TGFB1 and head and neck squamous cell carcinoma: On the other hand, inhibition of TGF‐β using the TGF‐β receptor type 1 inhibitor SB431542 reduced the invasion of TGF‐β‐responsive HNSCC keratinocytes into 3D organ cultures, with little change to proliferation in 2D culture (supplementary material, Figure S3A–C).