Perspectives on microbes as oncogenic infectious agents and implications for breast cancer.

Cancer management is partly based on weighing risk factors attributed to noninfectious agents, human genes and epigenetic factors. Infectious disease causation has largely been restricted to genes directly responsible for causing cancer after sustaining damage i.e. oncogenes. Lately, evidence has emerged linking infectious agents to a number of chronic diseases. These studies have recognized the influence that acute, atypical, latent and chronic infections may play in tricking the immune system and affecting disease etiology. Similar evidence is emerging in model systems with respect to the role of infectious agents in gastrointestinal, liver and lung cancers. Although viruses have been found in association with breast cancer, skepticism remains about a role for other infectious agents, notably microbes in the disease etiology. Improved experimental designs employed in different cancer studies and a less rigid definition of infectious causation may aid in confirming or refuting a microbe-breast cancer connection. Cancer recurrence could potentially be minimized and treatment options further tailored on a case by case basis if microbes/microbial components/strain variants associated with breast cancer are identified; probiotics are employed to reduce treatment side-effects and if microbes could effectively be harnessed in immunotherapy.