Takashi Saku

Niigata University, Niahi-niigata, Niigata, Japan

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Publications (186)295.71 Total impact

  • Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology. 03/2015; 119(3):e146-e147.
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    ABSTRACT: Background Oral pemphigus vulgaris (PV), an autoimmune blistering disease, is mainly mediated by autoantibodies against desmoglein (Dsg) 3. However, no attention has been paid to IgG subclasses of the autoantibodies against Dsg3 in the diagnostic procedure for PV. Thus, our aim in this study was to investigate whether Dsg3 and any of IgG subclasses are immunohistochemically colocalized in tissue sections of PV oral mucosa.Materials and Methods Serial sections cut from formalin-fixed paraffin blocks of biopsy specimens of 9 PV cases and those of normal buccal mucosa surgically removed for fibro-epithelial polyps were comparatively examined for immunohistochemical localizations for Dsg3, IgG4, and IgG.ResultsDsg3 was demonstrated in a dot-like pattern on the cell border and in the cytoplasm of the whole epithelial layer in both normal and PV specimens, while its staining was irregular among floating epithelial sheets of PV. IgG4 was also demonstrated in a punctuated fashion on the cell border among floating epithelial sheets, which was nearly identical to the immunohistochemical profile of Dsg3. In addition to being detected in the epithelial part, IgG4 signals were prominently localized in plasma cells scattered in the granulation tissue, where ratios of IgG4-positive (+) plasma cells to IgG+ cells were extraordinarily higher (mean 28%) than those in normal mucosa.DiscussionThese findings confirmed for the first time that autoantibodies against Dsg3 are mainly composed of IgG4 in oral PV and that the combined immunohistochemistry for Dsg3 and IgG4 can be a valuable aid in confirming a histopathological diagnosis of PV.
    Journal of Oral Pathology and Medicine 11/2014; · 1.87 Impact Factor
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    ABSTRACT: Milk fat globule-epidermal growth factor (EGF)-factor VIII (MFG-E8) is a secreted glycoprotein that promotes clearance of apoptotic cells by bridging phosphatidylserine on apoptotic cells and integrin αvβ3/5 on phagocytes. High expression of MFG-E8 has been reported in various types of cancer in humans. Apoptotic figures are frequently found in the surgical samples of oral squamous cell carcinoma (SCC) and carcinoma in situ, and we have often observed apoptotic carcinoma cells engulfed by macrophages or even by neighboring carcinoma cells. Thus we hypothesized that MFG-E8 might promote engulfment of apoptotic carcinoma cells by living carcinoma cells and that MFG-E8 expressed by carcinoma cells could contribute to tumor progression. The aim of this study was to elucidate the biological role of MFG-E8 in oral SCC. Fifty-three surgical specimens of oral SCC were used for immunohistochemistry for MFG-E8, and the expression profiles were correlated with clinicopathological properties. Also, we examined the MFG-E8 expression patterns and functions using three human oral SCC cell lines. Most of the cases had MFG-E8-positive SCC cells, and the expression of MFG-E8 was correlated with such clinicopathological features as tumor size, pathological stage, locoregional recurrence, scattering invasion pattern, and SCC cell figures engulfing apoptotic SCC cells. The MFG-E8 staining was enhanced in apoptotic SCC cells, some of which were apparently engulfed by the neighboring SCC cells. ZK-1 cells showed high MFG-E8 expression, and its localization was found in the cytoplasm and the cell surface. Transient MFG-E8 knockdown by siRNA in ZK-1 decreased cell proliferation and invasiveness and increased cell death. Thus we have demonstrated that MFG-E8 promotes tumor progression in oral SCC and that it might be involved in the clearance of apoptotic SCC cells by living SCC cells.Laboratory Investigation advance online publication, 29 September 2014; doi:10.1038/labinvest.2014.108.
