Interestingly, some NKG2D ligands (MICA, MICB, ULBP-2 and ULBP-3) are secreted from NSCLC [33], osteosarcomas [44] and gastric [45] cancer cells and may be shed by MMP-mediated cleavage. This evidence concerns the gene ULBP3 and non-small cell lung carcinoma.