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Dive into the research topics where Yasuo Toyozumi is active.

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Featured researches published by Yasuo Toyozumi.


World Journal of Surgical Oncology | 2011

Changes in the ER, PgR, HER2, p53 and Ki-67 biological markers between primary and recurrent breast cancer: discordance rates and prognosis

Reiki Nishimura; Tomofumi Osako; Yasuhiro Okumura; Rumiko Tashima; Yasuo Toyozumi; Nobuyuki Arima

BackgroundIn breast cancer, ER/PgR, HER2, and Ki-67 are important biological markers for predicting prognosis and making effective treatment decisions. In addition, changes in markers due to relapse are also clinically experienced; however, the frequency and clinical significance are still not fully understood. Thus, changes in markers and their correlations with prognosis were investigated.Patients and MethodsOut of the patients with relapse from 1997 to March 2011, there were 97 consecutive patients from whom the lesion was resected and evaluated by immunostaining. The biopsy sites were chest wall, lymph node, ipsilateral breast tumor recurrence, lungs, bones, ovaries and brain. The markers sought were ER, PgR, HER2, p53 and Ki-67.ResultsThe hormone receptor positive rate from the primary tumor to recurrence decreased from 63.9% to 57.7% and from 56.7% to 43.3% for ER and PgR, respectively. Changes in the positive/negative evaluation were seen at the rate of 10.3% and 25.8% for ER and PgR, respectively. The Ki-67 index increased significantly from a mean of 29.1% at primary tumor to 36.3% at relapse. When divided into 2 groups (< 50% and ≥50%), changes were seen in 24.7%. On the other hand, the rates of changes in HER2 and p53 positivity were 14.4% and 12.4%. The changes in subtypes were seen in 25%, however, the lowest rate of change was seen in the triple negative cases. Although there was no notable difference in the rate of change between disease-free interval (DFI) and PgR, Ki-67, p53 and HER2, there was a significant difference in the change rates in the ER. A multivariate analysis revealed that the status of distant metastasis and PgR level at relapse, and Ki-67 levels at primary tumor were all significant factors.ConclusionEstrogen receptor and PgR decreased while Ki-67 increased due to relapse; however, the rate of change was high for PgR and Ki-67. Change in the subtypes was seen in 25%. In addition, PgR at relapse and Ki-67 at primary tumor were significant factors for post-relapse prognosis while PgR becoming negative was a poor prognostic factor. These findings are important for making effective treatment decisions.


Human Pathology | 2009

Hyperactivated STAT3 in ALK-positive diffuse large B-cell lymphoma with clathrin-ALK fusion.

Shuji Momose; Jun-ichi Tamaru; Hirohisa Kishi; Ittaku Mikata; Masaya Mori; Yasuo Toyozumi; Shinji Itoyama

Anaplastic lymphoma kinase (ALK)-positive large B-cell lymphoma is a rare subtype of diffuse large B-cell lymphoma (DLBCL). Although a few cases of ALK-positive large B-cell lymphoma harbor nucleophosmin-ALK chromosomal translocation similar to ALK-positive anaplastic large cell lymphoma, most reported cases are characterized by t(2;17)(p23;q23) involving the clathrin gene. Here, we report 2 cases of ALK-positive DLBCL. The 2 cases presented similar morphologic features and immunohistochemical characteristics, that is, positivity for ALK, IgA, CD138, and MUM1; weak positivity for CD30 and CD79a; and negativity for CD20. The clathrin-ALK transcript was identified by reverse transcription-polymerase chain reaction, and the sequence was determined by direct sequencing. Recently, the essential role of STAT3 activation as well as STAT 5 activation in nucleophosmin-ALK fusion protein-mediated lymphomagenesis was reported. However, differential effects of ALK-fusion variant proteins on proliferation, transformation, and invasion properties were reported. Thus, we evaluated the phosphorylation status of STAT 3 and STAT 5, and found highly hyperphosphorylated STAT 3 on tyrosine 705 but not STAT 5 in our 2 cases of ALK-positive DLBCL with clathrin-ALK fusion. Furthermore, STAT 5A expression was not detected in either of the ALK-positive DLBCL cases, although 11 of the 36 ALK-negative DLBCL cases revealed STAT 5A expression. Expression of the antiapoptotic proteins survivin and BCL-X(L), which were believed to be the targets of STAT 3, was investigated. However, there were no significant associations between expression of survivin or BCL-X(L) and ALK positivity among the diffuse large B-cell lymphomas. In summary, similar signaling transduction mechanism involving STAT proteins seems to underlie DLBCL harboring the clathrin-ALK or nucleophosmin-ALK fusion gene.


