[Treatment of gastric cancer: current state and future prospect].
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Biomedical subjects
Publications and source records attributed to Shinya Oda.
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Hepatocyte growth factor (HGF) stimulates cell motility as well as mitotic activity of cells. High concentrations of HGF or overexpression of its cellular receptor c-Met in cancer have been reported. We analyzed the expression status of c-Met immunohistochemically in 76 cases of human esophageal cancer. Overexpression of c-Met was noted at a considerably high frequency. Intriguingly, c-Met overexpression was frequent in a specific type of cell nest formation in tumors, i.e., the small nest type, in which tumors form small, dispersed cell nests. Further immunohistochemical analyses using serial sections revealed a striking coincidence between overexpression of c-Met and its transcriptional factor, Ets-1. Overexpression of c-Met and Ets-1 was statistically more frequent in small nest type tumors. The close correlation in expression status between Ets-1 and c-Met was also confirmed using 6 established human esophageal cancer cell lines. In addition, cells that expressed high levels of Ets-1 and c-Met exhibited an extremely motile phenotype by HGF stimulation in vitro. The presence of HGF in tissue sections was confirmed using similar immunohistochemical approaches. These observations suggest that in human esophageal cancer cells the transcriptional factor Ets-1 upregulates the expression of c-Met and, consequently, confers on cells a highly motile phenotype leading to a specific form of tumor development.
BACKGROUND AND OBJECTIVES: An overexpression of c-erbB2 has been reported to be associated with a poor clinical outcome in breast cancer, however, its prognostic value remains controversial especially in patients with node negative breast cancer, and regarding the estrogen receptor (ER) status. METHODS: Immunohistochemical staining for c-erbB2 was performed on the primary breast cancer from 698 Japanese patients with a mean follow-up duration of 54 months. RESULTS: The c-erbB2 expression was positive in 120 (17.2%) of 698 cases, which inversely correlated with the ER status. Both univariate and multivariate analyses indicated the c-erbB2 expression to be a significant prognostic factor for the disease-free survival (DFS) and overall survival (OS), while the same effect was also seen in the patient groups with node negative as well as node positive breast cancer. A univariate analysis also indicated a subgroup with the positive c-erbB2 and negative ER to have both a worse DFS and OS than the other subgroups. The patients with positive c-erbB2 had a significantly worse DFS and OS than the patients with negative c-erbB2 in all patient groups stratified according to the adjuvant therapies, while the prognostic significance of c-erbB2 on DFS was also found in the patients with the node negative breast cancer who received adjuvant tamoxifen alone. CONCLUSIONS: The c-erbB2 expression is an independent significant factor for breast cancer and the prognostic significance remains in the node negative as well as node positive breast cancer, while the same effect was also found in all subgroups stratified according to the adjuvant therapies. In addition, the combination of c-erbB2 and ER made it possible to identify the subgroup with the worst clinical outcome.
An epidermal growth factor receptor (EGFR) has been reported to be associated with a poor clinical outcome in breast cancer, while its prognostic value remains controversial. Immunohistochemical staining for EGFR was performed on frozen sections of primary breast cancer from 1029 patients with a mean follow-up duration of 46 months. EGFR was positive in 277 (26.9%) of 1029 cases which inversely correlated with the estrogen receptor (ER) status. A univariated analysis indicated that EGFR had a significant prognostic value in both the disease free survival (DFS) and the overall survival (OS), while the same effect was also found in node negative as well as node positive breast cancer. A multivariate analysis indicated that EGFR was an independently significant prognostic factor for DFS (p = 0.0174) and OS (p = 0.0105) in all patients, but that EGFR demonstrated a prognostic significance only for DFS (p = 0.0241) in node negative and only for OS (p = 0.0333) in node positive breast cancer. When all patients were stratified for EGFR and ER, a multivariate analysis indicated that the combination of EGFR(+)/ER(-) was an independently significant factor for both DFS and OS in node negative as well as node positive breast cancer. In conclusion, the prognostic value of EGFR was demonstrated by a multivariate analysis in a large series of breast cancer patients, but the value of EGFR was somewhat insufficient to achieve statistical significance for both DFS and OS in the subgroups divided by nodal status. On the other hand, the prognostic value of combination of EGFR and ER was sufficient to achieve statistical significance based on a multivariate analysis for both DFS and OS in the subgroups of node negative as well as node positive breast cancer patients.
