Muc5ac 45m1

We used commercially available tissue microarray (TMA) (Cat#HLugA150CS02; US Biomax, Rockville, MD, USA), which included 75 cases of LUAD and normal lung tissues. The TMA was analyzed for ST6GalNAc‐I (Cat#ab82821), MUC5AC [45M1] (Cat#ab3649; Abcam, Cambridge, MA, USA), and STn (Cat#LS‑C170901; clone B35.1; LSBio, Seattle, WA, USA) expression by immunohistochemistry (IHC), as described previously [25].

Antibodies against phospho-EGFR (Tyr1068), EGFR and MUC5AC (45 M1) were obtained from Abcam (Cambridge, MA, USA). Antibodies against phospho-ERK (Thr202/Tyr204) and ERK, and PD98059 were from Cell Signaling Technology (Danvers, MA, USA). The anti-EGFR neutralizing antibody was from Chemicon (Temecula, CA, USA). The other neutralizing antibodies (anti-TGF-α, anti-AR, and anti-HB-EGF), species- and isotype-matched control antibodies and recombinant AR were from R&D Systems, Inc. (Minneapolis, MN, USA). The GAPDH antibody was from TDYbio (Beijing, China). The MUC5B antibody was obtained from Santa Cruz Biotechnology (Santa Cruz, CA, USA). AG1478, GM6001, TAPI-1 and actinomycin D were purchased from Calbiochem (San Diego, CA, USA). Unless stated otherwise, all other reagents were obtained from Sigma-Aldrich (St. Louis, MO, USA).