Hiroyuki Mitomi
Dokkyo Medical University
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Featured researches published by Hiroyuki Mitomi.
American Journal of Pathology | 2000
Yasuo Takano; Yo Kato; Paul J. van Diest; Mitsunobu Masuda; Hiroyuki Mitomi; Isao Okayasu
G1 cyclins and cyclin-dependent kinase (CDK) complexes play important roles in G1 cell cycle transition, and their overexpression is implicated for neoplasia. The p27 protein (p27) negatively regulates G1 progression by binding to G1 cyclins/CDK complexes and inhibits their activity, resulting in inhibition of entry to the cell cycle. We investigated overexpression of cyclin D1 (CCND1), cyclin D2 (CCND2), cyclin E (CCNE), CDK2, and CDK4, in addition to p27, in 260 gastric cancer cases on the basis of Western blots, reverse transcriptase-polymerase chain reaction Southern blots, and immunohistochemistry to clarify the roles of these proteins in tumor progression and prognosis. Examination of 20 cases of fresh cancer and matched normal tissues demonstrated a clear tendency for increased mRNA synthesis to be more frequent than expected from protein levels, and a direct correlation between p27 protein and mRNA was not found. Immunohistochemistry demonstrated 21. 5%, 34.2%, 30.4%, 44.2%, and 48.0% positivity for CCND1, CCND2, CCNE, CDK2, and CDK4, respectively, in the 260 gastric cancer cases. Overexpression of CCND2 and CDK4 significantly correlated with tumor progression. Moreover, CCND2 cytoplasmic staining (26.2%) appeared to be strictly linked with progression, whereas nuclear staining (7. 8%) demonstrated an inverse correlation. Survival curves showed CCND2 (especially cytoplasmic staining) and CDK4 positivity to be associated with a poor prognosis and CCNE positivity with a better prognosis. Tumors with high p27 labeling indices (LIs) were well differentiated, with low levels of invasion and lymph node metastasis. p27-negative cases (37.3%) demonstrated a poor prognosis. Multivariate analysis revealed positivity for CCND2 and negativity for p27 to be independent prognostic factors. There were no direct links among CCND2, CCNE, CDK4, and p27. The results indicate that CCND2 cytoplasmic localization might reflect an important physiological role in tumor progression, whereas CCNE overexpression correlates with differentiation and a good prognosis, possibly because of accumulation of inactive forms of CCNE-CDK2 complexes. Loss of p27 caused by degradation activity may affect tumor cell growth in the presence of an altered extracellular matrix, facilitating metastasis. Cell-cycle-regulatory proteins appear to work independently.
Gastrointestinal Endoscopy | 2002
Satoshi Tanabe; Wasaburo Koizumi; Hiroyuki Mitomi; Hisao Nakai; Satoshi Murakami; Shizuka Nagaba; Mitsuhiro Kida; Masahito Oida; Katsunori Saigenji
BACKGROUND Endoscopic mucosal resection is an established treatment option for early stage gastric cancer. However, several problems with endoscopic mucosal resection remain to be solved, such as appropriate treatment for recurrence and incomplete tumor resection. The outcome for patients undergoing endoscopic aspiration mucosectomy (endoscopic mucosal resection) by a modification of the cap-fitted technique was evaluated retrospectively to determine factors associated with complete resection and tumor recurrence. METHODS Endoscopic mucosal resection was performed in 106 patients with early stage gastric cancers up to 20 mm in diameter that were well or moderately differentiated adenocarcinoma. All were superficial lesions without ulceration, distinct signs of submucosal invasion, or a poorly demarcated border. En bloc (tumors <10 mm in diameter) or piecemeal (tumors 10-20 mm in diameter) resection was performed. Follow-up endoscopy was performed at 2, 6, 12, 18, and 24 months and thereafter once per year. Outcome and factors associated with complete resection and tumor recurrence were assessed retrospectively. RESULTS Sixty-eight patients (64%) underwent en bloc resection and 38 (36%) piecemeal resection. The mean longest dimension (SD) of the resected lesions was significantly greater after piecemeal resection (12.3 [4.0] mm) than after en bloc resection (7.6 [4.0] mm; p < 0.01). In patients with tumors completely resected, there was no recurrence after either en bloc or piecemeal resection. Six of 8 patients found to have submucosal invasion after endoscopic mucosal resection underwent surgery. Patients with incompletely resected intramucosal lesions underwent additional endoscopic treatment. Cancer recurred in 3 patients (2.8%), all of whom had lesions measuring more than 15 mm in diameter. CONCLUSIONS Endoscopic mucosal resection is safe and useful for the management of early stage gastric cancer. Further improvement in outcome requires more accurate preoperative diagnosis and postoperative histopathologic evaluation. Patients with incompletely resected lesions should undergo aggressive additional treatment.
