Inversely, mucinous adenocarcinoma mucus was positive for MUC5AC, whereas MUC5B and BPIFB1 are largely negative at the immunofluorescence level (Fig. 8E, white arrows point where MUC5B/BPIFB1 are absent). The gene discussed is BPIFB1; the disease is colon mucinous adenocarcinoma.