The present invention is directed to the use of the expression level of the pro-EPIL gene as a biomarker for the diagnosis of testicular cancer, particurarly a testicular germ cell tumor: the invention also relates to an in vitro method for detecting and/or classifying a testicular cancer in subject comprising a step of determining the expression level of the gene encoding the pro-EPIl peptide in a biological, particularly in combination with the determination of the beta subunit HCGBeta and the human alpha-fetoprotein AFP. The invention is also directed to a kit or solid support comprising nucleic acids or antribodies capable of determinig the presence or the expression level of these three biological markers
