Seiichi Tamai

The correlation between cytoplasmic overexpression of epidermal growth factor receptor and tumor aggressiveness: poor prognosis in patients with pancreatic ductal adenocarcinoma.

Objectives: Recent studies have shown that some growth factor receptors with tyrosine kinase activity, eg, the epidermal growth factor receptor (EGFr) and the c-erbB-2 (HER-2) oncoprotein, are associated with aggressive biologic behavior of various cancer cell types. We examined the clinicopathological significance of the expression and localization of EGFr and HER-2 in both invasive and intraductal components of ductal adenocarcinomas of the pancreas. Methods: Tissue samples from 76 archival cases of pancreatic ductal adenocarcinoma were immunohistochemically analyzed for both membrane and cytoplasmic overexpression of EGFr and HER-2 oncoprotein. The rate of incidence between the invasive and intraductal components was analyzed and then their correlation with tumor differentiation and patient prognosis was analyzed. Results: Cytoplasmic EGFr overexpression was more frequent in invasive components (47 of 76, 62%) than in intraductal components (19 of 76, 25%), while membrane EGFr overexpression was more frequent in intraductal components (41 of 76, 54%) than in invasive components (11 of 76, 14%). The membrane HER-2 overexpression was also more frequent in intraductal components (15 of 76, 20%) than in invasive components (2 of 76, 3%), but the incidence of cytoplasmic HER-2 overexpression did not differ between intraductal components (12 of 76, 16%) and invasive components (8 of 76, 11%). The cytoplasmic EGFr overexpression in invasive components was more frequent in grade 3 group (32 of 33, 97%) than in grade 2 (15 of 32, 47%) and grade 1 groups (0 of 10, 0%) (P < 0.001). Patients with adenocarcinoma with cytoplasmic EGFr overexpression showed shorter overall survival than those with adenocarcinoma without cytoplasmic EGFr overexpression (P = 0.02). Conclusion: It is suggested that the cytoplasmic overexpression of EGFr plays a significant role in the progression of pancreatic ductal adenocarcinoma, especially in the invasion and acquisition of aggressive clinical behavior. Both membrane and cytoplasmic expression of HER-2 showed no significant correlation between tumor differentiation and poor survival.

Loss of ARID1A protein expression occurs as an early event in ovarian clear-cell carcinoma development and frequently coexists with PIK3CA mutations

ARID1A is a recently identified tumor suppressor gene that is mutated in ∼50% of ovarian clear-cell carcinomas. This mutation is associated with loss of ARID1A protein expression as assessed by immunohistochemistry. The present study aimed at determining the timing of the loss of ARID1A protein expression during the development of ovarian clear-cell carcinoma and assessing its relevance in correlation to PIK3CA gene mutations. A total of 42 clear-cell carcinoma cases with adjacent putative precursor lesions (endometriosis-associated carcinoma cases (n=28) and (clear-cell) adenofibroma-associated carcinoma cases (n=14)) were selected and subjected to immunohistochemical analysis for ARID1A protein expression and direct genomic DNA sequencing of exons 9 and 20 of the PIK3CA gene. ARID1A immunoreactivity was deficient in 17 (61%) of the 28 endometriosis-associated carcinomas and 6 (43%) of the 14 adenofibroma-associated carcinomas. Among the precursor lesions adjacent to the 23 ARID1A-deficient carcinomas, 86% of the non-atypical endometriosis (12 of 14) and 100% of the atypical endometriosis (14 of 14), benign (3 of 3), and borderline (6 of 6) clear-cell adenofibroma components were found to be ARID1A deficient. In contrast, in the 19 patients with ARID1A-intact carcinomas, all of the adjacent precursor lesions retained ARID1A expression regardless of their types and cytological atypia. Analysis of 22 solitary endometrioses and 10 endometrioses distant from ARID1A-deficient carcinomas showed that all of these lesions were diffusely immunoreactive for ARID1A. Among the 42 clear-cell carcinomas, somatic mutations of PIK3CA were detected in 17 (40%) tumors and majority (71%) of these were ARID1A-deficient carcinomas. These results suggest that loss of ARID1A protein expression occurs as a very early event in ovarian clear-cell carcinoma development, similar to the pattern of PIK3CA mutation recently reported by our group, and frequently coexists (not mutually exclusive) with PIK3CA mutations.