Oncology | 2013

Evaluation of Factors Related to Late Recurrence - Later than 10 Years after the Initial Treatment - in Primary Breast Cancer

Reiki Nishimura; Tomofumi Osako; Yasuyuki Nishiyama; Rumiko Tashima; Masahiro Nakano; Mamiko Fujisue; Yasuo Toyozumi; Nobuyuki Arima

Background: Breast cancer is associated with a relatively good prognosis. Prognostic factors examined to date are related to early recurrence while those related to late recurrence and their countermeasures remain unclear. Therefore, we examined the factors related to late recurrence. Patients and Methods: From January 1980 to August 2012, 4,774 patients who underwent primary treatment and estrogen (ER) and progesterone receptor (PgR) assessment were enrolled in this study. The patients were divided into two groups, those with a follow-up period <10 years and those without any recurrence at 10 years but who continued follow-up examinations. Recurrence occurred in 711 patients followed up for <10 years and in 51 patients for ≥10 years. Results: The overall 10-year cumulative disease-free survival rate was 79.5%, and the recurrence rate at ≥10 years was 5.8%. A multivariate analysis revealed that the factors related to late recurrence were PgR positivity and positive nodes. This result differed from that for early recurrence in terms of ER/PgR, Ki-67 index and p53 overexpression. Conclusion: PgR positivity and lymph node metastases significantly correlated with late recurrence. Therefore, it is important to evaluate appropriate measures such as treatment period and treatment regimen for hormone-sensitive patients.


PLOS ONE | 2015

Evaluation of an Optimal Cut-Off Point for the Ki-67 Index as a Prognostic Factor in Primary Breast Cancer: A Retrospective Study

Rumiko Tashima; Reiki Nishimura; Tomofumi Osako; Yasuyuki Nishiyama; Yasuhiro Okumura; Masahiro Nakano; Mamiko Fujisue; Yasuo Toyozumi; Nobuyuki Arima

The Ki-67 index is an important biomarker for indicating the proliferation of cancer cells and is considered to be an effective prognostic factor for breast cancer. However, a standard cut-off point for the Ki-67 index has not yet been established. Therefore, the aim of this retrospective study was to determine an optimal cut-off point in order to establish it as a more accurate prognostic factor. Immunohistochemical analysis of the Ki-67 index was performed on 4329 patients with primary breast cancer from August 1987 to March 2012. Out of this sample, there were 3186 consecutive cases from September 1997 with simultaneous evaluations of ER, PgR and HER2 status. Coxs proportional hazard model was used to perform univariate and multivariate analyses of the factors related to OS. The hazard ratios (HR) and the p values were then compared to determine the optimal cut-off point for the Ki-67 index. The median Ki-67 index value was 20.5% (mean value 26.2%). The univariate analysis revealed that there was a statistically significant negative correlation with DFS and OS and the multivariate analysis revealed that the Ki-67 index value was a significant factor for DFS and OS. The top seven cut-off points were then carefully chosen based on the results of the univariate analysis using the lowest p-values and the highest HR as the main selection criteria. The multivariate analysis of the factors for OS showed that the cut-off point of 20% had the highest HR in all of the cases. However, the cutoff point of 20% was only a significant factor for OS in the Luminal/HER2- subtype. There was no correlation between the Ki-67 index value and OS in any of the other subtypes. These data indicate that the optimal cut-off point of 20% is the most effective prognostic factor for Luminal/HER2- breast cancer.


Cancers | 2012

Clinical Significance of CK19 Negative Breast Cancer

Mamiko Fujisue; Reiki Nishimura; Yasuhiro Okumura; Rumiko Tashima; Yasuyuki Nishiyama; Tomofumi Osako; Yasuo Toyozumi; Nobuyuki Arima

Analysis of sentinel lymph nodes (SLNs) by means of One-Step Nucleic Acid Amplification (OSNA) is gaining widespread use as a quick and accurate method. This assay detects the expression level of cytokeratin 19 (CK19) which is present in some but not all breast tumors. In this study, the clinical significance of negative CK19 was investigated in 219 cases of primary breast cancer. In 179 patients with clinically negative nodes, OSNA and imprint smear cytology of SLN were performed simultaneously. The OSNA revealed a node-positive rate of 24.6%. Negative CK19 correlated significantly with negative ER/PgR and higher Ki-67 values, and marginally with higher nuclear grade and p53 overexpression. The triple negative subtype showed lower CK19 expression. OSNA revealed that one of the negative CK19 cases was actually a false negative but this was corrected with the use of the imprint smear cytology. In conclusion, CK19 negativity reflected the aggressiveness of primary breast cancer. OSNA assay used to analyze SLN was useful, but there is a possibility that it will mistakenly detect false negatives in CK19 negative tumors. Therefore, in tumors with negative CK19, the imprint smear cytology may be more useful in cases with macrometastasis.


