Moreover, we observed that in I-10 cells derived from mouse testicular Leydig cell tumors, the mRNA expression level of DAPL1 was markedly lower than that in the testis (Fig. S3); this could be attributed to the low expression of DAPL1 in Leydig cells in contrast to the high expression observed in other cell types within the testis. This evidence concerns the gene DAPL1 and Leydig cell tumor.