Yoshihiro Ohishi

Histological classification of ovarian cancer.

 The histology of ovarian tumors exhibits a wide variety of histological features. The histological classification of ovarian tumors by the World Health Organization (WHO) is based on histogenetic principles, and this classification categorizes ovarian tumors with regard to their derivation from coelomic surface epithelial cells, germ cells, and mesenchyme (the stroma and the sex cord). Epithelial ovarian tumors, which are the majority of malignant ovarian tumors, are further grouped into histological types as follows: serous, mucinous, endometrioid, clear cell, transitional cell tumors (Brenner tumors), carcinosarcoma, mixed epithelial tumor, undifferentiated carcinoma, and others. Clear cell and endometrioid carcinomas are highly associated with endometriosis. In stage distribution, serous carcinoma is found predominantly is stage III or IV. In contrast, clear cell and endometrioid carcinomas tend to remain confined to the ovary. Clear cell and endometrioid carcinomas may be unique histological types compared with serous carcinomas with respect to stage distribution and association with endometriosis.

Endometrial stromal sarcomas and related high-grade sarcomas : immunohistochemical and molecular genetic study of 31 cases

Classification and terminology of non–low-grade endometrial sarcomas, which show significant nuclear atypia, have been controversial. Currently, these tumors seem to be classified all together into “undifferentiated endometrial sarcoma (UES).” However, it remains unclear whether these non–low-grade sarcomas are universally “undifferentiated.” We divided these sarcomas morphologically into undifferentiated endometrial sarcoma with nuclear uniformity (UES-U) and undifferentiated endometrial sarcoma with nuclear pleomorphism (UES-P), and compared their molecular genetic and immunohistochemical profiles. Eighteen low-grade endometrial stromal sarcomas (ESS-LG), 7 UES-U, and 6 UES-P were examined. All the patients with ESS-LG were still alive, either with or without disease, whereas 4 of the 5 patients with advanced stage UES-U and all 3 of the patients with advanced stage UES-P had died of the disease. JAZF1-JJAZ1 fusion transcript was detected in 6 (50%) out of 12 ESS-LG and in 1 (33%) of 3 UES-U, whereas it was not detected in any of the cases of UES-P. ESS-LG and UES-U frequently showed positive immunoreaction for estrogen receptor (ESS-LG: 94%, UES-U: 57%) and progesterone receptor (ESS-LG: 94%, UES-U: 57%), whereas all the UES-P were negative for these receptors. Nuclear β-catenin expression was more frequently recognized in ESS-LG (47%) and UES-U (85%), compared with UES-P (33%). Moreover, nuclear accumulation of p53 and TP53 gene missense mutations were limited to 3 UES-P cases. Our data suggest that UES-U shares some molecular genetic and immunohistochemical characteristics with ESS-LG, but UES-P considerably differs from ESS-LG.

Clinicopathological characteristics of mucinous adenocarcinoma of the ovary

OBJECTIVE We conducted the present study to clarify the clinicopathological characteristics of mucinous adenocarcinoma. METHODS Two hundred twenty-five patients were diagnosed with mucinous adenocarcinoma at individual institutes and underwent primary treatment between 1998 and 2003. Of these patients, 189 patients who could undergo central pathological review were enrolled in this study. Of 189 patients undergoing central pathological review, 64 patients (33.9%) were diagnosed with mucinous invasive adenocarcinoma, 45 mucinous intraepithelial carcinoma, and 42 mucinous tumor of borderline malignancy. Twenty-five patients were diagnosed with other histological subtypes, including 8 endometrioid adenocarcinoma, 5 clear cell carcinoma, 3 serous adenocarcinoma, and 4 mixed type. There were 13 cases of metastatic mucinous adenocarcinoma, including 7 pseudomyxoma peritonei. Four hundred thirty-three patients with serous adenocarcinoma were used as controls. RESULTS Forty-five patients with mucinous invasive carcinoma were in FIGO I-II stages and 19 in III-IV stages. There was no difference in the outcome between mucinous invasive adenocarcinoma and serous adenocarcinoma in I-II stage patients and III-IV stage patients with optimal operation. In contrast, patients with mucinous invasive adenocarcinoma receiving suboptimal operation showed a significantly worse prognosis (survival rate: 27.8% vs. 61.5%). The response rate to chemotherapy for mucinous invasive adenocarcinoma was significantly lower than for serous adenocarcinoma (12.5% vs. 67.7%). CONCLUSIONS The diagnosis of mucinous invasive adenocarcinoma was difficult. Since patients with mucinous invasive adenocarcinoma had a lower response to chemotherapy, aggressive cytoreductive surgery was an effective treatment to improve the prognosis for advanced stage patients. A new chemotherapeutic regimen should be established for mucinous adenocarcinoma of the ovary.

