MUC5AC and cancer: Similarly, Reynolds and coworkers recently conducted a systematic literature review on the apoptosis-blocking function of mucin glycoproteins and identified 90 studies which show evidence that MUC1, MUC2, MUC4, MUC5AC, MUC5B, MUC13, and MUC16 are involved in apoptosis resistance or cancer drug resistance in epithelial cancer cells [18].