To identify molecular markers that distinguish colon and ovarian adenocarcinomas, we developed a multistep "omic" procedure using cDNA microarrays, clone sequencing, synthetic oligonucleotide chips, and "reverse-phase" protein microarrays. The two candidate markers (villin and moesin) that emerged from this process were then validated in tissue microarrays that included 91 colon and 42 ovarian clinical tumors. The two markers proved comparable in diagnostic power to the current standard markers cytokeratins 7 and 20. Multistep omic protocols such as the one presented here have the potential for discovery of additional markers for cancer diagnosis, prognosis, and therapy. For details, see the article by Nishizuka et al. on p. 5243 of this issue.