【 Abstract 】 Objective To study the mRNA expression of BC047440 gene in multiplicate malignant tumor tissues and the corresponding adjacent tissues, and to investigate its roles in the carcinogenesis and development of malignant tumors. Methods Forty-eight cases of malignant tumor tissues and their adjacent non-cancerous tissues were examined. The mRNA expression of BC047440 gene in those tissues of liver cancer, cholangiocarcinoma, gastric cancer, carcinoma of large intestine, glioma, and breast cancer were measured by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR). Results ① The mRNA expressions of BC047440 gene in liver cancer, gastric cancer, cholangiocarcinoma and carcinoma of large intestine were significantly higher than those in their adjacent non-cancerous tissues (Plt;0.05 or 0.01). BC047440 gene were highly expressed in both glioma and its adjacent tissues (Pgt;0.05), and poorly expressed in both breast cancer and its adjacent tissues (Pgt;0.05). ② There were close relationships between BC047440 gene expression and clinicopathologic findings of liver cancer, including tumor size and portal vein invasion (Plt;0.05). ③ There were also close relationships between BC047440 gene expression and different clinical stages in alimentary canal cancers (Plt;0.05). Conclusion The over expression of BC047440 gene may be related with the growth, infiltration and metastasis of some malignant tumors, including liver cancer, cholangiocarcinoma, gastric cancer, carcinoma of large intestine and glioma.