GAPDH and melanoma: We measured copies of both cellular and viral DNA using primers to VZV open reading frame 62 (ORF62) and ORF68 and the cellular gene coding for GAPDH (glyceraldehyde-3-phosphate dehydrogenase) in the brain tissue, along with both positive (DNA from VZV infected melanoma cells) and negative (DNA from water) controls (Fig. 1A).