MUC5AC and gastric cancer: Therefore, to ascertain whether the Winnie mutation affects biosynthesis of Muc2, we cloned partial cDNAs encoding the Winnie and wild-type Muc2 N-terminal D3 oligomerisation domain (rMuc2-D3, Figure 2C) and expressed these as recombinant proteins in MKN45 gastric cancer cells which produce the MUC5AC mucin (but not MUC2) and are therefore likely to express mucin-specific chaperones.