Gastrointestinal Endoscopy | 1999
Satoshi Tanabe; Wasaburo Koizumi; Mikio Kokutou; Hiroshi Imaizumi; Keita Ishii; Mitsuhiro Kida; Yasushi Yokoyama; Masahito Ohida; Katsunori Saigenji; Hitoshi Shimao; Hiroyuki Mitomi
BACKGROUND Several techniques are available for the endoscopic treatment of gastric intramucosal cancers, but their advantages and disadvantages have not been adequately evaluated. We compared the therapeutic usefulness of endoscopic aspiration mucosectomy with that of strip biopsy. METHODS Between May 1995 and May 1997, we performed strip biopsy (May 1995 through February 1996) or endoscopic aspiration mucosectomy (March 1996 through May 1997) in a consecutive series of patients with intestinal-type intramucosal cancer. Parameters of assessment included the following: size of removed specimens, en bloc resection rate, time required for resection, duration of hospitalization, and complications. RESULTS Forty-nine patients with gastric intramucosal cancers underwent endoscopic aspiration mucosectomy and 44 underwent strip biopsy. The two groups were similar with respect to age, gender, and lesion macroscopic appearance, size, and site. The mean longest diameter of the resected specimens was significantly greater with endoscopic aspiration mucosectomy (20.3 +/- 3.4 mm) than with strip biopsy (15. 8 +/- 4.4 mm) (p < 0.001). The rate of en bloc resection (resection of an entire lesion in one procedure) was significantly higher with endoscopic aspiration mucosectomy (61.2%, 30 of 49) than with strip biopsy (36.4%, 16 of 44) (p < 0.05). The number of specimens obtained by piecemeal resection was slightly, but not significantly, higher with strip biopsy (2.4 +/- 1.7) than with endoscopic aspiration mucosectomy (2.0 +/- 1.7). The time required for treatment was similar for each procedure. The duration of hospitalization was significantly shorter with endoscopic aspiration mucosectomy (12.8 +/- 5.3 days) than with strip biopsy (15.9 +/- 74 days) (p < 0.05). As for complications, the rate of bleeding was 20. 5% (9 of 44) with strip biopsy and 10.2% (5 of 49) with endoscopic aspiration mucosectomy; bleeding was controlled in all cases by treatment with a heater probe. CONCLUSIONS Endoscopic resection of large gastric intramucosal tumors is easier with endoscopic aspiration mucosectomy compared with strip biopsy. Endoscopic aspiration mucosectomy is a useful procedure for en bloc resection.
Diseases of The Colon & Rectum | 2008
Takatoshi Nakamura; Hiroyuki Mitomi; Hideki Kanazawa; Yasuo Ohkura; Masahiko Watanabe
PurposeHigh-risk patients with Stage II colon cancer may benefit from adjuvant chemotherapy, but they are difficult to identify. We assessed the value of tumor budding, defined as small clusters of undifferentiated cancer cells at invasive margins, as a predictor of outcomes in patients with Stage II colon cancer.MethodsWe studied a total of 200 patients with Stage II colon cancer who underwent curative surgery. With hematoxylin and eosin-stained specimens, the degree of tumor budding was classified as low-grade or high-grade. The survival rate of patients who had Stage II disease with low-grade or high-grade tumor budding was compared with that of 226 patients who had Stage III colon cancer.ResultsUnivariate analysis revealed that serosal surface involvement (P = 0.04) and tumor budding (P < 0.001) were significantly related to survival. Cumulative five- and ten-year survival rates differed significantly between patients with low-grade tumor budding (93.9 and 90.6 percent, respectively) and those with high-grade (73.9 and 67.8 percent, respectively). Survival rates did not differ significantly between patients with Stage II disease who had high-grade tumor budding and patients with Stage III disease. Cox’s regression analysis demonstrated that tumor budding (hazard ratio, 4.89; P < 0.001) and serosal surface involvement (hazard ratio, 2.561; P = 0.023) were independent prognostic factors. Liver (P < 0.001) and peritoneal (P = 0.003) metastases were more frequent in the patients with high-grade tumor budding than in those with low-grade.ConclusionsTumor budding is useful for prognosis and identifying patients with Stage II colon cancer who have a high risk of disease recurrence after curative surgery.
