PRSS21 and neoplasm: There appeared to be an increased number of semimethylated CpG sites in the 5′ untranslated region of the Testisin gene in the tumour specimens compared with the large number of methylated sites in the proximal promoter and exon I. Thus, the Testisin gene methylation patterns and silencing observed in testicular tumour cell lines reflects aberrations present in primary testicular tissues.