PIK3CA mutation is an early event in the development of endometriosis‐associated ovarian clear cell adenocarcinoma

Clear cell adenocarcinoma (CCA), a highly lethal histological subtype of ovarian carcinoma, is a type of human cancer with a high frequency of activating mutations in the PIK3CA gene. In this study, we aimed to determine how these mutations contribute to tumour development of CCAs. Exons 9 and 20 of the PIK3CA gene were analysed by direct genomic DNA sequencing of 23 CCAs with synchronous putative precursor lesions (ie endometriosis adjacent to carcinoma, with or without cytological atypia) and their mutational statuses were compared. Somatic mutations of the PIK3CA gene were detected in 10/23 (43%) carcinomas and in all cases the type of mutation was H1047R in the kinase domain. The identical H1047R mutation was also detected in the coexisting endometriotic epithelium, adjacent to the CCAs, in nine of ten (90%) cases. Moreover, in six of the nine lesions, the H1047R mutation was identified even in the endometrioses lacking cytological atypia. These findings provide evidence that mutations of the PIK3CA gene occur in the putative precursor lesions of CCA, strongly suggesting that they are very early events in tumourigenesis, probably initiating the malignant transformation of endometriosis. A specific kinase inhibitor to mutated PIK3CA may potentially be an effective therapeutic reagent against these carcinomas. Copyright

Correlation of KIT and EGFR overexpression with invasive ductal breast carcinoma of the solid‐tubular subtype, nuclear grade 3, and mesenchymal or myoepithelial differentiation

Although KIT and EGFR overexpressions are reported to occur in breast cancer, their pathological significance is still unclear. We examined KIT, EGFR, and c‐erbB‐2 overexpressions immunohistochemically in 150 cases of surgically resected breast cancer and their correlation with the histological type and grade and mesenchymal and/or myoepithelial immunophenotype of primary tumors. To facilitate the analysis, we constructed a tissue microarray comprising 2‐mm diameter tissues cored from the representative tissue block of each tumor. KIT, EGFR, and c‐erbB‐2 overexpressions were detected in 15 (10%), 12 (8%), and 23 (15%), respectively. The KIT was more frequent in the group comprising comedo‐type ductal carcinoma in situ and invasive ductal carcinomas (IDCs) of the solid‐tubular subtype than in the group of other histological types (P = 0.027), and the EGFR was more frequent in IDCs of solid‐tubular type than in other histological types (P < 0.05). KIT and EGFR overexpressions were correlated with nuclear grade 3 (P = 0.0095 and 0.0005) and tended to be concurrent (P = 0.005). KIT overexpression was correlated with vimentin and S‐100 expression (P = 0.003 and P = 0.005), and EGFR overexpression was correlated with S100 expression (P = 0.0001). These correlations with grade and mesenchymal/myoepithelial markers were not observed for c‐erbB‐2 overexpression. KIT and EGFR appeared to be indicators of high‐grade breast carcinoma groups that often contain the carcinomas with mesenchymal and/or myoepithelial differentiation, which are distinct from the group with c‐erbB‐2 overexpression. (Cancer Sci 2005; 96: 48 –53)

Actinin-4 gene amplification in ovarian cancer: a candidate oncogene associated with poor patient prognosis and tumor chemoresistance

Actinin-4, an isoform of non-muscular α-actinin, enhances cell motility by bundling the actin cytoskeleton. We previously reported a prognostic implication of high immunohistochemical expression of actinin-4 protein in ovarian cancers. Chromosomal gain or amplification of the 19q12–q13 region has been reported in ovarian cancer. We hypothesized that the actinin-4 (ACTN4) gene might be a target of the 19q12–q13 amplicon and play an essential role of ovarian cancer progression. In total, 136 advanced-stage ovarian cancers were investigated for the copy number of the ACTN4 gene on chromosome 19q13, using fluorescence in situ hybridization, and the correlation of the ACTN4 copy number with actinin-4 protein immunoreactivity and major clinicopathological factors was investigated. A higher copy number (≧4 copies) of the ACTN4 gene was detected in 29 (21%) cases and was highly associated with the intensity of actinin-4 immunoreactivity (P<0.0001), a high histological tumor grade (P=0.030), a clear-cell adenocarcinoma histology (P=0.012), resistance to first-line chemotherapies (P=0.028), and poor patient outcome (P=0.0011). Univariate analyses using the Cox regression model showed that a higher ACTN4 gene copy number was able to predict patient outcome more accurately than high actinin-4 immunoreactivity (relative risk: 2.48 vs 1.55). Multivariate analysis showed that a higher copy number of the ACTN4 gene and the degree of residual disease were independent prognostic factors for overall patient survival. The actinin-4 gene may be a target of the 19q amplicon, acting as a candidate oncogene, and serve as a predictor of poor outcome and tumor chemoresistance in patients with advanced-stage ovarian cancers.

