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Dive into the research topics where Yoshiki Mikami is active.

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Featured researches published by Yoshiki Mikami.


Journal of Magnetic Resonance Imaging | 2007

Diffusion‐weighted MR imaging of uterine endometrial cancer

Ken Tamai; Takashi Koyama; Tsuneo Saga; Shigeaki Umeoka; Yoshiki Mikami; Shingo Fujii; Kaori Togashi

To determine the feasibility of diffusion‐weighted (DW) MRI of uterine endometrial cancer and to investigate whether the apparent diffusion coefficient (ADC) values of endometrial cancer differ from those of normal endometrium and whether they differ according to the histologic grade of the tumor.


The American Journal of Surgical Pathology | 2007

Gastric morphology and immunophenotype predict poor outcome in mucinous adenocarcinoma of the uterine cervix

Atsumi Kojima; Yoshiki Mikami; Tamotsu Sudo; Satoshi Yamaguchi; Yasuki Kusanagi; Masaharu Ito; Ryuichiro Nishimura

Endocervical-type mucinous adenocarcinoma (ECA) of the uterine cervix is defined as a tumor composed of cells resembling those of the endocervical glands, but recent studies have demonstrated that a minority of ECAs displays a gastric immunophenotype. The aim of this study was to assess the significance of the gastric phenotype. Fifty-three cases of mucinous adenocarcinoma of the uterine cervix (37 FIGO stage IB, 4 stage IIA, and 12 stage IIB) were reviewed and reevaluated using a newly established morphologic criteria for distinguishing gastric type adenocarcinoma, which was defined as a tumor showing clear and/or pale eosinophilic and voluminous cytoplasm, with distinct cell borders. The results were correlated with gastric immunophenotype, determined by HIK1083 and MUC6 immunostaining, and patient outcome. Following the current World Health Organization scheme (2003), 47 tumors (89%) were classified as ECA, 1 (2%) as intestinal type, 1 (2%) as mixed endocervical and intestinal type, and 4 (8%) as minimal deviation adenocarcinoma. Twelve of 47 (26%) ECAs and all 4 minimal deviation adenocarcinomas, reclassified as gastric type using the novel criteria, were frequently positive for HIK1083 with a rate of 75% (12/16), whereas only 11% (4/37) of nongastric tumors were positive. There was no significant difference in MUC6 reactivity between gastric and nongastric type tumors (31%, 5/16 vs. 16%, 6/37; P=0.4). Patients with gastric-type adenocarcinomas had a significantly decreased 5-year disease-specific survival rate (30 vs. 77%; P<0.0001), and the gastric type morphology was related to a significant risk for disease recurrence compared with the nongastric type (P=0.001; HR, 4.5; 95% confidence interval, 1.42-14.2). HIK1083-positivity was also related to decreased 5-year disease-specific survival rate (38% vs. 74%; P<0.005). Mucinous adenocarcinoma of the uterine cervix with gastric immunophenotype can be a distinct morphologic variant showing an aggressive clinical course.


Clinical Cancer Research | 2008

Secreted CXCL1 Is a Potential Mediator and Marker of the Tumor Invasion of Bladder Cancer

Hiroaki Kawanishi; Yoshiyuki Matsui; Masaaki Ito; Jun Watanabe; Takeshi Takahashi; Koji Nishizawa; Hiroyuki Nishiyama; Toshiyuki Kamoto; Yoshiki Mikami; Yoshinori Tanaka; Giman Jung; Hideo Akiyama; Hitoshi Nobumasa; Parry Guilford; Anthony E. Reeve; Yasushi Okuno; Gozoh Tsujimoto; Eijiro Nakamura; Osamu Ogawa

