Hidetoshi Kawaguchi

Grb7 signal transduction protein mediates metastatic progression of esophageal carcinoma.

We have previously reported the association of tumor cell invasion with expression of growth factor receptor‐bound protein 7 (Grb7). This molecule contains a Src homology 2 (SH2) domain and shares structural homology with a cell migration molecule designated Mig‐10 found in Caenorhabditis elegans. In the present study, Grb7 expression was analyzed in human esophageal carcinomas with or without metastatic spread. The Grb7 protein was overexpressed in 14 of 31 esophageal carcinomas as compared to the adjacent normal mucosa (45%) and this finding was significantly correlated with the presence of lymph node metastases. We also identified that Grb7 protein in esophageal carcinoma cells was phosphorylated on tyrosine by epidermal growth factor as well as attachment to extracellular matrix proteins including fibronectin. Such fibronectin‐dependent phosphorylation of Grb7 was regulated by integrin signaling that leads to the interaction with focal adhesion kinase protein. Furthermore, ectopic expression of a Grb7‐SH2 dominant‐negative fragment inhibited the fibronectin‐dependent phosphorylation of endogenous Grb7, and reduced migration of esophageal carcinoma cells into fibronectin. Our results suggest a role of Grb7 mediated signal transduction in generation of an invasive cell phenotype against extracellular matrix, and thus contributes to metastatic progression of human esophageal carcinoma. J. Cell. Physiol. 183:411–415, 2000.

Y-box binding protein-1 (YB-1) promotes cell cycle progression through CDC6-dependent pathway in human cancer cells

Y-box binding protein-1 (YB-1) plays pivotal roles in acquisition of global drug resistance and cell growth promotion through transcriptional activation of genes for both drug resistance and growth factor receptors. In this study, we investigated whether YB-1 is involved in regulation of the cell cycle and cell proliferation of human cancer cells. Treatment with YB-1 siRNA caused a marked suppression of cell proliferation and expression of a cell cycle related gene, CDC6 by cancer cells. Of cell cycle of cancer cells, S phase content was specifically reduced by knockdown of YB-1. The overexpression of CDC6 abrogated this inhibition of both cell proliferation and S phase entry. ChIP assay demonstrated that YB-1 binds to a Y-box located in the promoter region of the CDC6 gene. Expression of cyclin D1, CDK1 and CDK2 was also reduced with increased expression of p21(Cip1) and p16(INK4A) when treated with YB-1 siRNA. Furthermore, the nuclear YB-1 expression was significantly associated with the level of CDC6 nuclear expression in patients with breast cancer. In conclusion, YB-1 plays an important role in cell cycle progression at G1/S of human cancer cells. YB-1 thus could be a potent biomarker for tumour growth and cell cycle in its close association with CDC6.

Concurrent overexpression of ETS-1 and C-met correlates with a phenotype of high cellular motility in human esophageal cancer

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.

Prognostic factors in patients with submucosal carcinoma of the oesophagus

To clarify the prognostic factors in patients with submucosal carcinoma of the oesophagus, we examined the results of surgical treatment for 78 cases over the last decade. The clinicopathological factors including age, sex, location of the tumour, length of the tumour, histological differentiation, subclassification of depth, lymphatic or blood vessel invasion, intramural metastasis and lymph node metastasis were all analysed. Then the correlation between these factors and prognosis was investigated. As a result, significant differences were observed in the survival rates between the groups regarding lymphatic vessel invasion (P = 0.0003), intramural metastasis (P = 0.0051) and lymph node metastasis (P = 0.0026). According to a multivariate analysis, intramural metastasis (P = 0.0038, relative risk 9.17), vessel invasion (P = 0.0033, relative risk 6.25) and lymph node metastasis (P = 0.0187, relative risk 3.62) were found to be independent prognostic factors. The prognosis of the patients with at least one of these factors was significantly poorer than that without. The five-year survival rate of the patients without these factors was as good as that with mucosal carcinoma of the oesophagus. Based on our findings, vessel invasion, intramural metastasis and lymph node metastasis are thus considered to be significant prognostic factors in patients with submucosal carcinoma of the oesophagus.

Proliferative activity of cancer cells in front and center areas of carcinoma in situ and invasive sites of esophageal squamous‐cell carcinoma

Intraepithelial carcinoma contiguous with invasive squamous‐cell carcinoma is a conspicuous feature of esophageal cancer. However, whether the mechanism of intraepithelial spreading is due to cell proliferation or field carcinogenesis has yet to be clarified. This study investigated the mechanism of intraepithelial spreading by measuring the cell proliferative activity using argyrophilic nucleolar organizer region (AgNOR) and proliferating cell nuclear antigen (PCNA)‐positive cell counting. We examined the AgNOR number and PCNA‐positive ratio (PCNA ratio) in the center and outer edge of intraepithelial carcinoma and in the center and deep margin of invasive squamous‐cell carcinoma of the esophagus in 50 specimens from 18 cases of esophageal squamous‐cell carcinoma concomitant with contiguous intraepithelial carcinoma. The proliferative activity was thus found to differ between the normal epithelium and cancerous lesions (p < 0.001), between intraepithelial carcinoma and invasive cancer (p < 0.001) and between deep margin and center areas of invasive cancer (p < 0.005). On the other hand, such activity was observed to be similar in the center and outer edge of the intraepithelial spread. These findings suggest that cell proliferation is the main mechanism of tumor progression at the invasive site of cancer, whereas in intraepithelial carcinomatous areas, “field carcinogenesis” or a paracrine mechanism, and not cell proliferation, is thought to be the cause of intraepithelial spread of esophageal cancer. These results therefore support the concept of field carcinogenesis. Int. J. Cancer 78:149–152, 1998.© 1998 Wiley‐Liss, Inc.

