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Featured researches published by Go Omura.


Cancer | 2013

Prognostic value of p16 expression and alcohol consumption in Japanese patients with oropharyngeal squamous cell carcinoma

Yuki Saito; Masafumi Yoshida; Tetsuo Ushiku; Go Omura; Yasuhiro Ebihara; Toshiyuki Shimono; Masashi Fukayama; Tatsuya Yamasoba; Takahiro Asakage

The prevalence and prognostic value of human papillomavirus‐related oropharyngeal squamous cell carcinoma (OPSCC) in Japan has not been evaluated.


Laryngoscope | 2014

Salvage surgery for local residual or recurrent pharyngeal cancer after radiotherapy or chemoradiotherapy

Go Omura; Yuki Saito; Mizuo Ando; Kenya Kobayashi; Yasuhiro Ebihara; Tatsuya Yamasoba; Takahiro Asakage

Local residual or recurrent pharyngeal cancer after definitive radiotherapy (RT) or chemoradiotherapy (CRT) is correlated to poor prognosis. We analyzed the efficacy of salvage surgery for patients with local residual or recurrent pharyngeal cancer after RT or CRT.


Japanese Journal of Clinical Oncology | 2015

Prognostic value of p16 expression irrespective of human papillomavirus status in patients with oropharyngeal carcinoma

Yuki Saito; Masafumi Yoshida; Go Omura; Kenya Kobayashi; Chisato Fujimoto; Mizuo Ando; Takashi Sakamoto; Takahiro Asakage; Tatsuya Yamasoba

OBJECTIVE In a previous study, we reported the value of p16 expression and alcohol consumption in oropharyngeal carcinoma in Japan. We now report the clinical significance of human papillomavirus status and p16 expression in oropharyngeal carcinoma in Japan. METHODS Over a 9-year period, a retrospective case comparison study of the pathology database was conducted at the University of Tokyo to identify tumor samples of oropharyngeal carcinoma. We performed immunohistochemistry for the p16 protein, in situ hybridization for human papillomavirus-deoxyribonucleic acid and polymerase chain reaction for the human papillomavirus-deoxyribonucleic acid oncogene E6 in oropharyngeal carcinoma in Japanese patients. We evaluated the human papillomavirus status in patients with oropharyngeal carcinoma to determine its prevalence and association with prognosis. We defined human papillomavirus(+) and human papillomavirus(-) oropharyngeal carcinoma cohorts as those with and without polymerase chain reaction for the human papillomavirus-deoxyribonucleic acid oncogene E6 or in situ hybridization-human papillomavirus. RESULTS In oropharyngeal carcinoma, the prevalences of p16(+)human papillomavirus(+), p16(+)human papillomavirus(-), p16(-)human papillomavirus(+) and p16(-)human papillomavirus(-) were 32% (48/150), 7% (10/150), 2% (3/150) and 59% (89/150), respectively. Low tobacco and alcohol consumption, tonsil or base of tongue localization, but not age, were associated with p16(+)human papillomavirus(+). Low alcohol consumption was associated with p16(+)human papillomavirus(-). There was a significant difference in overall survival between p16(+)human papillomavirus(-) and p16(-)human papillomavirus(-) (P = 0.03). In multivariate Cox regression models, p16 was the independent prognostic factor, regardless of human papillomavirus status. CONCLUSION p16 expression was a reliable prognostic biomarker regardless of human papillomavirus status.


Operations Research Letters | 2014

Clinical Features of Human Papilloma Virus-Related Head and Neck Squamous Cell Carcinoma of an Unknown Primary Site

Kenya Kobayashi; Yuki Saito; Go Omura; Mizuo Ando; Takashi Sakamoto; Tatsuya Yamasoba; Takahiro Asakage

