Distant metastasis is one of the crucial parameters determining the type of treatment and prognosis of patients. Previous studies discovered important factors involved in multiple steps of metastasis, the precise mechanisms of metastasis still remain to be clarified. To identify genes associated with this complicated biological feature of cancer, we analyzed expression profiles of 16 metastatic brain tumors derived from primary lung adenocarcinoma (ADC) using cDNA microarray representing 23,040 genes. We applied bioinformatic algorithm to compare the expression data of these 16 brain metastatic loci with those of 37 primary NSCLCs including 22 ADCs, and found that metastatic tumor cells has very different characteristics of gene expression patterns from primary ones. Two hundred and forty-four genes that showed significantly different expression levels between the two groups included plasma membrane bounding proteins, cellular antigens, and cytoskeletal proteins that might play important roles in altering cell-cell communication, attachment, and cell motility, and enhance the metastatic ability of cancer cells. Our results provide valuable information for development of predictive markers as well as novel therapeutic target molecules for metastatic brain tumor of ADC of the lung.