Colorectal Disease | 2007
Hideki Kanazawa; Hiroyuki Mitomi; Y. Nishiyama; Ichiro Kishimoto; Naoshi Fukui; Takatoshi Nakamura; Masahiko Watanabe
Objective Tumour budding, defined as small clusters of undifferentiated cancer cells at invasive margins, has been shown to reflect biologic aggressiveness of colorectal cancers. We therefore examined the prognostic significance of tumour budding in patients with colorectal carcinoma, particularly focusing on comparisons with other clinicopathological findings.
Histopathology | 2012
Giacomo Puppa; Carlo Senore; Kieran Sheahan; Michael Vieth; Alessandro Lugli; Inti Zlobec; Sara Pecori; Lai Mun Wang; Cord Langner; Hiroyuki Mitomi; Takatoshi Nakamura; Masahiko Watanabe; Hideki Ueno; Jacques Chasle; Stephen A Conley; Paulette Herlin; Gregory Y. Lauwers; Mauro Risio
Puppa G, Senore C, Sheahan K, Vieth M, Lugli A, Zlobec I, Pecori S, Wang L M, Langner C, Mitomi H, Nakamura T, Watanabe M, Ueno H, Chasle J, Conley S A, Herlin P, Lauwers G Y & Risio M (2012) Histopathology 61, 562–575
Arthritis & Rheumatism | 2008
Naoshi Fukui; Yasuko Ikeda; Toshiyuki Ohnuki; Nobuho Tanaka; Atsuhiko Hikita; Hiroyuki Mitomi; Toshihito Mori; Takuo Juji; Yozo Katsuragawa; Seizo Yamamoto; Motoji Sawabe; Shoji Yamane; Ryuji Suzuki; Linda J. Sandell; Takahiro Ochi
OBJECTIVE To determine the change in metabolic activity of chondrocytes in osteoarthritic (OA) cartilage, considering regional difference and degree of cartilage degeneration. METHODS OA cartilage was obtained from knee joints with end-stage OA, at both macroscopically intact areas and areas with various degrees of cartilage degeneration. Control cartilage was obtained from age-matched donors. Using laser capture microdissection, cartilage samples were separated into superficial, middle, and deep zones, and gene expression was compared quantitatively in the respective zones between OA and control cartilage. RESULTS In OA cartilage, gene expression changed markedly with the site. The expression of cartilage matrix genes was highly enhanced in macroscopically intact areas, but the enhancement was less obvious in the degenerated areas, especially in the upper regions. In contrast, in those regions, the expression of type III collagen and fibronectin was most enhanced, suggesting that chondrocytes underwent a phenotypic change there. Within OA cartilage, the expression of cartilage matrix genes was significantly correlated with SOX9 expression, but not with SOX5 or SOX6 expression. In OA cartilage, the strongest correlation was observed between the expression of type III collagen and fibronectin, suggesting the presence of a certain link(s) between their expression. CONCLUSION The results of this study revealed a comprehensive view of the metabolic change of the chondrocytes in OA cartilage. The change of gene expression profile was most obvious in the upper region of the degenerated cartilage. The altered gene expression at that region may be responsible for the loss of cartilage matrix associated with OA.
