SMAD4 and carcinoma of esophagus: This in disagreement with several studies that revealed that hypermethylation was not found in colorectal malignancies and small intestinal neuroendocrine tumors [45–47], but our results were in agreement with study by Onwuegbusi et al. who reported that 70% of esophageal carcinoma cases were found to be hypermethylated at SMAD4 promoter [48].