title: Foci formation of P53-binding protein 1 in thyroid tumors: activation of genomic instability during thyroid carcinogenesis.
abstract: Defective DNA damage response (DDR) can result in genomic instability (GIN) and lead to the transformation into cancer. P53-binding protein 1 (53BP1) belongs to a family of evolutionarily conserved DDR proteins. Because 53BP1 molecules localize at the sites of DNA double strand breaks (DSBs) and rapidly form nuclear foci, the presence of 53BP1 foci can be considered as a cytologic marker for endogenous DSBs reflecting GIN. Although it has been proposed that GIN has a crucial role in the progression of thyroid neoplasms, the significance of GIN during thyroid tumorigenesis remains unclear, particularly in patients. We analyzed, therefore, the level of GIN, as detected with immunofluorescence of 53BP1, in 40 cases of resected thyroid tissues. This study demonstrated a number of nuclear 53BP1 foci in thyroid cancers, suggesting a constitutive activation of DDR in thyroid cancer cells. Because follicular adenoma also showed a few 53BP1 nuclear foci, GIN might be induced at a precancerous stage of thyroid tumorigenesis. Furthermore, high-grade thyroid cancers prominently exhibited an intense and heterogeneous nuclear staining of 53BP1 immunoreactivity, which was also observed in radiation-associated cancers and in mouse colonic crypts as a delayed response to a high dose ionizing radiation, suggesting increased GIN with progression of cancer. Thus, the present study demonstrated a difference in the staining pattern of 53BP1 during thyroid carcinogenesis. We propose that immunofluorescence analysis of 53BP1 expression can be a useful tool to estimate the level of GIN and, simultaneously, the malignant potency of human thyroid tumors.
authors.affiliation: Division of Scientific Data Registry, Atomic Bomb Disease Institute, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan. moemoe@nagasaki-u.ac.jp
authors.forename: Masahiro
authors.initials: M
authors.lastname: Nakashima
authors.forename: Keiji
authors.initials: K
authors.lastname: Suzuki
authors.forename: Serik
authors.initials: S
authors.lastname: Meirmanov
authors.forename: Yuki
authors.initials: Y
authors.lastname: Naruke
authors.forename: Mutsumi
authors.initials: M
authors.lastname: Matsuu-Matsuyama
authors.forename: Kazuko
authors.initials: K
authors.lastname: Shichijo
authors.forename: Vladimir
authors.initials: V
authors.lastname: Saenko
authors.forename: Hisayoshi
authors.initials: H
authors.lastname: Kondo
authors.forename: Tomayoshi
authors.initials: T
authors.lastname: Hayashi
authors.forename: Masahiro
authors.initials: M
authors.lastname: Ito
authors.forename: Shunichi
authors.initials: S
authors.lastname: Yamashita
authors.forename: Ichiro
authors.initials: I
authors.lastname: Sekine
mesh_terms: D000236:Adenoma / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D002277:Carcinoma / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D002467:Cell Nucleus / Q000378:metabolism; D003106:Colon / Q000378:metabolism; D005260:Female; D005455:Fluorescent Antibody Technique; D042822:Genomic Instability; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008875:Middle Aged; D013964:Thyroid Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D000071857:Tumor Suppressor p53-Binding Protein 1
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; C498301:TP53BP1 protein, human; D000071857:Tumor Suppressor p53-Binding Protein 1