In fact, one in six cancer cases worldwide is caused by a known infectious agent, with the proportion rising to one-third in some countries in Sub-Saharan Africa. The four main culprits are hepatitis B and C (hepB and hepC), human papillomavirus (HPV), and Helicobacter pylori, which are collectively responsible for 1.9 million cases of liver, cervical, and gastric cancer annually.