Acta Cytologica | 2006

Glassy cell carcinoma of the cervix: cytologic features and expression of estrogen receptor, progesterone receptor and Her2/neu protein.

Hajime Kuroda; Yasuo Toyozumi; Tomoko Masuda; Tomohiko Ougida; Kyota Hanami; Kiuchi Kyoko; Jun-ichi Tamaru; Shinji Itoyama

OBJECTIVE To analyze the cytologic features, estrogen and progesterone receptors, and Her2/neu protein in glassy cell carcinoma (GCC) of the cervix. STUDY DESIGN Cases were analyzed using various parameters, including age at presentation, stage, treatment and clinical course. Between 1990 and 2003, patients with primary cervical carcinomas were treated and cytopathologic analyses performed. Tests for estrogen receptor (ER), progesterone receptor (PR) and Her2/neu protein were performed on paraffin sections. RESULTS GCC of the cervix is composed of large cells with abundant chromatin, which gives them their characteristic glassy appearance. Eleven cases were identified as GCC. One case (9.1%) was correctly diagnosed from the cervicovaginal smear. Among the GCC cases, ER, PR and Her2/neu were positive in 2 (18.1%), 1 (9.1%) and 5 (45.4%) cases, respectively. CONCLUSION Cytology of GCC reveals characteristic features that differ from those of other carcinomas of the cervix. GCC has unique cytologic characteristics and causes diagnostic confusion, possibly leading to incorrect diagnoses. The reason for such low diagnostic precision in cytology might be due to the lack of differentiation and low frequency of this tumor. Our results, demonstrating Her2/ neu overexpression, may correlate with more aggressive behavior and a worse clinical outcome.


Journal of Clinical Pathology | 2016

The importance of tissue handling of surgically removed breast cancer for an accurate assessment of the Ki-67 index.

Nobuyuki Arima; Reiki Nishimura; Tomofumi Osako; Yasuyuki Nishiyama; Mamiko Fujisue; Yasuhiro Okumura; Masahiro Nakano; Rumiko Tashima; Yasuo Toyozumi

Aim Insufficient attention for the Ki-67 immunohistochemistry has been given to the importance of tissue handling for surgical breast cancer specimens. We sought to investigate the effect of fixation status on the Ki-67. Methods We examined the effect of fixative, time to and duration of fixation using surgical specimens, and finally, compared the paired Ki-67 index in the tumour between core needle and surgical specimen. Results The Ki-67 was significantly higher when 10% neutral buffered formalin was used (p=0.0276). Insufficient fixation caused a drastic reduction in the Ki-67 index (p=0.0177), but not significant in oestrogen receptor (ER) and human epidermal growth factor receptor 2 (HER2). Sixteen hours delayed time to fixation also caused a reduction of the Ki-67 (p=0.0284), but not significant in ER. Prolonged fixation significantly led to a gradual reduction in the Ki-67 in a time-dependent manner, but not in both ER and HER2. Finally, cutting the tumour before fixation improved fixation status and consequently caused an increased level of the Ki-67 index (p=0.0181), which resulted in a strong correlation of the Ki-67 between core needle and surgical specimen (r=0.8595). Conclusions Tissue handling of surgical specimen is critical for assessing the Ki-67 compared with ER and HER2. We should pay more attention to tissue fixation status for the standard assessment of the Ki-67 index.


