Recently, it has been shown that ectopic expression of several germ line genes, such as piwi, vasa, nos and aub, drives the growth of malignant brain tumors in Drosophila. A genome-wide association study (GWAS) of ~18 000 subjects indicated that genetic variation at 22q12.2, the location of the conserved meiotic gene HORMAD2, may contribute to the risk of lung cancer in Han Chinese individuals. The expression pattern of human HORMAD2 in multiple human tissues was determined by RT-PCR. HORMAD2 protein expression and localization were analyzed in the human testis using immunohistochemistry. The expression of HORMAD2 in lung cancer and normal tissues was studied using quantitative RT-PCR and immunohistochemistry. HORMAD2 is predominantly expressed in human testis and weakly expressed in liver. HORMAD2 is ectopically expressed in nearly 10% of lung cancer samples from Chinese Han individuals. In conclusion, HORMAD2 is a novel cancer/testis gene discovered by GWAS, which may provide a new target for lung cancer research.