PRSS21 and neoplasm: Similar to our observations on the Testisin gene, hypermethylation of both prostasin and NES1 genes has been reported as the basis for loss of expression of these genes in tumours (Li et al, 2001; Chen and Chai, 2002), and their effects on cells are not associated with reduced proliferation (Goyal et al, 1998; Chen et al, 2001).