PTGS1 and nasopharyngeal carcinoma: In this context, it is interesting to note that PTGS1 methylation is frequent in prostate cancer (Bastian et al, 2005), THY1 has been implicated as a candidate TSG in nasopharyngeal cancer (Lung et al, 2005) and SST promoter methylation has been described in ∼90% of colorectal cancers (Mori et al, 2006).