**3. Etiology**

The etiologies of medulloblastoma are still obscure for most patients. Though Parental pesticide use and parental occupational contact with hydrocarbons, exposure to N-nitroso compounds and metals have been associated with higher incidence in some studies [25].

For development of medulloblastoma, the most ventured postulation in the earlier literatures was cell misplacements during early embryonic development where genetic factors play vital role [9]. This has been proven true with time with the advancement of genetic studies. Association between several familial cancer syndromes in children with medulloblastomas like TP53 germline mutation syndromes, Gorlin syndrome, and Turcot syndrome also supports predisposition of hereditary factors [8].

Studies have identified Human Cytomegalovirus (HCMV) protein pp65 immunoreactivity in medulloblastomas, but the oncogenic role of HCMV is still debated. Yet HCMV is believed to play role as a significant oncomodulator and based on that researchers are on the quest to utilize the potential of HCMV as a novel immunotherapeutic agent [25, 27–29].