Purpose: The purpose of this study was to identify proteins that are potentially involved in the tumor invasion of bladder cancer. Experimental Design: We searched for the candidate proteins by comparing the profiles of secreted proteins among the poorly invasive human bladder carcinoma cell line RT112 and the highly invasive cell line T24. The proteins isolated from cell culture supernatants were identified by shotgun proteomics. We found that CXCL1 is related to the tumor invasion of bladder cancer cells. We also evaluated whether the amount of the chemokine CXCL1 in the urine would be a potential marker for predicting the existence of invasive bladder tumors. Results: Higher amount of CXCL1 was secreted from highly invasive bladder carcinoma cell lines and this chemokine modulated the invasive ability of those cells in vitro. It was revealed that CXCL1 regulated the expression of matrix metalloproteinase-13 in vitro and higher expression of CXCL1 was associated with higher pathologic stages in bladder cancer in vivo. We also showed that urinary CXCL1 levels were significantly higher in patients with invasive bladder cancer (pT1-4) than those with noninvasive pTa tumors (P = 0.0028) and normal control (P < 0.0001). Finally, it was shown that CXCL1 was an independent factor for predicting the bladder cancer with invasive phenotype. Conclusions: Our results suggest that CXCL1 modulates the invasive abilities of bladder cancer cells and this chemokine may be a potential candidate of urinary biomarker for invasive bladder cancer and a possible therapeutic target for preventing tumor invasion.


Histopathology | 2001

Lobular endocervical glandular hyperplasia is a metaplastic process with a pyloric gland phenotype

Yoshiki Mikami; Sakae Hata; Jonathan Melamed; Keiichi Fujiwara; Toshiaki Manabe

Lobular endocervical glandular hyperplasia is a metaplastic process with a pyloric gland phenotype


American Journal of Pathology | 2010

Absence of High-Risk Human Papillomavirus (HPV) Detection in Endocervical Adenocarcinoma with Gastric Morphology and Phenotype

Yasuki Kusanagi; Atsumi Kojima; Yoshiki Mikami; Takako Kiyokawa; Tamotsu Sudo; Satoshi Yamaguchi; Ryuichiro Nishimura

A subset of endocervical-type mucinous adenocarcinomas (ACs) of the uterine cervix exhibit a gastric phenotype and morphology, as reported in cases of minimal deviation AC in which the presence of human papillomavirus (HPV) has been rarely detected. To investigate the HPV-independent pathway of carcinogenesis in cases of gastric-type AC, we investigated the common high-risk HPV (hr-HPV) status in 52 nonsquamous cell carcinomas, using a PCR-based typing method and immunohistochemistry of p16INK4a (a cyclin-dependent kinase inhibitor that is overexpressed in both cancerous and precancerous cervical tissue, making it an ideal biomarker for cervical cancer cases). Using novel morphological criteria, seven of 52 (13.5%) carcinomas were designated as gastric-type ACs, all of which were negative for both hr-HPV DNA and p16INK4a. Nongastric-type ACs were frequently positive for both hr-HPV DNA (90%, 28/31) and p16INK4a (94%, 29/31) with adenosquamous and neuroendocrine carcinomas demonstrating the presence of hr-HPV DNA in 86% (6/7) and 83% (5/6) of cases, respectively. In these two types of carcinoma, 86% (6/7) and 100% (6/6) were positive for p16INK4a, respectively. Our data suggests that gastric-type AC appears to represent an oncogenic hr-HPV-independent neoplasm and therefore is a potential pitfall of HPV DNA testing and vaccination.


Advances in Anatomic Pathology | 2013

Endocervical glandular lesions exhibiting gastric differentiation: an emerging spectrum of benign, premalignant, and malignant lesions.

Yoshiki Mikami; W. Glenn McCluggage

A variety of benign and malignant endocervical glandular lesions exhibiting gastric differentiation has been described in the past decade that has resulted in the concept of an important category of cervical adenocarcinoma which is unrelated to human papillomavirus (HPV). Both minimal deviation adenocarcinoma (MDA), also known as adenoma malignum, and the benign lesion lobular endocervical glandular hyperplasia (LEGH), have been known for some time to exhibit a gastric phenotype and immunophenotype (HIK1083 and/or MUC6 positive). Accumulated evidence suggests that a subset of LEGH (atypical LEGH) exhibits a degree of cytologic and/or architectural atypia which, in some cases, may be associated with and be a precursor of adenocarcinomas exhibiting gastric differentiation, including MDA. Gastric-type adenocarcinoma (GAS), a recently described subtype of cervical adenocarcinoma, is an emerging clinicopathologic entity. These neoplasms exhibit a spectrum of differentiation, including MDA as its very well-differentiated form, are unrelated to HPV, and exhibit aggressive clinical behavior. It is proposed that a LEGH-GAS sequence exists and, from a practical point of view, the development of optimal biomarkers is awaited to assist in early detection of GAS and atypical LEGH, as current HPV-targeted screening generally does not detect these lesions and strategies employing HPV vaccination will not prevent their occurrence. Pathologists should be familiar with the morphologic spectrum of these benign, premalignant, and malignant cervical glandular lesions exhibiting gastric differentiation. They are occasionally associated with Peutz-Jeghers syndrome or are a component of “synchronous mucinous metaplasia and neoplasia of the female genital tract.”


