The invention relates to the nucleic acid sequences of two novel human ARL-related gene variants (ARLV1 and ARLV2) and the polypeptides encoded by ARLV1 and ARLV2.The invention also relates to the process for producing the polypeptides encoded by ARLV1 and ARLV2.The invention further relates to the use of the nucleic acid of ARLV1 and ARLV2 and the polypeptide encoded by ARLV1 and ARLV2 in diagnosing diseases associated with the deficiency of human ARLV gene, in particular large cell lung cancer or hepatocellular carcinoma.