ADAMTS (a disintegrin and metalloproteinase domain with Thrombospondin type-1 modules) is a family of zinc-dependent proteases that are implicated in a variety of normal and pathological conditions, including arthritis and cancer. ADAMTS protein family members contain an amino-terminal propeptide domain, a metalloproteinase domain, a disintegrin-like domain and a carboxy-terminus that contains a varying number of thrombospondin 1 (TSP 1) motifs. ADAMTS genes are primarily expressed in fetal tissues, including the lung, kidney and liver. ADAMTS-18 is a secreted protein that is also expressed in adult brain, endothelium, prostate and submaxillary gland. ADAMTS-18 has two known splice variants and it is structurally most similar to ADAMTS-16. ADAMTS-18 is downregulated in carcinoma cell lines by methylation of its promoter. Forced expression of ADAMTS-18 in carcinoma cells can lead to significant inhibition of cell growth, suggesting that it plays a significant role as a tumor suppressor.