HOXA5 and nasopharyngeal carcinoma: HOXA5, 2, and 6 are methylation targets associated with the progression of many cancers; for example, increased methylation in the HOXA5 promoter region is associated with its decreased expression during skin tumor progression (24), and aberrantly hypermethylated HOXA2 represses metalloproteinase-9 through TBP and promotes invasion in nasopharyngeal carcinoma (25).