Possibly carcinogenic HPV subtypes are a cause of HSIL and negative clinical HPV tests – A European prospective single center study

Objective To correlate p16ink4a positive cervical precancers of 388 consecutive patients from a single European center with the preceding clinical HPV-DNA and HPV E6/E7 mRNA screening test. Method 374/388 patients had a HSIL (CIN 2/3) and 14/388 AIS (6 pure and 8 combined AIS/HSIL). Lesional tissues of HSIL/AIS with negative Cobas and/or Aptima HPV tests underwent HPV genotyping with CHIPRON HPV 3.5 LCD-array. Selected cases were subjected to a cancer hot spot analysis. Results The Aptima test missed 10/388 (2.6%) and the Cobas test seven of 388 (1.8%) precancers associated HPV-HR. Both HPV tests were negative in 20/374 precancers (5.3%; 17 HSIL/CIN3, two HSIL/CIN2, one AIS). Due to insufficient DNA four of 20 double negative cases (three HSIL, one AIS) were not genotyped. In the remaining cases, two of 20 (10%) HSIL genotyping detected HR-HPV subtypes. 10/20 (50%) HSIL were associated with possibly carcinogenic and low risk HPV (four x HPV73, three x HPV 53, one x HPV 82, one x HPV 67 and one x HPV 6), all of which are not included in both HPV tests. Two of 20 (10%) HSIL were negative with all HPV tests; one of these HSIL had a somatic PIK3CA gene mutation and the other had a single nucleotide variant in the APC gene. Three of 20 HSIL (15%) were thin HSIL (≤9 cell layers thick). Conclusions Possibly carcinogenic HPV subtypes not included in the clinical HPV tests may account for the small gap of missed HSIL in clinical HPV screening. True HPV negative HSIL are exceedingly rare. Expanding HPV testing to include more possibly carcinogenic HPV subtypes may further reduce cervical cancer.