Prognostic implications of the nuclear localization of Y-box-binding protein-1 and CXCR4 expression in ovarian cancer: Their correlation with activated Akt, LRP/MVP and P-glycoprotein expression

The nuclear localization of Y‐box‐binding protein‐1 (YB‐1) is known to be a poor prognostic factor in several human malignancies, including ovarian carcinoma. Following on from our basic study dealing with microarray analyses of YB‐1‐associated gene expression in ovarian cancer cells, we examined whether nuclear localization of YB‐1 is associated with the expression of CXCR4, a vault protein named lung resistance‐related vault protein (LRP/MVP), phosphorylated Akt (p‐Akt) or P‐glycoprotein (P‐gp) in human ovarian carcinoma. Fifty‐three surgically resected ovarian carcinomas treated with paclitaxel and carboplatin were examined immunohistochemically for nuclear YB‐1 expression and intrinsic expression of p‐Akt, P‐gp, LRP/MVP and CXCR4. Nuclear expression of YB‐1 demonstrated significant correlation with p‐Akt, P‐gp and LRP expression, but no relationship with CXCR4 expression. By multivariate analysis, only YB‐1 nuclear expression and CXCR4 expression were independent prognostic factors with regard to overall survival. These results indicate that YB‐1 nuclear expression and CXCR4 expression are important prognostic factors in ovarian carcinoma. (Cancer Sci 2007; 98: 1020–1026)

Prognostic significance of microvessel density, vascular cuffing and vascular endothelial growth factor expression in ovarian carcinoma: a special review for clear cell adenocarcinoma.

Our purpose is to demonstrate the relationship between microvessel density (MVD), vascular cuffing (VC), vascular endothelial growth factor (VEGF) expression and clinicopathological parameters in ovarian cancer. Surgical specimens from 105 primary ovarian cancers were examined for vascularization and VEGF expression by immunohistochemical staining. The higher MVD group (MVD> or =70) and the positive VEGF group were associated with better progression-free survival only in early stages. The significant association of the MVD with better progression-free survival was recognized only in the patients with clear cell adenocarcinomas. The complete VC group showed a similar trend as MVD though there was no statistical difference. A multivariate analysis revealed MVD to correlate independently with progression-free survival. In ovarian carcinoma, MVD was found to be an independent prognostic factor. In addition, the higher MVD with clear cell adenocarcinoma had the better prognosis. The clinicopathological role of angiogenesis should be analyzed taking account of histologic type.

Coincident expression of β -catenin and cyclin D1 in endometrial stromal tumors and related high-grade sarcomas

Aberrant activation of the Wnt signaling pathway has been implicated in tumorigenesis of a wide range of tumors, including colorectal cancer. Regarding endometrial stromal tumors and related high-grade sarcomas, there have been some reports regarding nuclear accumulation of β-catenin. To clarify the function of the aberrant Wnt signaling pathway in these tumors, we searched for mutations of the CTNNB1 (β-catenin) gene and APC gene by PCR direct sequencing and analyzed the methylation status of SFRP genes. We also examined overexpression of cyclin D1 and MMP-7, which are direct target genes of β-catenin. Eight endometrial stromal nodules, 16 low-grade endometrial stromal sarcomas, and 13 undifferentiated endometrial sarcomas were examined. PCR and direct sequencing revealed no mutation of the β-catenin gene or the APC gene. Concerning the promoter methylation status of SFRP genes, methylation-specific PCR revealed no significant difference between the group with nuclear β-catenin expression and that without nuclear β-catenin expression. Immunohistochemistry revealed overexpression of cyclin D1 in 2 out of 8 endometrial stromal nodules, 1 out of 17 low-grade endometrial stromal sarcomas, and 6 out of 13 undifferentiated endometrial sarcomas, and these 6 undifferentiated endometrial sarcomas simultaneously expressed nuclear β-catenin. Interestingly, all six undifferentiated endometrial sarcoma cases with cyclin D1 overexpression histologically featured rather uniform nuclei. In contrast, the six cases of undifferentiated endometrial sarcoma with highly pleomorphic nuclei were all negative for cyclin D1. In conclusion, among endometrial stromal tumors and related sarcomas, undifferentiated endometrial sarcomas featuring uniform nuclei were characterized by frequent coincident expression of β-catenin and cyclin D1. This finding raises the possibility that cyclin D1 is upregulated by β-catenin in these high-grade sarcomas previously called high-grade endometrial stromal sarcoma.

