Cytomegalovirus infection and cervical cancer: from past doubts to present questions.

BACKGROUND Since early 60's that Cytomegalovirus was studied for its possible role in cervical cancer development. Despite several decades of studies and the description of CMV DNA in cervical samples, it is still doubtful what is the prevalence of Cytomegalovirus in cervix and if CMV can act as a co-factor in cervical carcinogenesis. METHODS In this Systematic Review we intend to summarize the frequency of Cytomegalovirus in cervical samples by revising all published studies between 1980 and 2011 regarding the detection of Cytomegalovirus in cervical samples and the development of lesions/ invasive cervical cancer. Crude and adjusted frequencies of Cytomegalovirus infection were calculated according to country and world region. RESULTS This study revealed that the worldwide crude frequency of Cytomegalovirus infection in the cervix was 18.9% in all cervical samples and 36.5% in HPV positive women. Cytomegalovirus infection was present in all different types of lesions: 17.4% in normal/ cervicitis, 28.0% in LSIL, 19.7% in HSIL and 44.4% in CIS/ICC. The overall rate of Cytomegalovirus infection varied from 1.58% to 61.0% with an increased incidence in less developed countries. CONCLUSION In this study we described a high frequency of positive Cytomegalovirus cases in all types of cervical samples, with increased incidence in both HPV-infected women and CIS/ICC cases. Hence, despite results showed that Cytomegalovirus shedding in cervical samples is frequent more studies should be performed to clarify if Cytomegalovirus infection is an opportunistic infection in HPV-infected cases, or if it contributes for cervical immunosuppression that will favor HPV-associated carcinogenesis.