Diseases of The Colon & Rectum | 2004
Miwa Sada; Masahiro Igarashi; Shigeru Yoshizawa; Kiyonori Kobayashi; Tomoe Katsumata; Katsunori Saigenji; Yoshimasa Otani; Isao Okayasu; Hiroyuki Mitomi
PURPOSEThe aim of this study was to investigate detection of dysplasia or colitic cancer with ulcerative colitis by use of magnifying endoscopic observation.METHODSFrom 1986 through 2000, ulcerative colitis was diagnosed and treated in 886 patients at Kitasato University East Hospital. Of the total, we studied 25 patients in depth: 14 who had dysplasia alone, 5 in whom cancer was diagnosed during follow-up after the detection of dysplasia, and 6 who had colitic cancer.RESULTSDysplasia was detected in 11 (3.2 percent) of 345 patients with extensive colitis and in 8 (3.7 percent) of 217 with left-sided colitis. Colorectal cancer was diagnosed in nine patients (2.6 percent) with extensive colitis and in two (0.9 percent) with left-sided colitis. Neither dysplasia nor colitic cancer was found in patients with proctitis-type colitis. Endoscopically, dysplasia and early cancer were characterized by granular or nodular protruding mucosa or by lowly protruding or flat mucosa, often associated with redness. Dye-spraying endoscopy was useful for detection. Magnifying endoscopy of ten regions of dysplasia (7 patients) and five early cancers (4 patients) showed IIIS to IIIL type pits or IV type pits. Biopsy of sites showing tumorous pits on magnifying endoscopy revealed dysplasia and early cancer. Observation of the pit pattern was found to be diagnostically useful.CONCLUSIONSDye spraying and magnifying endoscopy are useful for the detection, targeted biopsy, and diagnosis of dysplasia and colitic cancer in patients with ulcerative colitis.
The Journal of Pathology | 2003
Tsutomu Yoshida; Tetuo Mikami; Hiroyuki Mitomi; Isao Okayasu
In long‐standing ulcerative colitis (UC), p53 mutations have been shown to occur by indirect detection methods such as PCR–SSCP. To clarify whether p53 gene mutations are early events in UC‐associated neoplasia and to analyse clonality within dysplasia‐associated lesions or masses (DALMs), the entire coding region of the p53 gene was analysed in DNA of microdissected single crypts by the polymerase chain reaction (PCR)–direct sequencing method. With a novel microdissection method using serial histological sections, the p53 gene (exons 2–11) was analysed in a total of 11 regenerative crypts and 76 single crypts within seven DALMs selected from three colectomy specimens of long‐standing UC patients. Although p53 point mutations were found in at least one crypt in each DALM, heterogeneity in terms of the presence and the type of genetic change was marked, except in one carcinoma. As early events, p53 gene mutations were apparent even in some regenerative crypts (8/12 crypts). Some were of silent type. Altered p53 protein expression was confirmed in only 14/32 mutated crypts and was also evident in 24 other non‐mutated examples by immunostaining of serial sections. Polyclonal p53 gene mutations were found in regenerative (REG) crypts and low‐grade dysplasia (LGD), but monoclonal changes were noted in high‐grade dysplasia (HGD) or carcinoma (Ca) in long‐standing UC. At the single crypt level, however, p53 point mutations were not always linked to p53 overexpression, indicating a discrepancy between gene alteration and protein accumulation in LGD. Copyright
Gait & Posture | 2009
Kohei Nakajima; Wataru Kakihana; Takumi Nakagawa; Hiroyuki Mitomi; Atsuhiko Hikita; Ryuji Suzuki; Masami Akai; Tsutomu Iwaya; Kozo Nakamura; Naoshi Fukui
In order to examine if the addition of an arch support could improve the biomechanical effect of the laterally wedged insole, three-dimensional gait analysis was performed on 20 healthy volunteers. Kinetic and kinematic parameters at the knee and subtalar joints were compared among the following four types of insoles; a 5-mm thick flat insole, a flat insole with an arch support (AS), a 6 degrees inclined laterally wedged insole (LW), and a laterally wedged insole with an arch support (LWAS). The knee adduction moment averaged for the entire stance phase was reduced by the use of LW and LWAS by 7.7% and 13.3%, respectively, from that with FLAT. The difference in knee adduction moment between LW and LWAS was most obvious in the late stance, which was ascribed to the difference in the progression angle between those insoles. The analyses also revealed that LW tended to increase step width, and that such an increase was completely eliminated by the addition of an arch support to LW. This reduction of step width could be another mechanism for the further reduction of the moment with LWAS. The analyses of biomechanical parameters at the subtalar joints suggested that LWAS allowed the subject to walk in a more natural manner, while exerting greater biomechanical effects than LW. Thus, the addition of an arch support to the laterally wedged insole reduced knee adduction moment more efficiently, possibly through the elimination of potential negative effects of the laterally wedged insole.