    Laboratory Investigation 09/2014; 94(11). · 3.83 Impact Factor
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    ABSTRACT: We report a rare case of radiation-induced undifferentiated high-grade pleomorphic sarcoma (UPS) (malignant fibrous histiocytoma, MFH) in the right mandible of a 44-year-old woman. The patient had suffered from osteomyelitis of the same region of the mandible for several years, which was considered to be due to radiotherapy for a malignant lymphoma in her right neck 19 years before. The tumor appeared as an exophytic and invasive growth in the molar region of the mandible. Histopathologically, the tumor consisted of an interlacing proliferation of vimentin-immunopositive spindle-shaped fibroblastic cells with bizarre nuclei with high Ki-67 labeling scores, and tumor cells showed storiform patterns mixed with pleomorphic cells. Taking the history of radiation into consideration, we diagnosed the lesion as radiation-induced UPS. Including the present case, there have been only 14 documented cases of radiation-induced UPS in the jawbone, and this is the first case arising in the follow-up period of long-standing osteomyelitis.
    Pathology - Research and Practice 07/2014; · 1.56 Impact Factor
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    ABSTRACT: Background. Local recurrence remains a challenging clinical issue for the treatment of oral squamous cell carcinoma (SCC). We analyzed retrospectively how effective the frozen section technique (FS) was against recurrences of oral SCC. Methods. We screened 343 surgical samples from 236 patients who had oral SCC, carcinoma in situ (CIS), or epithelial dysplasia, and we followed up their clinical outcomes for at least 5 years. Histopathological states of surgical margins were compared between FS and surgical materials in relapse and relapse-free groups, respectively. Results. Among the 236 patients, 191 were classified into the relapse-free group, and 45 into the relapse group. FS was more frequently performed in the relapse-free group (128/191) than in the relapse group (83/152). Histopathologically, moderate dysplasia or CIS (borderline malignancies) and SCC were recognized in 55 samples of the relapse-free group and in 57 of the relapse group. For those surgical margins with borderline malignancies, additional incisions were performed in 38 of the 55 relapse-free cases, which reduced to 20 from the 38 margins with borderline malignancies (47.4% reduction), and in 39 of the 57 relapse cases, which reduced to only 3 of 39 (7.7% reduction). Conclusions. The intraoperative assessment of surgical margins by FS is essential in preventing recurrences of oral mucosal malignancies.
    BioMed Research International 06/2014; 2014:823968. · 2.71 Impact Factor
    This article is viewable in ResearchGate's enriched format
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    ABSTRACT: We have reported that neutrophilic infiltration was associated with round-shaped dyskeratosis foci, a kind of keratin pearl, of oral carcinoma in situ and that those inflammatory cells are recruited from intra-epithelially entrapped blood vessels. Based on these lines of evidence, we have formulated a hypothesis that keratin pearls are terminally degraded by neutrophils. To confirm this hypothesis, we investigated immunohistochemically stepwise degradation of keratin pearls in oral squamous cell carcinoma (SCC) to clarify any other type scavenger cells in addition to neutrophils are involved in this particular degradation process.
    Journal of Oral Pathology and Medicine 06/2014; · 1.87 Impact Factor
  • Takashi Saku
    Journal of Oral and Maxillofacial Surgery, Medicine, and Pathology. 04/2014;
  • Takashi Saku
    Journal of Oral and Maxillofacial Surgery, Medicine, and Pathology. 04/2014;
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    ABSTRACT: Background We have demonstrated the induction of perlecan-rich stroma of oral squamous cell carcinoma (SCC) on and after its start of invasion. However, it remains unknown how such a neoplastic stroma is actually arranged in tumor tissues.Methods To this end, tissue microarray samples, in which keratin and perlecan were contrastively labeled by immunohistochemistry, were three-dimensionally analyzed using digital images and image analysis software to demonstrate the relationship between SCC foci and the perlecan-positive stromal space or that between carcinoma in situ (CIS) and invasive SCC foci.ResultsThe three-dimensional (3D) reconstruction demonstrated three kinds of perlecan profiles for inside (I) and outside (O) areas of the carcinoma cell focus: mode 1, I+/O−; mode 2, I+/O+; and mode 3, I−/O+. Mode 1 was seen in CIS as well as SCC tumor massifs in the surface part. Mode 2 was seen in small SCC foci, which seemed isolated in 2D sections but were mostly continuous with the tumor massif in 3D reconstructions. Mode 3 was limited to small SCC foci, which were truly segregated from the tumor massif.Conclusions The results indicated that the 2D SCC focus isolation could not be regarded as invasion but that the SCC foci surrounded by perlecan-positive stroma (modes 2 and 3) could be regarded as a more objective measure for invasion of SCC. This is the first 3D tissue-level demonstration of the neoplastic stroma space induced with oral SCC invasion, the presence of which we have predicted based on our previous 2D and tissue culture evidence.
