Because PNA can enhance tumour cell-endothelial cell adhesion directly by interaction with cell surface MUC1 on tumour cells (12), MUC1-negative human colon cancer HCT116 and melanoma ACA19-cells were used here to avoid the PNA-MUC1-mediated influence on cancer cell interaction. This evidence concerns the gene MUC1 and malignant colon neoplasm.