Molecular events that lead to recurrence and/or metastasis after curative treatment of patients with colorectal cancers (CRCs) are poorly understood. Patients with stage II or III primary CRC with increased numbers of microsatellite alterations at selected tetra-nucleotide repeats (EMAST) and low levels of microsatellite instability (E/L) are more likely to have disease recurrence after treatment. Hypoxia and/or inflammation not only promote metastasis but also induce EMAST by causing deficiency of MSH3 in the cancer cell nucleus.