The American Journal of Surgical Pathology | 2008

Is lobular endocervical glandular hyperplasia a cancerous precursor of minimal deviation adenocarcinoma?: a comparative molecular-genetic and immunohistochemical study.

Shigeto Kawauchi; Tomoko Kusuda; Xu Ping Liu; Yutaka Suehiro; Tsunehisa Kaku; Yoshiki Mikami; Morishige Takeshita; Motonao Nakao; Yasuyo Chochi

Although lobular endocervical glandular hyperplasia (LEGH) was originally described as a distinct hyperplastic glandular lesion of the uterine cervix, recent studies have raised a question that LEGH may be a cancerous precursor of minimal deviation adenocarcinoma (MDA) and other mucinous adenocarcinomas (MACs) of the uterine cervix. In the present study, we studied LEGH, MDA, and MAC by using molecular-genetic and immunohistochemical methods for chromosomal imbalance, microsatellite instability, human papillomavirus (HPV) infection, and gastric pyloric-type mucin secretion to clarify their relationship. Comparative genomic hybridization revealed recurrent chromosomal imbalances, that is, gains of chromosome 3q and a loss of 1p, which were common to MDA and MAC, in 3 of 14 LEGHs analyzed (21%). LEGHs with chromosomal imbalances showed a degree of cellular atypia in the hyperplastic glandular epithelium. Dual-color fluorescence in situ hybridization confirmed a gain of chromosome 3 fragment in these cervical glandular lesions. HPV in situ hybridization revealed that high-risk HPV (types 16 and 18) was positive in over 80% of MACs, but negative in all LEGHs and MDAs examined. Microsatellite instability was rarely detected in these cervical glandular lesions. Our present study results demonstrated a molecular-genetic link between LEGH and cervical mucinous glandular malignancies including MDA and MAC, and are thought to support the hypothesis that a proportion of LEGHs are cancerous precursors of MDA and/or MAC.


Cancer Research | 2010

Identification of EP4 as a Potential Target for the Treatment of Castration-Resistant Prostate Cancer Using a Novel Xenograft Model

Naoki Terada; Yosuke Shimizu; Tomomi Kamba; Takahiro Inoue; Atsushi Maeno; Takashi Kobayashi; Eijiro Nakamura; Toshiyuki Kamoto; Toshiya Kanaji; Takayuki Maruyama; Yoshiki Mikami; Yoshinobu Toda; Toshiyuki Matsuoka; Yasushi Okuno; Gozoh Tsujimoto; Shuh Narumiya; Osamu Ogawa

More effective therapeutic approaches for castration-resistant prostate cancer (CRPC) are urgently needed, thus reinforcing the need to understand how prostate tumors progress to castration resistance. We have established a novel mouse xenograft model of prostate cancer, KUCaP-2, which expresses the wild-type androgen receptor (AR) and which produces the prostate-specific antigen (PSA). In this model, tumors regress soon after castration, but then reproducibly restore their ability to proliferate after 1 to 2 months without AR mutation, mimicking the clinical behavior of CRPC. In the present study, we used this model to identify novel therapeutic targets for CRPC. Evaluating tumor tissues at various stages by gene expression profiling, we discovered that the prostaglandin E receptor EP4 subtype (EP4) was significantly upregulated during progression to castration resistance. Immunohistochemical results of human prostate cancer tissues confirmed that EP4 expression was higher in CRPC compared with hormone-naïve prostate cancer. Ectopic overexpression of EP4 in LNCaP cells (LNCaP-EP4 cells) drove proliferation and PSA production in the absence of androgen supplementation in vitro and in vivo. Androgen-independent proliferation of LNCaP-EP4 cells was suppressed when AR expression was attenuated by RNA interference. Treatment of LNCaP-EP4 cells with a specific EP4 antagonist, ONO-AE3-208, decreased intracellular cyclic AMP levels, suppressed PSA production in vitro, and inhibited castration-resistant growth of LNCaP-EP4 or KUCaP-2 tumors in vivo. Our findings reveal that EP4 overexpression, via AR activation, supports an important mechanism for castration-resistant progression of prostate cancer. Furthermore, they prompt further evaluation of EP4 antagonists as a novel therapeutic modality to treat CRPC.


