That the Testisin gene is silenced by DNA hypermethylation was demonstrated by (i) the correlation of CpG island methylation status with gene expression in tumour cell lines and in primary testicular tumour tissues (Figures 1 and 2) and (ii) re-expression of Testisin mRNA following demethylation and histone deacetylase inhibition (Figure 3). Here, PRSS21 is linked to neoplasm.