BACKGROUND: The growth of solid tumors and the formation of metastases depend on angiogenesis. Both tumor cells and host cells secrete a variety of factors to stimulate angiogenesis. METHODS: We investigated the expression of angiogenic factors in gastric cancer in vitro and in vivo. RESULTS: The expression of one of the angiogenic factors, vascular endothelial growth factor antigen, in gastric cancer cells can thus serve as a pertinent predictive factor for hematogenous invasion or metastasis, in addition to having prognostic value. The presence of micrometastasis in bone marrow was closely related to vascular endothelial growth factor positivity and microvessel density in the primary gastric cancer. In in vivo experiments antiangiogenic agents with cytotoxic anticancer drugs formed a highly effective modulator combination for the treatment of the Lewis lung carcinoma against primary and metastatic disease. CONCLUSIONS: Antiangiogenic agents may thus be valuable for long-term administration to maintain tumor dormancy because drug resistance does not develop, and these agents have a sustained effect. As a target, antiangiogenic therapy may therefore be potentially able to prolong survival time of patients with gastric cancer.
Analyses of microsatellite instability have been prevalent, particularly in the field of oncology. However, the literature on this subject is diverse. The discrepancies may derive from methodological problems in the conventional techniques used for analysis. Problems include low quantitativity in the detection systems, inaccurate migration in electrophoresis, and Taq polymerase-mediated modifications of polymerase chain reaction products. Indeed, use of a new fluorescent technique where these problems have been overcome has elucidated various intriguing and previously unrecognized aspects of microsatellite instability in human cancers. Patterns of microsatellite changes observed in various human cancers can be classified into 2 subtypes, those showing relatively small changes within 6 base pairs (type A) and those exhibiting drastic changes over 8 base pairs (type B). Although type A microsatellite instability has been connected to defective mismatch repair phenotype, the relationship between type B microsatellite instability and defective mismatch repair phenotype remains unclear. Nevertheless, as symbolized in cases of hereditary nonpolyposis colorectal cancer, connections between type B microsatellite instability and familial predisposition have been suggested in some cancers. The molecular background of type B microsatellite changes warrants particular attention.
BACKGROUND: Various studies have analyzed the relationships between new biological parameters and DNA ploidy for human cancer. However, the biological significance of DNA ploidy remains unclear, since there have so far been few studies analyzing DNA ploidy in relation to the combination of multiple such biological parameters. METHODS: Samples for the analysis of DNA ploidy, estrogen receptor (ER), progesterone receptor (PgR), p53 protein and epidermal growth factor receptor (EGFR) were prepared from the same frozen specimens of 498 primary breast cancers. DNA ploidy was determined by flow cytometry, while ER and PgR were determined by an enzyme immunoassay. Both p53 protein and EGFR were determined by immunohistochemical analyses. RESULTS: Aneuploidy was significantly correlated with the absence of ER, the absence of PgR, the positivity of p53 protein and the positivity of EGFR, and it was also significantly correlated with the combination of the absence of ER and PgR and the combination of the positivity of p53 protein and EGFR. A deviation in the four parameters was defined as the absence of ER, the absence of PgR, the positivity of p53 protein or the positivity of EGFR. As the number of deviations of these four biological parameters increased, the incidence of aneuploidy increased significantly (p < 0.0001). Multivariate analysis also indicated that deviation of two, three or all four parameters were significant factors for DNA ploidy, while the p value decreased and the odds ratio increased as the number of deviations of the four biological parameters increased. CONCLUSIONS: DNA aneuploidy based on flow cytometric analysis reflects the accumulation of deviations in the four biological parameters investigated in the present study. The two facts that DNA aneuploidy reflects the accumulation of the aggressiveness of these biological parameters and that DNA aneuploidy consisted of heterogeneous characteristics which were represented by the deviation of each biological parameter should be taken into consideration when selecting treatment strategies for breast cancer.
The criteria for familial gastric cancer are as follows: 1) there should be at least 3 relatives with gastric cancer, 2) one should be a first-degree relative of the other 2, 3) at least 2 successive generations should be affected, 4) at least 1 should be diagnosed before age 50, and 5) other familial tumors should be excluded. There are two types of familial gastric cancer, diffuse type and intestinal type, of which the genetic background seems to be differ. In 1998, an autosomal dominant syndrome of diffuse gastric cancer was reported with germline mutations in the E-cadherin gene and has been identified in approximately 14 families and 50 individuals worldwide. In addition, an inherited mutation in mismatch repair (MMR) genes was found in hereditary non-polyposis colorectal cancer (HNPCC) in 1993. Since there is high frequency microsatellite instability found in familial gastric cancer patients, vigorous efforts have been made to find abnormalities in MMR genes of familial gastric cancer patients. However, to date, there has been little progress in detecting MMR gene mutations in familial gastric cancer patients. It is clinically most important to obtain a detailed family history to identify familial gastric cancer patients. At present, prophylactic total gastrectomy for familial gastric cancer is under careful consideration.