Surgery Today | 2006

Clinical and Pathologic Features of Fibroadenoma of the Mastopathic Type

Hajime Kuroda; Ikuya Takeuchi; Kiyoshi Ohnishi; Goi Sakamoto; Futoshi Akiyama; Yasuo Toyozumi; Shuji Momose; Jun-ichi Tamaru; Shinji Itoyama

PurposeFibroadenoma with mastopathic change (FAM) is a relatively uncommon subtype of fibroadenoma of the breast, with a high incidence of pathological misdiagnosis. This histological subtype remains poorly understood because of its rarity. Many questions remain unanswered about its clinicopathological importance, especially in the differential diagnosis of breast cancers.MethodsAmong 218 breast fibroadenomas surgically resected as excisional biopsies at our institute between 1990 and 2004, 19 were pathologically diagnosed as FAM. We reviewed these 19 patients.ResultsThe ages of the patients ranged from 20 to 51 years (mean 36.8 years). The tumor sizes ranged from 0.8 to 7 cm (mean 2.1 cm). Six of the 19 patients underwent core needle biopsy, resulting in a diagnosis of fibroadenoma in four patients and atypical ductal hyperplasia in two patients. Ultrasonography showed findings suggestive of solid tubular carcinoma in seven patients, fibroadenoma in ten patients, and unspecific malignant tumors in two. They were not specified clinically.ConclusionRecognition of this distinctive variant of fibroadenoma is important because it resembles intraductal carcinoma and is increasing in incidence. It is crucial to distinguish FAM from intraductal carcinoma in biopsy specimens. Thus, not only pathologists but also clinicians must be able to recognize this type of fibroadenoma, and cooperate closely to establish an accurate diagnosis.


The Breast | 2015

Survival time according to the year of recurrence and subtype in recurrent breast cancer.

Masahiro Nakano; Mamiko Fujisue; Rumiko Tashima; Yasuhiro Okumura; Yasuyuki Nishiyama; Tomofumi Ohsako; Yasuo Toyozumi; Nobuyuki Arima; Reiki Nishimura

BACKGROUND Survival for patients with recurrent breast cancer has improved over time due to the introduction of modern systemic therapy. The aim of this study was to determine the impact of subtype and the year of recurrence on the survival times of recurrent breast cancer. METHODS Between 1979 and 2013, 813 patients who underwent initial treatment for primary breast cancer experienced recurrence. They were divided into two groups based on the year of recurrence; before 2000 and after 2001. Survival after recurrence was compared between these groups based on following criteria; subtypes, disease free interval (DFI), and dominant recurrent site. The median follow-up period after recurrence was 4.3 years. RESULTS Survival improved significantly in the after 2001 group, and a significant improvement in survival was only seen in the HER2-enriched subtype. Multivariate analysis revealed that DFI, ER, HER2 status, dominant recurrent site and the Ki-67 index value were significant prognostic factors. In the HER2-enriched subtype, the year of recurrence, DFI and dominant recurrent site were significant independent factors. In the other subtypes, these factors were not correlated with survival. CONCLUSION Our study revealed that the survival rate of patients with only the HER2-enriched subtype significantly improved after recurrence. To prolong the survival time after recurrence of both luminal and triple negative subtypes, the development of novel targeting therapies to overcome refractory recurrent breast cancer is extremely important.


Oncology | 2015

A Comparison of the Hot Spot and the Average Cancer Cell Counting Methods and the Optimal Cutoff Point of the Ki-67 Index for Luminal Type Breast Cancer

Nobuyuki Arima; Reiki Nishimura; Tomofumi Osako; Yasuyuki Nishiyama; Mamiko Fujisue; Yasuhiro Okumura; Masahiro Nakano; Rumiko Tashima; Yasuo Toyozumi

Objective: In this case-control study, we investigated the most suitable cell counting area and the optimal cutoff point of the Ki-67 index. Methods: Thirty recurrent cases were selected among hormone receptor (HR)-positive/HER2-negative breast cancer patients. As controls, 90 nonrecurrent cases were randomly selected by allotting 3 controls to each recurrent case based on the following criteria: age, nodal status, tumor size, and adjuvant endocrine therapy alone. Both the hot spot and the average area of the tumor were evaluated on a Ki-67 immunostaining slide. Results: The median Ki-67 index value at the hot spot and average area were 25.0 and 14.5%, respectively. Irrespective of the area counted, the Ki-67 index value was significantly higher in all of the recurrent cases (p < 0.0001). The multivariate analysis revealed that the Ki-67 index value of 20% at the hot spot was the most suitable cutoff point for predicting recurrence. Moreover, higher ΔKi-67 index value (the difference between the hot spot and the average area, ≥10%) and lower progesterone receptor expression (<20%) were significantly correlated with recurrence. Conclusion: A higher Ki-67 index value at the hot spot strongly correlated with recurrence, and the optimal cutoff point was found to be 20%.

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Seiya Kato

University of the Ryukyus

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Shinji Itoyama

Saitama Medical University

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Jun-ichi Tamaru

Saitama Medical University

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