Gene amplification and protein overexpression of MET are common events in ovarian clear-cell adenocarcinoma: their roles in tumor progression and prognostication of the patient

The aim of this study was to assess protein overexpression and gene copy number alterations of MET in ovarian clear-cell adenocarcinoma, and to assess its potential as a novel therapeutic target. Ninety cases of clear-cell adenocarcinoma were analyzed for MET protein overexpression and copy number alterations of the MET gene by immunohistochemistry and brightfield double in situ hybridization, respectively. In addition, 101 cases of the non-clear-cell type ovarian carcinomas at advanced stages were also evaluated for comparison. MET overexpression was assigned when complete membrane staining with moderate or strong intensity was observed in at least 10% of the tumor cells examined. Double in situ hybridization was determined as positive when the tumor exhibited high-level polysomy (≥4 copies in ≥40% of tumor cells) or MET gene amplification. MET overexpression was detected in 20 of 90 clear-cell adenocarcinomas (22%) and none of 111 non-clear-cell type ovarian carcinomas. Double in situ hybridization was positive in 21 of 89 informative clear-cell adenocarcinomas (24%) and only 3 non-clear-cell type ovarian carcinomas (3%). In the whole population, true amplification of the MET gene was detected only in the clear-cell adenocarcinoma histology (five cases, 6%). In clear-cell adenocarcinomas, double in situ hybridization positivity was highly correlated with the presence of MET overexpression and a poorly differentiated histology of tumors (P=0.0105 and 0.00038, respectively). For the patients with clear-cell adenocarcinomas, MET overexpression, as well as advanced clinical stage and the poorly differentiated histology of tumors, was identified as an independent unfavorable prognostic factor for overall survival. In conclusion, among ovarian carcinomas, the amplification of the MET proto-oncogene is highly selective and commonly occurs in clear-cell adenocarcinoma. MET could serve as a biomarker for the prognostication of patients with clear-cell adenocarcinoma and tumor progression, and has potential as a novel therapeutic target for this carcinoma.

PIK3CA mutations and loss of ARID1A protein expression are early events in the development of cystic ovarian clear cell adenocarcinoma

Somatic mutations of PIK3CA and ARID1A are the most common genetic alterations observed in ovarian clear cell adenocarcinomas (CCA). In a previous report, we showed that PIK3CA gene mutations and loss of ARID1A expression occur early during the development of CCA. In the present study, using direct genomic DNA sequencing for exons 9 and 20 of PIK3CA and immunohistochemistry for ARID1A protein expression, we analyzed the association of these molecular alterations with various clinicopathological parameters in a total of 90 cases of primary ovarian CCA, including 42 previously examined cases. The presence of PIK3CA mutations, identified in 34 (39%) of the 88 informative cases, was significantly associated with a grossly cystic tumor, the presence of adjacent endometriosis, prominent papillary architecture of tumor growth, the presence of hyalinized and mucoid stroma, and the absence of clear cell adenofibroma components (P < 0.05, each). There was no significant association of PIK3CA mutations with other clinical variables, such as age, clinical stage, or clinical outcome of the patients. The intensity of immunoreactivity for ARID1A was assigned as negative, weakly positive, and strongly positive in 44%, 22%, and 33% of tumors, respectively. Compared to tumors immunoreactive for ARID1A, ARID1A-negative tumors were significantly associated with the presence of adjacent endometriosis (P = 0.025), but there was no statistically supported association with other examined clinicopathological parameters. Compared with CCAs strongly positive for ARID1A, CCAs negative for ARID1A more frequently harbor PIK3CA mutations (P = 0.013). PIK3CA gene mutations and ARID1A immunohistochemistry lacked prognostic significance. These data further support the idea that these molecular alterations occur as very early events during tumor development of ovarian CCA.

