B2M, which encodes the small chain of the MHC I molecule crucial for MHC I assembly, was expressed at lower levels in colon cancer cell lines relative to normal colon (Fig 1A, Fig 2A, S1A Fig) However, 3/8 colon cancer cell lines significantly upregulated B2M after treatment with low doses of 5-AC (Fig 1A). This evidence concerns the gene B2M and colonic neoplasm.