Beryllium is used extensively in various industrial applications and many workers are potentially exposed to toxic levels of this metal. Even though laboratory studies have documented the carcinogenic potential of beryllium in experimental animals. The underlying molecular mechanisms are poorly understood. In order to elucidate the molecular mechanisms of beryllium-induced tumorigenesis, we have studied the various cancer-related genes that were altered as a result of cellular transformation induced by beryllium. BALB/c-3T3 cells, morphologically transformed with beryllium, were subcutaneously injected into nude mice to develop tumors. DNA and ANA isolated from cell lines derived from the tumors were used to determine the alterations of various cancer-related genes, such as p53, p16, K-ras, c-myc, c-fos. c-jun, c-sis and erbB1. Alterations of the copy number and expression of the genes were studied by differential PCA and ATPCA, respectively. Both the gene copy number and expressions of K-ras, c-fos and c-jun were higher in the tumor cells compared to those of the control Balb/c-3T3 cells. In contrast, p16 exhibited a decrease in both the gene copy number and expression in the tumor cells compared to those of the control cells. These results suggest that beryllium-induced tumorigenesis is associated with alterations of various cancer-related genes, and these alterations may play a role in beryllium-induced tumorigenesis.