    Journal of Oral Pathology and Medicine 04/2014; · 1.87 Impact Factor
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    ABSTRACT: Periodontitis involves periodontal tissue destruction and is associated with chronic inflammation and ageing. Periodontitis has recently been recognised as a risk factor for Alzheimer's disease (AD). We showed upregulation of molecules in the AD pathway including amyloid beta (A4) precursor protein (APP), a key gene in AD, interleukin-1 beta (IL-1β), and complement component 1 (q subcomponent, A chain) (C1QA) in periodontitis compared to healthy tissues. Here, we quantitatively analysed the expression levels of APP, IL-1β, and C1QA and determined the localisation of APP in gingival tissues. Fourteen chronic periodontitis patients and 14 healthy participants were enrolled. Six samples of total RNA from two distinct sites of healthy and periodontitis-affected gingival tissues from three randomly selected patients were used for microarray analyses, and significant biological pathways in periodontitis were identified. Differential gene expression of APP, IL-1β, and C1QA, which belong to the AD pathway, were analysed with quantitative reverse transcription real-time polymerase chain reaction (qRT-PCR) using samples from these 14 chronic periodontitis patients and 14 healthy controls. APP localisation was analysed with immunohistochemistry. APP, IL-1β, and C1QA mRNA levels were significantly upregulated in periodontitis-affected gingival tissues. APP was mainly localised in macrophages in gingival connective tissues underneath the epithelial layers. An association between AD and periodontitis was detected with microarray and computer-aided data mining analyses. qRT-PCR identified differential gene expression in periodontitis-affected gingival tissue that may be related to AD pathogenesis. Elevated APP, IL-1β, and C1QA transcripts and APP-expressing macrophages in periodontitis-affected gingival tissues were observed, suggesting a relationship between periodontitis and AD pathogenesis.
    Archives of oral biology 03/2014; 59(6):586-594. · 1.65 Impact Factor
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    ABSTRACT: The aim of this study was to demonstrate the presence of intraepithelial stroma represented by extracellular matrix (ECM) deposits in the junctional epithelium to clarify its function as a scaffold for leukocyte migration through epithelial cells. Twenty-three biopsy specimens from the gingiva including the junctional epithelium were examined to determine comparative protein and gene level expression profiles for keratin and ECM molecules between the junctional epithelium and the gingival epithelium using immunohistochemistry and in situ hybridization. Intraepithelial leukocyte types and frequencies were also determined and compared between the junctional and gingival epithelia. In the junctional epithelium, which was positive for keratin 19, perlecan was strongly deposited in intercellular space of the whole epithelial layer, while it was faintly positive around the parabasal layer of the gingival epithelium. Perlecan mRNA signals were enhanced to a greater degree in both epithelial and inflammatory cells within the junctional epithelium. In the junctional epithelium, greater numbers of neutrophils and macrophages were found as compared with the gingival epithelium. Our results showed that perlecan is the primary ECM molecule comprising intraepithelial stroma of the junctional epithelium, in which leukocytes may migrate on ECM scaffolds in intercellular space toward the surface of the gingival sulci or pockets.
