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Human papillomavirus status and the relative biological effectiveness of proton radiotherapy in head and neck cancer cells
Author(s) -
Wang Li,
Wang Xiaochun,
Li Yuting,
Han Shichao,
Zhu Jinming,
Wang Xiaofang,
Molkentine David P.,
Blanchard Pierre,
Yang Yining,
Zhang Ruiping,
Sahoo Narayan,
Gillin Michael,
Zhu Xiaorong Ronald,
Zhang Xiaodong,
Myers Jeffrey N.,
Frank Steven J.
Publication year - 2017
Publication title -
head and neck
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.012
H-Index - 127
eISSN - 1097-0347
pISSN - 1043-3074
DOI - 10.1002/hed.24673
Subject(s) - clonogenic assay , head and neck cancer , relative biological effectiveness , radiation therapy , cancer cell , cancer research , cancer , human papillomavirus , cell culture , medicine , oncology , biology , irradiation , physics , genetics , nuclear physics
Background Human papillomavirus (HPV)‐positive oropharyngeal carcinomas response better to X‐ray therapy (XRT) than HPV‐negative disease. Whether HPV status influences the sensitivity of head and neck cancer cells to proton therapy or the relative biological effectiveness (RBE) of protons versus XRT is unknown. Methods Clonogenic survival was used to calculate the RBE; immunocytochemical analysis and neutral comet assay were used to evaluate unrepaired DNA double‐strand breaks. Results HPV‐positive cells were more sensitive to protons and the unrepaired double‐strand breaks were more numerous in HPV‐positive cells than in HPV‐negative cells ( p < .001). Protons killed more cells than did XRT at all fraction sizes (all RBEs > 1.06). Cell line type and radiation fraction size influenced the RBE. Conclusion HPV‐positive cells were more sensitive to protons than HPV‐negative cells maybe through the effects of HPV on DNA damage and repair. The RBE for protons depends more on cell type and fraction size than on HPV status. © 2016 Wiley Periodicals, Inc. Head Neck 39: 708–715, 2017