In findings with potentially important implications for cervical cancer screening, scientists at the National Cancer Institute (NCI)-designated Montefiore Einstein Cancer Center (MECC) have developed a test for detecting a type of cervical cancer that Pap tests often miss. The findings published online in the Journal of the National Cancer Institute (JNCI).
“Our novel test appears sensitive for detecting cervical adenocarcinoma [ADC]—which now accounts for up to 25% of cervical cancer cases—as well as its precursor lesions, adenocarcinoma in situ [AIS], that often develop into ADCs,” said Howard Strickler, M.D., M.P.H., co-senior and corresponding author of the JNCI paper and a member of MECC.
The MECC-developed HPV test assessed HPV 16, 18, and 45 in a novel way: by specifically looking at methylation levels.
Methylation—the addition of methyl (CH3) groups to a region of DNA—is a routine occurrence in DNA, both viral and human, and plays a critical role in altering gene expression. The JNCI study, a collaborative project with the NCI, part of the National Institutes of Health, investigated methylation levels in cervical tissue samples from 1,400 women who had undergone cervical cancer screening at Kaiser Permanente Northern California before 2014 and whose cervical cancer status was known.
In assessing the HPVs in the cytological samples, the researchers tallied up the methylation percentages for each of 35 different viral-genome sites, with each sample receiving a final “methylation score” equal to the average methylation percentage across all 35 sites. Those women with methylation scores in the upper 25% had very high odds for having developed either ADC or AIS.