    Histochemie 02/2014; 142(3). · 2.93 Impact Factor
  • Takashi Saku
    Journal of Oral and Maxillofacial Surgery, Medicine, and Pathology. 01/2014;
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    ABSTRACT: Hybrid odontogenic tumors including 2 or more different histologic types have been documented, but their occurrences are not very common. We present a case of hybrid odontogenic tumor composed of ameloblastoma and adenomatoid odontogenic tumor (AOT) arising in the mandibular molar region of a 31-year-old Japanese woman who had a history of familial adenomatous polyposis. The tumor, measuring 10 mm in diameter, was surgically removed from the alveolar bone. Histopathologically, the tumor consisted of both follicular and plexiform types of ameloblastoma in which multiple and smaller foci of AOT were intermingled. There have been 3 reported cases of hybrid ameloblastoma and AOT, all of which presented unicystic types as ameloblastoma components. This, however, is the first report of a hybrid tumor containing an authentic solid-type ameloblastoma compartment and an AOT compartment in a patient with a background of familial adenomatous polyposis.
    Oral surgery, oral medicine, oral pathology and oral radiology. 11/2013;
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    ABSTRACT: Keratocystic odontogenic tumor (KCOT), a developmental jaw cyst previously referred to as odontogenic keratocyst (OKC), typically arises in the jawbone. In this article, however, we report a case of KCOT located within the temporalis muscle. We compared its immunohistochemical profiles with those of authentic jaw KCOT, orthokeratinized odontogenic cyst, and epidermoid cyst in order to consider whether a soft tissue counterpart of KCOT could be a separate disease entity. The patient was a 46-year-old man with a well-defined cystic lesion within the left temporalis muscle. On computed tomographic images, the lesion was recognized as a cystic lesion, although KCOT was not included in the clinical differential diagnoses. The location of the lesion was not within bone but, rather, within the temporalis muscle that was attached to the jawbones. Our review of the literature has disclosed more than 20 peripheral KCOT cases of the oral mucosa and more than 10 cases of the skin, but only 1 case arising in muscle. Immunohistochemical investigation of the present intramuscular case reveals KCOT-characteristic profiles distinct from the other 3 types of cysts investigated. The results indicate that KCOT-like lesions can arise within soft tissues, although use of the term odontogenic might seem inappropriate in those cases.
    Human pathology 10/2013; · 2.81 Impact Factor
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    ABSTRACT: To examine the histopathological characteristics of inflammatory lesions containing Actinomyces based on DNA sequencing. Furthermore, case reports of actinomycosis in the maxillofacial region are summarized by a review of the literature. The study comprised 12 cases of inflammatory lesions containing Actinomyces as diagnosed by DNA analysis. The average age of the subjects was 59 ± 15 years (6 males; 6 females). The distribution of causative bacteria was: Actinomyces israelii in 9 cases, Actinomyces gerencseriae in 2 cases, and Actinomyces naeslundii in 1 case. Four cases diagnosed by DNA sequencing were positive for "Druse," a known morphological diagnostic characteristic of actinomycosis, and 8 cases lacked typical colony formation. DNA analysis using paraffin-embedded samples is effective for both early and accurate diagnosis of oral lesions containing Actinomyces.
    Oral surgery, oral medicine, oral pathology and oral radiology. 10/2013; 116(4):485-91.
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    ABSTRACT: IL-17RA, a member of the interleukin (IL)-17 receptor family, is a single membrane-spanning protein that ubiquitously expressed on the cell surface. IL-17RA transduces IL-17A, IL-17F, and IL-17A/F heterodimer-mediated signals by forming a complex with IL-17RC, and also signals the IL-17E (also known as IL-25) response in combination with IL-17RB (also known as IL-25R). Previously, soluble isoforms of human IL-17RC and IL-17RB have been reported, but the existence of a soluble isoform of human IL-17RA has remained unclear. Here, we report the identification of a soluble isoform of human IL-17RA at the mRNA and protein levels. Reverse transcribed PCR experiments showed that the IL-17RA variant is generated by spliced out of exon 11 encoding the transmembrane region in a variety of human tissues. The soluble IL-17RA isoform was detected in the culture media of human cell lines by Western blotting. The existence of the soluble IL-17RA isoform sheds new light on the regulation of IL-17RA mediated responses.
