MUC5AC and cancer: Among the subpyloric lymph node metastases, one lymph node metastasis was of gastric origin and the other of duodenal origin. Immunostaining histopathological examinations showed mucin 5AC (MUC5AC) positivity in both gastric and duodenal cancers, mucin 6 (MUC6) positivity in only duodenal cancer, and CD10 and MUC2 negative staining for both cancers (Figure 5).