ONCOmmunity

Detection of Endogenous DNA Double-strand Breaks in Oral Squamous Epithelial Lesions by P53-binding Protein 1.

By: Toshinobu Imaizumi, Katsuya Matsuda, Kei Tanaka, Hisayoshi Kondo, Nozomi Ueki, Hirokazu Kurohama, Chieko Otsubo, Yuki Matsuoka, Yuko Akazawa, Shiro Miura, Masahiro Nakashima

Department of Tumor and Diagnostic Pathology, Atomic Bomb Disease Institute, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.
2021-06-27; doi: 10.21873/anticanres.15292

Abstract

Background/aim

P53-binding protein 1 (53BP1) is one of the DNA damage response (DDR) molecules. This study aimed to assess 53BP1 expression by immunofluorescence (IF) as a biomarker to differentiate between oral squamous epithelial lesions (OSELs).

Materials

We analyzed 129 archival oral biopsy samples, including 18 benign squamous lesions (BSLs), 37 low-grade dysplasias (LGDs), 22 high-grade dysplasias (HGDs), and 52 oral squamous cell carcinomas (OSCCs). 53BP1 and Ki-67 expressions were examined by double IF to assess the type of 53BP1 expression.

Results

We found that OSCC exhibited several 53BP1 nuclear foci, particularly high-DNA damage response (HDDR) and large focus (LF)-type, suggesting the presence of endogenous DNA double-strand breaks in the cancer genome, which could disrupt DDR and induce genomic injury. We also found a difference in 53BP1 expression between LGD and HGD, but not between BSL and LGD. Among the Ki-67-positive cells, HDDR- and LF-type expressions were higher in OSELs of higher grades.

Conclusion

53BP1 expression can be a valuable biomarker for OSELs to help estimate the grade of oral epithelial dysplasia.