Purpose: Head and neck squamous cell carcinoma of an unknown primary site (HNSCCUP) is a heterogeneous group of tumors that includes the human papillomavirus (HPV)-associated oropharyngeal squamous cell carcinoma. To investigate the relationship between HNSCCUP and HPV, we reviewed p16 overexpression and HPV DNA in lymph node metastases and examined their correlation with the primary site and clinical features. Materials and Methods: Thirty-three patients with HNSCCUP were retrospectively studied. Dissected neck metastases were analyzed for p16 overexpression by immunohistochemistry, and the presence of HPV DNA was investigated by in situ hybridization. Results: Of the 33 patients, 8 (24%) exhibited p16 overexpression. p16-positive lymph node metastases contained significantly more HPV DNA and were most frequently associated with occult primary lesions in the oropharynx and a favorable prognosis. Patients with a lower alcohol consumption, only level II/III metastasis, and cystic lymph node metastasis tended to have p16 overexpression. Conclusions: This is the first report on the relationship of HNSCCUP with p16 and HPV DNA status in Asian patients. In total, 24% of the HNSCCUP patients were p16 positive. p16 overexpression in neck metastasis was predictive of both an occult primary lesion in the oropharynx and an association with HPV infection. Alcohol consumption, location, and features of neck metastasis were correlated with p16 expression.


Japanese Journal of Clinical Oncology | 2014

Negative Human Papillomavirus Status and Excessive Alcohol Consumption are Significant Risk Factors for Second Primary Malignancies in Japanese Patients with Oropharyngeal Carcinoma

Yuki Saito; Yasuhiro Ebihara; Tetsuo Ushiku; Go Omura; Kenya Kobayashi; Mizuo Ando; Takashi Sakamoto; Masashi Fukayama; Tatsuya Yamasoba; Takahiro Asakage

OBJECTIVE To determine the clinical significance of human papillomavirus subclinical infection in patients with oropharyngeal squamous cell carcinoma in Japan. METHODS Over a 9-year period, a retrospective case comparison study of the pathology database was conducted at the University of Tokyo to identify samples of oropharyngeal squamous cell carcinoma. We performed in situ hybridization for human papillomavirus-DNA to identify subclinical human papillomavirus infections among patients with oropharyngeal squamous cell carcinoma. Second primary malignancies were classified as synchronous, if identified within 6 months of the diagnosis of the first tumor, or metachronous, if identified after this 6-month period. Univariate and multivariate analyses using logistic stepwise regression models were performed to identify factors associated with synchronous and metachronous second primary malignancy. RESULTS Of the 150 patients with oropharyngeal squamous cell carcinoma, 14% (21/150) and 20.7% (31/150) developed synchronous and metachronous second primary malignancies, respectively. Esophageal carcinoma was the most frequent second primary malignancy (10/21 for synchronous and 10/31 for metachronous second primary malignancies). The prevalence of oropharyngeal squamous cell carcinoma positive for human papillomavirus was 31% (47/150). Multivariate analysis identified alcohol consumption as a significant unfavorable risk factor for the occurrence of synchronous second primary malignancy, and either a human papillomavirus-negative status or N0 classification was a significant unfavorable risk factor for the occurrence of metachronous second primary malignancy. CONCLUSIONS Evaluation of the human papillomavirus status may help identify patients at risk for metachronous second primary malignancy. Upper gastrointestinal endoscopy is very important in the diagnosis of oropharyngeal squamous cell carcinoma among heavy drinkers in Japan.


Head and Neck-journal for The Sciences and Specialties of The Head and Neck | 2016

Comorbidity as predictor poor prognosis for patients with advanced head and neck cancer treated with major surgery

Go Omura; Mizuo Ando; Yuki Saito; Kenya Kobayashi; Tatsuya Yamasoba; Takahiro Asakage

The impact of comorbidities on patients with advanced head and neck cancer treated with major surgery has not been reported before.


Otolaryngology-Head and Neck Surgery | 2015

Nerve Growth Factor Signals as Possible Pathogenic Biomarkers for Perineural Invasion in Adenoid Cystic Carcinoma

Kenya Kobayashi; Mizuo Ando; Yuki Saito; Kenji Kondo; Go Omura; Aya Shinozaki-Ushiku; Masashi Fukayama; Takahiro Asakage; Tatsuya Yamasoba