Overexpression of Class III β-Tubulin Predicts Good Response to Taxane-Based Chemotherapy in Ovarian Clear Cell Adenocarcinoma

Purpose: Of the various microtubule-associated molecules, β-tubulin III has been reported to be closely associated with the therapeutic efficacy of taxane-based chemotherapy against ovarian cancer. Stathmin and microtubule-associated protein 4 (MAP4) have been reported to play an important role in microtubule stabilization. In this study, we investigated whether expression of these microtubule-associated factors affects the therapeutic efficacy of taxane-based chemotherapy in ovarian clear cell adenocarcinoma. Experimental Design: Drug sensitivity of paclitaxel or cisplatin was assessed in ovarian cancer cell lines treated with small interfering RNA of tubulin isoforms, MAP4, and stathmin. We examined 94 surgically resected ovarian clear cell adenocarcinoma specimens from patients treated with taxane-containing regimens (n = 44) and with taxane-free regimens (n = 50), using immunohistochemistry to detect expression of β-tubulin III, stathmin, and MAP4. Results: Knockdown of β-tubulin III and IV specifically conferred drug resistance to paclitaxel in one ovarian cancer cell line, but not to other molecules. Estimated overall survival revealed a significant synergistic effect between taxane and β-tubulin III in patients with ovarian clear cell adenocarcinoma. Of three microtubule-related molecules, among the taxane-based chemotherapy group, cases with higher β-tubulin III expression were associated with a significantly more favorable prognosis compared with those having lower β-tubulin III expression. By contrast, there was no statistical significance in the synergistic relationships between stathmin and taxane or between MAP4 and taxane. Conclusions: Taxane-based chemotherapy was effective for patients with ovarian clear cell adenocarcinomas who were positive for β-tubulin III but not for those who were negative for these proteins.

Immunohistochemical characterization of mullerian mucinous borderline tumors: possible histogenetic link with serous borderline tumors and low-grade endometrioid tumors

