The invention relates to the nucleic acid and polypeptide sequences of three novel human Ron-related gene variants (Ron-V1, Ron-V2, and Ron-V3). The invention also provides a process for producing the polypeptides of the variants, as well as uses for the nucleic acid, polypeptide and antibodies to same in diagnosing human breast carcinoma, breast adenocarcinoma, cervix epidermoid carcinoma, cervix epitheloid carcinoma, colon adenocarcinoma, urinary bladder carcinoma, prostate carcinoma, esophagus epidermoid carcinoma and esophagus carcinoma.