부산대학교 도서관

To purchase or authenticate to the full-text of this article, please visit this link: http://dx.doi.org/10.1111/j.1349-7006.2008.00786.x Byline: Yuki Naruke (2), Masahiro Nakashima (1,5), Keiji Suzuki (3), Mutsumi Matsuu-Matsuyama (2), Kazuko Shichijo (2), Hisayoshi Kondo (4), Ichiro Sekine (1,2) Abstract: Epidermal cells are the first cells to be exposed to environmental genotoxic agents such as ultraviolet and ionizing radiations, which induce DNA double strand breaks (DSB) and activate DNA damage response (DDR) to maintain genomic integrity. Defective DDR can result in genomic instability (GIN) which is considered to be a central aspect of any carcinogenic process. P53-binding protein 1 (53BP1) belongs to a family of evolutionarily conserved DDR proteins. Because 53BP1 molecules localize at the sites of DSB and rapidly form nuclear foci, the presence of 53BP1 nuclear foci can be considered as a cytological marker for endogenous DSB reflecting GIN. The levels of GIN were analyzed by immunofluorescence studies of 53BP1 in 56 skin tumors that included 20 seborrheic keratosis, eight actinic keratosis, nine Bowen's disease, nine squamous cell carcinoma, and 10 basal cell carcinoma. This study demonstrated a number of nuclear 53BP1 foci in human skin tumorigenesis, suggesting a constitutive activation of DDR in skin cancer cells. Because actinic keratosis showed a high DDR type of 53BP1 immunoreactivity, GIN seems to be induced at the precancerous stage. Furthermore, invasive cancers exhibited a high level of intense, abnormal 53BP1 nuclear staining with nuclear accumulation of p53, suggesting a disruption of DDR leading to a high level of GIN in cancer cells. The results of this study suggest that GIN has a crucial role in the progression of skin carcinogenesis. The detection of 53BP1 expression by immunofluorescence can be a useful histological marker to estimate the malignant potential of human skin tumors. (Cancer Sci 2008; 99: 946-951) Author Affiliation: (1)Tissue and Histopathology Section, Division of Scientific Data Registry, (2)Department of Tumor and Diagnostic Pathology, (3)Department of Molecular Medicine, (4)Biostatics Section, Division of Scientific Data Registry, Atomic Bomb Disease Institute, Nagasaki University Graduate School of Biomedical Sciences, 1-12-4 Sakamoto, Nagasaki, 852-8523, Japan Article History: (Received December 13, 2007/Revised January 21, 2008/Accepted January 23, 2008/Online publication March 13, 2008) Article note: (5) To whom all correspondence should be addressed. E-mail: moemoe@nagasaki-u.ac.jp