    Cytokine 09/2013; · 2.87 Impact Factor
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    ABSTRACT: Objective: Adenoid cystic carcinoma (ACC) is histopathologically characterized by cribriform structures which are composed of two types of luminal spaces. One is considered to be true ductal and the other pseudocystic. We have demonstrated that the pseudocystic space was generated by an excessive deposition of perlecan produced by ACC cells and that the proliferation of ACC cells was regulated by these perlecan. But, it has been unknown which receptors are responsible for perlecan signaling. In the present study, we examined immunohistochemical distribution modes of two perlecan receptors, α-dystroglycan and integrin β1, in comparison with perlecan and some other related molecules Method: Surgical specimens of 11 cases of adenoid cystic carcinoma were examined by immunohistochemistry for perlecan, α-dystroglycan, integrin β1, Ki-67, CK19, calponin, and S-100 protein, using formalin fixed paraffin sections and the Envision system. Result: Flat tumor cells, surrounding the pseudocystic structures, were positive for α-dystroglycan . However, tumor cells forming true ductal structures, which were revealed by CK19 positivity, showed specialized staining intensities for α-dystroglycan. On the other hand, integrin β1 was strongly positive in peripheral cells of tumor nests and also the innermost cells forming pseudocystic structures. Ki-67 was mostly localized in the peripheral cells of tumor nests. Conclusion: The different immunohistochemical distribution of α-dystroglycan and integrin β1, suggested their different functional aspects after capturing perlecan signals.
    IADR Asia/Pacific Region (APR) Regional Meeting and Co-Annual Scientific Meeting of IADR Divisions 2013; 08/2013
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    ABSTRACT: A case of solitary central neurofibroma of the mandible arising in a 70-year-old man is reported. The patient had a radiolucent lesion, measuring 16 mm in diameter, with central radiopaque freckles in the right incisor–canine region of the mandible, which was discovered incidentally during routine dental check-up. The lesion was persisted for 10 years without any symptoms or complication. It was clinically diagnosed as benign tumor and surgically removed under general anesthesia. Histologically, the removed tumor was relatively well demarcated and composed of a sparse proliferation of elongated spindleshaped cells with wavy nuclei in loosely textured connective tissue stroma, which was associated with bone formation. Clinicopathological features of central neurofibroma of the jaw bone are reviewed from the literature. This is the first report of central neurofibroma arising in the anterior part of the mandible.
    Journal of Oral and Maxillofacial Surgery, Medicine, and Pathology. 07/2013;

Publication Stats

2k Citations
295.71 Total Impact Points


  • 1994–2014
    • Niigata University
      • • Department of Tissue Regeneration and Reconstruction
      • • Division of Oral Pathology
      • • Division of Oral and Maxillofacial Radiology
      • • Department of Pathology
      • • Division of Oral and Maxillofacial Surgery
      Niahi-niigata, Niigata, Japan
  • 2011
    • University of Aberdeen
      Aberdeen, Scotland, United Kingdom
  • 2009
    • University of Jordan
      • Faculty of Dentistry
      Amman, Amman, Jordan
    • King Faisal University
      Al Hadā, Makkah, Saudi Arabia
    • University of Peradeniya
      • Department of Oral Pathology
      Kandy, Central Province, Sri Lanka
  • 2004
    • Sichuan University
      • Department of Pathology
      Chengdu, Sichuan Sheng, China
  • 2002
    • The University of Tokyo
      • Department of Biotechnology
      Tokyo, Tokyo-to, Japan
  • 1997
    • Radiation Effects Research Foundation
      Hirosima, Hiroshima, Japan
  • 1992
    • Tokyo Medical and Dental University
      Edo, Tōkyō, Japan
  • 1984–1990
    • Nagasaki University
      • Department of Pathology
      Nagasaki, Nagasaki, Japan