Mullerian mucinous borderline tumor and gastrointestinal mucinous borderline tumor are considered mucinous tumor subtypes. However, it has been reported that mullerian mucinous borderline tumor shares many clinicopathologic features with serous borderline tumor. Furthermore, some investigators have explained the histogenesis of mullerian mucinous borderline tumor by metaplastic and hyperplastic transformation of endometriosis (Fukunaga M, Ushigome S. Epithelial metaplastic changes in ovarian endometriosis. Mod Pathol. 1998;11:784-788). The purpose of this study is to substantiate the concept that mullerian mucinous borderline tumor is histogenetically closer to serous borderline tumor or low-grade endometrioid tumor than to gastrointestinal mucinous borderline tumor by directly comparing their immunophenotype. A total of 80 cases of low-grade ovarian tumors composed of 20 mullerian mucinous borderline tumors, 20 gastrointestinal mucinous borderline tumors, 20 serous borderline tumors, and 20 low-grade endometrioid tumors were immunohistochemically evaluated for the expression of estrogen receptor, progesterone receptor, vimentin, WT-1, beta-catenin, and PTEN. Almost all cases of mullerian mucinous borderline tumor, serous borderline tumor, and low-grade endometrioid tumor showed diffuse and strong nuclear expression of estrogen receptor and progesterone receptor. In addition, about half of the mullerian mucinous borderline tumor, serous borderline tumor, and low-grade endometrioid tumor cases showed focal but strong vimentin cytoplasmic expression. In contrast, gastrointestinal mucinous borderline tumor showed no expression of estrogen receptor, progesterone receptor, or vimentin, except for 1 case in which estrogen receptor expression was very focally and weakly observed. WT-1 nuclear expression was observed in most serous borderline tumors and only 15% of low-grade endometrioid tumor, but mullerian and gastrointestinal mucinous borderline tumor cases were completely negative. beta-Catenin nuclear expression was significantly more frequent in low-grade endometrioid tumor than in mullerian mucinous borderline tumor, gastrointestinal mucinous borderline tumor, or serous borderline tumor. PTEN expression was significantly lower in low-grade endometrioid tumor than in mullerian mucinous borderline tumor, gastrointestinal mucinous borderline tumor, and serous borderline tumor. Multiple comparisons of quantitative immunoreactivities of estrogen receptor, progesterone receptor, and vimentin revealed that the gastrointestinal mucinous borderline tumor expression profiles were significantly different from those of mullerian mucinous borderline tumors, serous borderline tumors, and low-grade endometrioid tumors. The immunohistochemical expression profiles of estrogen receptor, progesterone receptor, and vimentin substantiate the concept that the histogenesis of mullerian mucinous borderline tumor is closer to those of serous borderline tumor and low-grade endometrioid tumor than to that of gastrointestinal mucinous borderline tumor. However, aberrant beta-catenin and PTEN protein expression, both of which are known to contribute to the tumorigenesis of low-grade endometrioid tumor, appeared to be less important for the tumorigenesis of mullerian mucinous borderline tumor.

Squamous cell carcinoma arising in mature cystic teratoma of the ovary: an immunohistochemical analysis of its tumorigenesis.

Aims:  Squamous cell carcinoma (SCC) is the most common form of malignant transformation in mature cystic teratoma (MCT) of the ovary. Some investigators have suggested the possibility of origin from columnar epithelium. The aim of this study was to analyse such tumours immunohistochemically to elucidate their histogenesis.

ATP-binding cassette superfamily transporter gene expression in human soft tissue sarcomas.

The phenomenon of multidrug resistance (MDR) in various malignant neoplasms has been reported as being caused by one or multiple expressions of ATP‐binding cassette (ABC) superfamily protein, including P‐glycoprotein/multidrug resistance (MDR) 1 and the MDR protein (MRP) family. However, their expression levels and distribution within soft tissue sarcomas remain controversial. In 86 cases of surgically resected soft tissue sarcoma, intrinsic mRNA levels of MDR1, MRP1, MRP2 and MRP3 were assessed using a quantitative reverse transcriptase‐PCR (RT‐PCR) method. Moreover, immunohistochemical protein expressions of P‐glycoprotein (P‐gp), MRP1, MRP2, MRP3 and p53 protein were evaluated in concordant paraffin‐embedded material. The mRNA expression and immunohistochemical expression of ABC superfamily transporters were compared to clinicopathologic parameters and proliferative activities as evaluated by the MIB‐1‐labeling index (LI). Among the various histologic types, malignant peripheral nerve sheath tumor (MPNST) showed significantly high levels of MDR1 (p=0.017) and MRP3 (p=0.0384) mRNA expression, compared to the other tumor types. When the immunohistochemical method was compared to the RT‐PCR technique to assess ABC transported expression at the protein and mRNA levels, a significantly close relationship was found between the 2 methods (p<0.05). P‐gp expression was significantly correlated with large tumor size (≥5 cm, p=0.041) and high AJCC stage (stages III and IV) (p=0.0365). Furthermore, cases with nuclear expression of p53 revealed significantly higher levels of MDR1 mRNA expression, compared to those with negative immunoreaction for p53 (p=0.0328). Our results suggest that MDR1/P‐gp expression may have an important role to play in tumor progression in the cases of soft tissue sarcoma, and p53 may be one of the active regulators of the MDR1 transcript. In addition, the high levels of both MDR1 and MRP3 mRNA expression in MPNST may help to explain the poor response of this tumor to anticancer‐drugs.