HPV-ISH-Negative Invasive Cervical Squamous Cell Carcinoma: Histologic and Pap Test Results

A causal link between infection with a high-risk strain of human papilloma virus (hrHPV) and the development of cervical squamous cell carcinoma (SCC) is well established. However, a small number of SCCs are hrHPV-negative by either HPV co-DNA testing and/or HPV-in situ hybridization (HPV-ISH) at the time of diagnosis. These apparently hrHPV-negative lesions are poorly understood, specifically whether hrHPV-positive precursor lesions exist, which would be detected through hrHPV-based screening.

A search of the pathology archives at the Johns Hopkins Hospital identified women with a diagnosis of hrHPV-negative cervical SCC on surgical specimen. All prior pathologies, including cervical cytology and surgical pathology specimens, and associated hrHPV DNA test results, p16 immunohistochemistry, and HPV-ISH were reviewed.

A total of 25 women were identified having a surgical specimen diagnosed as SCC with either negative or equivocal HPV-ISH. Fifteen had a Pap test in the 6 months preceding a diagnosis of SCC, with cytology diagnoses as follows: high-grade squamous intraepithelial lesion n = 14/15; atypical squamous cells, cannot exclude high-grade squamous intraepithelial lesion n = 1/15. hrHPV co-testing was performed for 5 of these 15 women and was negative in 2/5 cases. Cervical biopsy was performed for 24 women. HPV-ISH testing, performed on 14 of the biopsy specimens, was negative for 11/14 patients. Of 15 specimens stained for p16, 14 were positive.

A subset of patients exist in whom hrHPV is not detectable at or near the time of progression to SCC. Additional research is necessary to further describe this population and determine whether maintaining cytological screening would provide benefit.