Background and Objective: Elevated expression of matrix metalloproteinases (MMPs) has been found in multiple carcinoma tissues.MMP-26 is highly expressed in prostate and breast cancer tissues,and promotes the invasion of human prostate cancer cells not only through the cleavage of fibronectin and type Ⅳ collagen but also by the activation of pro-MMP-9,a powerful gelatinase. This study was to present a comprehensive protein expression profile of MMP-26 in multiple human cancer tissues. Methods: The protein expression pattern of MMP-26 was examined using immunohistochemistry and multiple-tissue microarray. MMP-26 mRNA expression in coronary artery smooth muscle cells was detected by reverse transcription-polymerase chain reaction(RT-PCR). Results: The expression of MMP-26 in breast,colon,lung, brain, head and neck, prostate cancer, and melanoma tissues was significantly elevated when compared with parallel normal tissues (P＜0.05), while not significantly elevated in kidney cancer,ovarian cancer,and non-Hodgkin's lymphoma (P＞0.05).MMP-26 was also detected to express in gastric,rectal,thyroid, esophageal,and pancreatic cancers.MMP-26 protein was expressed in smooth muscle cells of the prostate and associated blood vessels. MMP-26 mRNA was also detected to express in human coronary artery smooth muscle cells. Conclusions: MMP-26 expression may be associated with multiple human carcinomas,and it may serve as a molecular marker for the early diagnosis of these carcinomas.MMP-26 may also contribute to smooth muscle function in the human prostate and cardiovascular system.