Many factors contribute to Cancer, but the key catalyst (even the underlying engine) is one of many Viruses, particularly CMV, but also VZV, Epstein Barr as well as other Viruses SV-40, BK, JCV and HPV. Each cancer in our body has one to many viruses associated with it. Some key ones are HPV – Human Papilloma Virus causes Cervical, Anal, Mouth, Throat, Lung, Vaginal and Penile Cancers. Epstein Barr causes Lymphoma, JC Polyoma Virus causes Colon Cancer. Epstein Barr, HPV & CMV have all been associated with Breast Cancer, thus one reason for it’s prevalence. Now down to kids Cancer, Medulloblastoma Neuroblastoma and it’s 99% terminal twin cancer Glioblastoma. For these cancers its mainly CMV (Human Cytomegalovirus), though other viruses like SV-40, JC and BK are also capable and have been found in these tumors.