The current view on HPV contribution on cervical cancer is that 100% of teh cases are attributable to HPV persistent infection. However, this absolute presence is rarely seen in the field studies or in the clinical settings. Concern of potential false negatives cases has become more worrisome due to the upcoming screening algorthims using HPV tests as primary selection process in cervical cancer screening.
Histological confirmed ICC cases from 38 countries were assembled. HPV detection was done by polymerase chain reaction using SPF-10 broad-spectrum primers followed by deoxyribonucleic acid enzyme immunoassay and genotyping by reverse hybridization line probe assay (LiPA25) (version 1). Several steps were taken to evaluate the potential reasons fro a false negative result: HPV DNA negative samples were evaluated for DNA quality for PCR analysis by the application of different primers for ß-globin and ß-Actin PCR amplification generating different amplimer lengths. Besides broad spectrum PCR we also tested with 14 different hr HPV Type Specific PCRs. Adenocarcinomas were reviewed by a panel of expert pathologists
Of 10,575 ICC cases, 8,977 were HPV-DNA positive (84.9%). The diagnosis with the lowest HPV positivity was ADC (61.8%), followed by the “other” category (72.5%) and ADSCC (81.2%). Among HPV DNA negative samples 60% were also ß-globin and ß-Actin PCR negative. In the remaining 40% of the HPV negative samples showed no signs of PCR inhibition after spiking these samples with HPV DNA and performing HPV type specific tests. Additional evaluation of these HPV negative specimens both in the quality of the specimen and the pathology processing as well as in the HPV testing methodology indicated that low viral load, tissue degradation could account for less than 10% of negative ADC. Missdiagnosis of ADC was not identified as playing a major role. Preservation of the tissue may be related to unmeasured factors that could explaine results.Further analysis will be presented to explore factors linked to a negative result.
Several issues can be involved in a false negative HPV result when using repository samples. The impact of them is unlikely to affect the genotype distribution of the positive samples. False negative data can be minimized when using recent and well preserved samples.