Fig. 2

Indirect links between cancer and infections across human life. Green boxes and red boxes represent beneficial and detrimental links respectively. Childhood diseases and infection events occurring during the life of an individual could reduce cancer risk as they may enhance immune efficiency to eliminate cancer cells. In addition, some vaccines and treatments against infectious diseases have been reported to reduce cancer risk through the activation of anti-tumoral immunity. At the opposite end of the spectrum, infections may create inflammation or immunosuppression episodes that allow cancer cells to proliferate. Finally, chronic exposure to infections could account for age-related immune disorders and the inability to eliminate cancer cells