The extreme elevations of markers for adenocarcinoma (CEA, CA19‐9), neuroendocrine tumours (NSE, ProGRP), squamous carcinoma (CYFRA, SCC), and hepato‐pancreato‐biliary cancer (PIVKA‐II, DUPAN‐2) naturally raised the differential diagnosis of synchronous primary cancers. This evidence concerns the gene ENO2 and squamous cell carcinoma.