Some groups find little to no evidence of CMV in GBM and other brain tumor tissues, and some groups find evidence of CMV in virtually every GBM sample. It might depend on which group is doing the looking and especially the techniques being used.See Charles Cobbs' reply to a different study that also failed to detect CMV infection of GBM using standard methods:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4201079/pdf/nou295.pdf
http://cancerres.aacrjournals.org/content/76/18/5326.article-infoThis recent study by Martha Chekenya Enger et al, confirms the presence of CMV in a significant number of GBMs. It is based on a large sample group and uses the same methodology as Söderberg-Naucler, Stragliotto et al and that of Cobbs.In addition to finding a number of seropositive GBMs, they investigate the interaction between CMV infection and immune response, specifically NK & T cell activation: 'By affecting immunological presentation, the presence of cytomegalovirus in some glioblastomas may impact progression. In this study, we examined a hypothesized role for natural killer (NK) cells in impacting disease progression in this setting.' They propose to use NK cells as therapeutic effectors in vaccines. Furthermore, they also identify the role of a Killer cell Immunoglobulin-like Receptor (KIR) allele whereby: 'KIR2DS4*00101 may offer a molecular biomarker to identify intrinsically milder forms of glioblastoma.' and ' Our results reveal for the first time the association of a specific KIR2DS4*00101 gene allele with protection from glioblastoma development and enhanced survival in patients who do contract glioblastoma. This novel finding is of direct clinical relevance for the identification of patients who may exhibit a less aggressive clinical course and who may potentially respond to immunotherapy.'I believe they are publishing a follow up to this line of investigation this spring.