SMAD4 and malignant colon neoplasm: First we investigated the presence and the frequency of mutations in 8 genes commonly mutated in colon cancer in the cohort of patients under analysis: APC was mutated in 54% of samples, TP53 in 62% of samples, PI3KCA in 20% of samples, ARID1A in 48.6% of samples, KRAS in 27% of samples, BRAF in 11% of samples, DCC in 8% of samples and SMAD4 in 5.4% of samples.