A common polymorphism - a variation in a person's DNA sequence that is found with regularity in the general population - can lead to a chain of events that dictates how a tumor will progress in certain types of cancer, including a form of breast cancer, as well as ovarian cancer, according to new research from The Wistar Institute in Philadelphia, Pennsylvania, that was published online by the journal Cancer Cell. The research reveals a more explicit role about the symbiotic relationship humans have with the various bacteria that inhabit our body and their role during tumor progression. "Our research indicates that interactions between the helpful bacteria in our bodies and immune cells at places situated away from tumors influence systemic responses in the host that alter how these tumors are able to progress," said José Conejo-Garcia, M.D., Ph.D., Associate Professor and Program Leader in the Tumor Microenvironment and Metastasis Program at The Wistar Institute and lead author of the study. Humans are colonized with trillions of bacteria - known as commensal bacteria because there are benefits to having these bacteria in our bodies - that inhabit the gastrointestinal and respiratory tracts and our skin. These bacteria provide a first line of defense against infection. Recent research has found that interactions between these bacteria and the immune system are critical for providing important defenses against tumors occurring outside of the intestines. In order for the immune system to recognize commensal, as well as microscopic organisms that can cause disease - or pathogens - many of our cells are programmed to recognize pathogen-associated molecular patterns.Login Or Register To Read Full Story