After graduating from medical school at the Katholieke Universiteit Leuven, Belgium, Prof. Janssens combined specialization in radiotherapy & oncology with molecular biology. He received various scholarships in the Health Science Center of the University of Texas at San Antonio, the Baylor College in Houston, the MD Anderson Cancer Institute at Houston, the Roger Adams Institute at Champaign, University of Illinois, US and Henri Mondor Hospital in Paris. His main clinical work is at the Limburg Oncological Center in Belgium, primarily in the field of gynaecological oncology. His research interests are mainly about breast cancer molecular biology and lifestyle factors in children related to breast cancer. Since 2004, he has been the president of the European Cancer Prevention Organization, the editor of the European Journal of Cancer Prevention, the author of about 200 Peer-reviewed publications mainly in the field of breast cancer and the owner of 5 medical products and devices related patents.