TGFB1 and head and neck squamous cell carcinoma: Kloss et al. show that patients with head and neck squamous cell carcinomas (HNSCCs) have elevated levels of soluble major histocompatibility complex class I chain-related peptide A (sMICA) and transforming growth factor beta 1 (TGF-β1) in serum, which are responsible for the impaired NK cell effector functions and decreased NKG2D expression.