Objective The molecular mechanisms underlying perineural invasion (PNI)—a characteristic pathological feature of adenoid cystic carcinoma (ACC)—remain largely unclear. Recently, nerve growth factor (NGF) has been implicated in perineural invasion in certain malignancies. Overexpression of Myb related to the MYB-NFIB fusion gene in ACC has also been correlated with perineural invasion and survival. However, this concept is controversial. The aim of this study was to examine the expression of NGF together with its receptors, tropomyosin receptor kinase A (TrkA) and p75NRT, and Myb in ACC and assess their relationship with perineural invasion and survival. Study Design Case series with chart review. Setting The University of Tokyo Hospital. Subjects and Methods We retrospectively analyzed 37 patients with ACC surgically treated from 1991 to 2011. We examined expression levels of NGF, TrkA, p75NRT, and Myb in the ACC specimens and their correlations with PNI and prognosis. Results NGF, TrkA, p75NRT, and Myb overexpression rates were 65%, 65%, 30%, and 62%, respectively. Pearson product-moment correlation coefficient revealed a strong correlation between NGF/TrkA immunostaining and PNI (NGF: r = 0.68, P < .0001; TrkA: r = 0.53, P = .0007). Moreover, NGF overexpression was significantly associated with worse 8-year local control rate (27% vs 80%, P = .005). However, p75NRT and Myb expression was related to neither perineural invasion nor survival. Conclusion Our findings demonstrated that NGF and TrkA overexpression, but not Myb and p75NRT overexpression, may contribute to PNI and thus cause local recurrence in patients with ACC.


Head and Neck-journal for The Sciences and Specialties of The Head and Neck | 2015

Maxillary carcinosarcoma: Identification of a novel MET mutation in both carcinomatous and sarcomatous components through next generation sequencing.

Mizuo Ando; Yuki Saito; Teppei Morikawa; Go Omura; Kenya Kobayashi; Ken Akashi; Masafumi Yoshida; Yasuhiro Ebihara; Chisato Fujimoto; Masashi Fukayama; Tatsuya Yamasoba; Takahiro Asakage

Carcinosarcoma is a rare tumor with biphasic growth of the carcinomatous and sarcomatous components. Prognosis is generally poor and characterization of the molecular mechanisms may provide information for the development of novel antitumor agents and biomarkers.


ORL | 2016

Clinical Value of the Epstein-Barr Virus and p16 Status in Patients with Nasopharyngeal Carcinoma: A Single-Centre Study in Japan

Yuki Saito; Tetsuo Ushiku; Go Omura; Kazuo Yasuhara; Masafumi Yoshida; Wataru Takahashi; Mizuo Ando; Masashi Fukayama; Tatsuya Yamasoba

Background: The clinical significance of the Epstein-Barr virus (EBV) status and p16 expression was unknown in nasopharyngeal carcinoma (NPC). Methods: We retrospectively studied our pathology database for 13 years to determine the prevalence of EBV and p16 expression and their association with prognosis in cases of NPC. We performed immunohistochemistry for the p16 protein and in situ hybridization (ISH) for EBV-encoded small RNAs and human papillomavirus (HPV) DNA. Results: Of the 43 patients with NPC, 27 (63%), 6 (14%), and 10 (23%) cases were EBV positive, EBV negative with keratinization, and EBV negative without keratinization, respectively. No cases were HPV positive by ISH. Among the 21 EBV-positive tumours that were tested for p16, only 2 tumours were p16 positive. The keratinization-positive group included only males, typically >60 years of age (5 of 6) and with T4 tumours (3 of 6). In contrast, the EBV-positive cohort tended to be younger (<60 years, 13 of 27) and have progressive N-stage tumours (N2-3, 14 of 27). The keratinization and EBV-negative cohort included predominantly males (9 of 10) who were likely p16 negative (4 of 10) and smokers (7 of 10). Multivariate analysis confirmed that keratinization was an independent prognostic factor for progression-free survival. Conclusion: In areas, such as Japan, that are nonendemic for both EBV and HPV, the causality of NPC appears to be more heterogeneous.


Head and Neck-journal for The Sciences and Specialties of The Head and Neck | 2016

Association of the upregulated expression of focal adhesion kinase with poor prognosis and tumor dissemination in hypopharyngeal cancer

Go Omura; Mizuo Ando; Yuki Saito; Kenya Kobayashi; Masafumi Yoshida; Yasuhiro Ebihara; Kaori Kanaya; Chisato Fujimoto; Takashi Sakamoto; Kenji Kondo; Takahiro Asakage; Tatsuya Yamasoba

Focal adhesion kinase (FAK) plays an important role in tumor metastasis. The purpose of this study was to evaluate the significance of FAK expression in surgically treated patients with hypopharyngeal cancer.

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