The amount of Fn DNA in fresh-frozen CRC tissue was associated with proximal tumor location (p = 0.001), higher depth of invasion (p = 0.035), poorly differentiated tumors (p = 0.011), MSI-positive (p < 0.0001), BRAF mutated tumors (p < 0.0001), and with the loss of expression of mismatch-repair proteins MLH1 (p < 0.0001), MSH2 (p = 0.003), and PMS2 (p < 0.0001). The gene discussed is MSH2; the disease is colorectal carcinoma.