Green Tea Consumption and Serum Malondialdehyde-Modified LDL Concentrations in Healthy Subjects

Objective: Green tea was shown to inhibit LDL oxidation, platelet aggregation, and matrix metalloproteinases (MMPs) activities in vitro. We tried to elucidate whether or not green tea consumption may have these effects in vivo, which may be protective against atherosclerotic disease. Methods: We measured serum malondialdehyde-modified LDL (MDA-LDL) concentrations and urine 8-epi-prostaglandin (PG) F2α in 22 healthy male nonsmokers. They drank 7 cups/day of water for 2 weeks and drank 7 cups/day of green tea for the next 2 weeks. Regarding platelet aggregation, plasma thromboxane B2 (TXB2) and 6-keto-PGF1α concentrations and ex vivo platelet aggregation were evaluated. Plasma MMP-2 and -9 concentrations were also measured. Results: Of the 22 subjects, 20 had been in the habit of drinking green tea before the study. Plasma catechins concentrations significantly decreased at the end of the water period and then increased at the end of the green tea period. Although no change in plasma LDL-cholesterol concentrations (110 ± 33 vs. 113 ± 28 mg/dL, p = NS) was found, MDA-LDL concentrations (84 ± 45 vs. 76 ± 40 IU/L, p < 0.05) and the ratio of MDA-LDL/LDL-cholesterol (0.74 ± 0.21 vs. 0.65 ± 0.20, p < 0.02) significantly decreased at the end of the green tea period. However, no significant changes were observed in urine 8-epi-PGF2α concentrations, in platelet aggregation, nor in plasma TXB2, 6-keto-PGF1α or MMP concentrations. Conclusion: Daily consumption of green tea decreased serum MDA-LDL concentrations, but it had no significant effects on platelet aggregation, platelet TX production or plasma MMPs concentrations. Our results suggest that green tea consumption may inhibit LDL oxidation in vivo.

Lung carcinoma with rhabdoid cells: a clinicopathological study and survival analysis of 14 cases

Lung carcinoma with rhabdoid cells: a clinicopathological study and survival analysis of 14 cases

Clear cell adenocarcinoma associated with clear cell adenofibromatous components: a subgroup of ovarian clear cell adenocarcinoma with distinct clinicopathologic characteristics.

We occasionally encountered clear cell adenofibromatous (CCAF) components coexisting in the ovarian clear cell adenocarcinoma (CCA). To reveal the clinicopathologic significance of CCAF components in CCA, we classified 67 cases of surgically resected CCA into CCA with and without CCAF components [CCAF(+) and (−) groups], and compared clinicopathologic parameters, that is, patient age, clinical stage, the degree of optimal cytoreduction, patient outcome, histologic grade and Ki-67 labeling index of the CCA, and the presence of endometriosis, between these 2 groups. Fourteen cases (21%) and 53 cases were classified as CCAF(+) and CCAF(−) groups, respectively. Of these 14 CCAF(+) cases, the CCAF components with atypia were observed adjacent to the CCAF components without atypia in 10, and adjacent to the obvious CCAs in 13 cases. In comparison with the CCAF(−) group, the CCAF(+) group showed a higher frequency of histologically low-grade tumors [93% (13 of 14) vs. 43% (23 of 53), P=0.0027], a lower Ki-67 labeling index (mean 35.9% vs. 44.0%, P=0.0492), and better patient prognosis (5-year survival 78.8% vs. 49.3%, P=0.0277). Endometriosis was much less frequent in the CCAF(+) group than in the CCAF(−) group [14.7% (2 of 14) vs. 67.9% (36 of 53), P=0.00096]. Multivariate analysis identified only optimal cytoreduction as independent favorable prognostic factor. These results suggest that CCAF besides endometriosis is associated with the development of CCA, and that the CCAF(+) group may be a distinct subgroup of CCA with less aggressive biologic behavior.