Modern Pathology | 2002

Expression of CD10 in malignant müllerian mixed tumors and adenosarcomas: An immunohistochemical study

Yoshiki Mikami; Sakae Hata; Takako Kiyokawa; Toshiaki Manabe

CD10 has been demonstrated to be positive in endometrial stromal sarcoma (ESS) and thus is useful in establishing the diagnosis, but its expression in malignant müllerian mixed tumor (MMMT) and müllerian adenosarcoma remains to be clarified. In this study, 12 cases of MMMT (9 uterine, 2 tubal, and 1 metastatic), 6 cases of müllerian adenosarcoma (three corporeal, two cervical, and one tubal), and 7 cases of primary uterine sarcomas had their tissues examined immunohistochemically for expression of CD10, desmin, myoglobin, α-smooth muscle actin (SMA), and cytokeratin. Of the primary uterine sarcomas, two were primary rhabdomyosarcomas (one cervical and one corporeal), two were ESSs, two were high-grade leiomyosarcomas, and one was a high-grade endometrial sarcoma. Sarcomatous components in all cases of MMMT and müllerian adenosarcoma, as well as all uterine sarcomas, were positive for CD10, showing moderate to marked staining intensity with varying distribution except in one MMMT, which showed weak and very focal staining. In four MMMTs, three adenosarcomas, and one rhabdomyosarcoma, myoglobin- and/or desmin-positive rhabdomyoblastic cells were positive for CD10. The immunoreactivity for CD10 showed the same distribution for α-SMA and myoglobin in three and two MMMTs, respectively. In five cases of MMMT, carcinomatous components were focally positive for CD10, and in two cases small populations of round or short spindle cells in sarcomatous components were positive for CD10, α-SMA, and cytokeratin (CAM5.2). These results indicate that CD10 expression is not restricted to ESS but can be positive in MMMT and müllerian adenosarcoma as well as in a variety of uterine tumors including high-grade leiomyosarcoma and rhabdomyosarcoma. CD10 expression might be one of the characteristics of müllerian system-derived neoplastic mesenchymal cells.


Journal of Cancer Research and Clinical Oncology | 2008

Microarray-based identification of CUB-domain containing protein 1 as a potential prognostic marker in conventional renal cell carcinoma.

Yasuo Awakura; Eijiro Nakamura; Takeshi Takahashi; Hirokazu Kotani; Yoshiki Mikami; Tadashi Kadowaki; Akira Myoumoto; Hideo Akiyama; Noriyuki Ito; Toshiyuki Kamoto; Toshiaki Manabe; Hitoshi Nobumasa; Gozoh Tsujimoto; Osamu Ogawa

PurposeRenal cell carcinoma (RCC) is characterized by a variable and unpredictable clinical course. Thus, accurate prediction of the prognosis is important in clinical settings. We conducted microarray-based study to identify a novel prognostic marker in conventional RCC.Patients and methodsThe present study included the patients surgically treated at Kyoto University Hospital. Gene expression profiling of 39 samples was carried out to select candidate prognostic markers. Quantitative real-time PCR of 65 samples confirmed the microarray experiment results. Finally, we evaluated the significance of potential markers at their protein expression level by immunohistochemically analyzing 230 conventional RCC patients.ResultsUsing expression profiling analysis, we identified 14 candidate genes whose expression levels predicted unfavorable disease-specific survival. Next, we examined the expression levels of nine candidate genes by quantitative real-time PCR and selected CUB-domain containing protein 1 (CDCP1) for further immunohistochemical analysis. Positive staining for CDCP1 inversely correlated with disease-specific and recurrence-free survivals. In multivariate analysis including clinical/pathological factors, CDCP1 staining was a significant predictor of disease-specific and recurrence-free survivals.ConclusionsWe identified CDCP1 as a potential prognostic marker for conventional RCC. Further studies might be required to confirm the prognostic value of CDCP1 and to understand its function in RCC progression.

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