The present invention relates to methods and compositions for the diagnostic and for the treatment of nasal intestinal type adenocarcinomas (ITAC). The inventors used a non-invasive brushing technique, which permits to identify transcriptomic and methylation modifications that are consistent with phenotypic profiles and ITACs natural history. Thus, they identified CACNA1C as a new predictive marker of ITAC. In particular, the invention relates to a method of determining whether a subject has or is at risk of having nasal intestinal type adenocarcinoma (ITAC) comprising determining the expression level of CACNA1C in a sample wherein said expression level indicates whether the subject has or is at risk of having a nasal intestinal type adenocarcinoma (ITAC)