infection correlates with two types of microsatellite alterations in colorectal cancer and triggers DNA damage.

() is frequently found in colorectal cancers (CRCs). High loads of DNA are detected in CRC tissues with microsatellite instability-high (MSI-H), or with the island hypermethylation phenotype (CIMP). infection is also associated with the inflammatory tumor microenvironment of CRC. A subtype of CRC exhibits inflammation-associated microsatellite alterations (IAMA), which are characterized by microsatellite instability-low (MSI-L) and/or an elevated level of microsatellite alterations at selected tetra-nucleotide repeats (EMAST). Here we describe two independent CRC cohorts in which heavy or moderate loads of DNA are associated with MSI-H and L/E CRC respectively. We also show evidence that produces factors that induce γ-H2AX, a hallmark of DNA double strand breaks (DSBs), in the infected cells.