Determination of the potential of detecting 3q gain as a valuable biomarker in the management of patients with human papilloma virus (HPV) associated oropharyngeal squamous cell carcinoma (OPSCC).

Abstract

e17534 Background: The most recurrent structural chromosomal aberration in HPV associated cervical cancer is gain of the 3q26 locus testing of which has clinical utility in management of patients with cervical lesions. A significant proportion of OPSCC are HPV mediated, suggesting the possibility of a common disease mechanism. The objective of this study is to determine the potential clinical validity of assessing 3q gain as a biomarker in the management of patients with HPV associated OPSCC. Methods: An oral swab using a cytological brush was obtained of the region containing visualized tumor site in newly diagnosed HPV associated OPSCC patients following written informed consent of an IRB approved protocol at the University of Connecticut. The swabs were obtained at the diagnosis and serially after chemotherapy and/or chemo-radiotherapy as well as at 3 months after treatment completion. The specimens’ 3q gain status was determined by fluorescent in situ hybridization (FISH) analysis, utilizing robotic fluorescence microscopy for detection of rare cells demonstrating high 3q26 copy number Results: 54 specimens were collected from 13 patients, of which slides were prepared, hybridized and analyzed from 50. Data was not available in four specimens due to insufficient cells while for eight patients, multiple specimens were obtained before, during and after 3 months of treatment. Depending on the specimen’s cellularity, up to 170,969 cells were analyzed. Cells with > 4 copies of the 3q26 locus were detected in 32 of the 50 analyzable specimens. For several patients, the number of cells with more than four 3q26 signals detected in the later time points of treatment was lower than the number detected at diagnosis. Conclusions:This preliminary dataset demonstrates the ability to detect gain of the 3q26 locus in cells collected by cytological brushing of the region containing an OPSCC. The approach offers the possibility of a minimally invasive method to determine the 3q26 gain status as a reliable biomarker of HPV associated OPSCC that might have value in early diagnosis and management.