has been working at the Cancer Research Institute, SAS (Bratislava), where he obtained his PhD degree in 1981, since then. He joined the Medical Faculty of the Comenius University as Associate Professor in Genetics in 2007. Dr. Zajac began working with bovine leukemia virus (BLV) in 1976., and has been engaged in the study of the role of bacteria in bovine leukosis and AIDS since 1990. The fundamental study was done in Prof. F. Wong-Staal’s laboratory (UCSD, San Diego). Since 1994, Dr. Zajac’s research is focused on hereditary forms of colon, breast and ovarian cancer. His cancer genetics study culminated in Prof. A. P. Monaco’s laboratory (University of Oxford). His particular interest and life-long scientific work concerns the study of horizontal transfer of genetic information between eukaryotic and prokaryotic systems, with focus on retroviruses and the consequences of transmission in induction of cancer and AIDS.