PRF1 and neoplasm: For example, an array study identified methylation in seven known or candidate tumour suppressor genes (including VHL, ABI3, and IGSF4) as well as eight unmethylated genes involved in cell proliferation and tumour progression (including ADORA3 and PRF1) in Swedes with immunoglobulin heavy chain gene variable region (IGHV)-unmutated CLL9.