CYFRA 21-1 determination in patients with esophageal squamous cell carcinoma

While there are reports that CYFRA 21‐1 is a useful tumor marker, to our knowledge the clinical utility of this marker to detect recurrences for squamous cell carcinoma of the esophagus has not been addressed.

PROGNOSTIC SIGNIFICANCE OF LYMPHOCYTE INFILTRATION FOLLOWING PREOPERATIVE CHEMORADIOTHERAPY AND HYPERTHERMIA FOR ESOPHAGEAL CANCER

PURPOSE Lymphocyte infiltration (LI) around cancerous lesions is an important immune response. The purpose of this study is to evaluate the prognostic significance of LI after preoperative treatment for esophageal cancer. METHODS AND MATERIALS Preoperative chemoradiotherapy (CR therapy), either bleomycin 30 mg or cisplatin 120 mg/m(2) plus radiation 30 Gy, was performed on 51 cases with esophageal cancer, while hyperthermo-chemoradiotherapy (HCR therapy) was also indicated in 71 cases. Using resected specimens, both the histopathologic effectiveness and degree of LI to cancerous lesions were evaluated. RESULTS The incidences of the cases in which preoperative treatment was effective were 56% and 92.3% in LI (-) and LI (++) group (p < 0.05). The presence of LI resulted in favorable prognosis; the 5-year survival rates of LI (++) and LI (+) patients were 75.5% and 46.1%, both of which were significantly better than LI (-) (27.8%, p < 0.05 and p < 0.01, respectively). Especially among cases whose preoperative treatment was moderately effective, a multivariate analysis revealed LI to be a favorable prognostic factor independent of other clinicopathologic factors (p = 0.0171). Regarding the preoperative treatment, the incidence of LI (++) was higher in the HCR group (16.9%) than in the CR group (2.0%, p < 0.01). CONCLUSIONS LI appears to be a prognostic predictor after preoperative CR therapy while, in addition, simultaneous hyperthermia may stimulate LI in cases with esophageal cancer.

Alcohol consumption and cigarette smoking in relation to high frequency of p53 protein accumulation in oesophageal squamous cell carcinoma in the Japanese.

We investigated levels of p53 protein expression in Japanese patients with oesophageal squamous cell carcinoma. A significantly larger proportion of heavy alcohol drinkers and cigarette smokers was evident in the p53-positive group. The combination of drinking and smoking was associated with a high frequency of p53 protein accumulation.

Family aggregation of carcinoma of the hypopharynx and cervical esophagus : Special reference to multiplicity of cancer in upper aerodigestive tract

The role of family history in the multiple occurrence of cancer in the upper aerodigestive tract (UADT) remains unclear. The family histories of close relatives were examined in 167 patients with either hypopharyngeal or cervical esophageal cancer (PhCe cancer) and in 167 control subjects with benign diseases. The odds ratio for PhCe cancer was 2.6 in relation to family history of UADT cancers. Based on the family histories of close relatives, 167 cases with PhCe cancer were divided into 3 groups (Group I, 18 cases with a family history of UADT cancer; Group II, 37 cases with a family history of other cancers; Group III, 112 cases with no family history of any cancers). The mean age of the cases in group I was 59.4, which was younger than in group III (64.2). Second primary squamous‐cell carcinomas in the UADT were more frequently recognized in group I (39%) than in group III (11%). However, no differences were observed in the smoking and drinking habits of male patients between each group. These results thus suggest that a family history of UADT cancers appears to be associated with the multiple occurrence of UADT cancers as well as the development of PhCe cancer. Int. J. Cancer 76:468‐471, 1998.© 1998 Wiley‐Liss, Inc.

p53 protein accumulation in multiple oesophageal squamous cell carcinoma: relationship to risk factors.

To clarify mechanisms involved in the carcinogenesis of multiple oesophageal squamous cell carcinoma, the expression of p53 protein in 46 lesions surgically excised from 13 Japanese patients was investigated immunohistochemically and the relation of p53 protein accumulation to the patient’s history of alcohol consumption and cigarette smoking was analyzed. p53 protein accumulation was observed in 13 main lesions, that is in 6 (85.7%) of 7 subjects with a history of heavy drinking and smoking, but only in 1 (16.7%) of 6 with no such history (Fisher’s exact test, p = 0.025). As regards the 46 lesions, p53 protein accumulation was evident in 22 (88.0%) of 25 lesions of the high-risk patients, but in 7 (33.3%) of 21 lesions of the other subjects (Fisher’s exact test, p < 0.001). p53 protein accumulation was similarly recognized in all oesophageal lesions in 5 of 7 high-risk patients. Thus, use of both alcohol and cigarettes is clearly associated with a high frequency of p53 protein accumulation in multiple oesophageal squamous cell carcinoma present at the same time. These findings are considered to support the concept of field carcinogenesis of the oesophagus.