Cancer cells which express certain type of mucins (MUC1, 4, 5 AC, 6, 13, 16 and 20) are resistant to chemotherapeutic drugs due to the physiological mucin barrier, drug efflux proteins, resistance to apoptosis, stem cells, and transition from epithelial to mesenchymal phenotype [10, 11]. This evidence concerns the gene MUC5AC and cancer.