As a model system, we examined CCND1 and HER-2/neu oncogenes in normal mucus and tumoral tissue of both the esophagus and stomach by using a FISH assay, since these genes have been shown to become amplified and/or over-expressed in these two types of tumor (Takehana et al., 2002; Shiomi et al., 2003; Dahlberg et al., 2004; Manoel-Caetano et al., 2004). This evidence concerns the gene ERBB2 and neoplasm.