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Increased expression of ezrin is related with the metastatic potential of human pancreatic adenocarcinoma
A764 AGA ABSTRACTS
4104 LONG·TERM FOLLOW·UP OF PATIENTS WITH LOW-GRADE GASTRIC MALT LYMPHOMA AFTER ERADICATION OF REL-
ICOBACTER PYLORI. In Sung Song, You Sun Kim, II Ju Choi, Joo Sung Kim, Hyun Chae Jung, Chung Yong Kim, Seoul National Univ, Seoul, South Korea. Objective: High remission rates of low-grade B-cell gastric MALT lymphoma have been reported after cure of H. pylori infection. Although p16 hypermethylation was frequently found in patients with MALT lymphoma, there has been no report about the association of H. pylori infection and p16 hypermethylation. We performed this prospective study to evaluate the long-term outcome of patients with low-grade gastric MALT lymphoma after H. pylori eradication. We also investigated the detection of P16 hypermethylation in gastric MALT lymphoma and its change of expression after remission. Methods: We prospectively enrolled twenty patients with H. pylori-positive low-grade gastric MALT lymphoma (stage lEI)' For diagnosis of MALT lymphoma, we used the histologic scoring of Wotherspoon. Patients were treated with amoxicillin, clarithromycin and omeprazole for I week to eradicate H. pylori. Follow-up endoscopic examinations with multiple biopsies were performed at regular intervals. Methylation-specific PCR (MSP) method was used for the serial detection of p16 hypermethylation. Results: H. pylori infection was cured in 19 patients and one has been received secondary quadruple treatment. The median follow-up for the 20 patients is currently 18 months. Eighteen patients achieved complete remission and their median duration of remission is 16 months. One has relapsed of MALT lymphoma for two times with and without H. pylori reinfection. pl6 hypermethylation was detected at 58% (7/12) and its expression tended to be decrease after achievement of remission. In 3 patients who had long-term remission, p16 hypermethylation was disappeared. Conclusion: Complete remission of low-grade gastric MALT lymphoma after eradication of H. pylori infection could be maintained in long-term period. However, long-term follow-up is needed because MALT lymphoma can recur with or without H. pylori reinfection. Further studies are warranted to be investigated a role of p16 hypermethylation in the pathogenesis of gastric MALT lymphoma.
4105 EVALUATION OF RISKS FOR STOMACH CANCER (ERISC): CROSS-SECTIONAL FINDINGS AND THE COHORT-STUDY PROTOCOL. Haruhiko Yoshida, Yutaka Yamaji, Masao Akanuma, Yoshihiro Hirata, Yuzo Mitsuno, Shin Maeda, Keiji Ogura, Makoto Okamoto, Takao Kawabe, Yasushi Shiratori, Masao Omata, Univ of Tokyo, Tokyo, Japan. Background!Aims: Stomach cancer is the leading cause of cancer death in Japan, claiming more than 50,000 victims annually. Although H. pylori is indicated to have causative relation to the cancer, diagnosis of infection alone may not be useful in distinguishing high risk groups in Japan where H. pylori infection is highly prevalent. The ERISC study was begun on March 1, 1998 to seek practical indicators of risks for stomach cancer. Cross-Sectional Findings: Serum anti-CagA antibody (in-house ELISA) and pepsinogen VII were measured in 80 Japanese patients with stomach cancer and sex-and age-matched controls. Odds ratios for stomach cancer calculated by conditional logistic regression were 11.00 (95% CI; 3.37 35.87) for anti-CagA seropositivity (>25 AU), 5.14 (2.29 - 11.56) for high anti-CagA titer (> 100 AU), 2.09 (1.02 - 4.29) for positive pepsinogen index (PI<70 ng/ml and Pl/PII<3.0), and 4.17 (1.71 - 10.16) for strongly positive index (PI<30 ng/ml and Pl/PII<2.0). A combination of high anti-CagA titer and/or strongly positive pepsinogen index had 79% sensitivity and 71% specificity for the morbidity of stomach cancer. Discussion: Both anti-CagA seropositivity, representing infection with virulent strains, and positive pepsinogen index, representing mucosal atrophy, were associated with stomach cancer. 'False positive'cases may in reality be at a high risk of future cancer development. To validate this prospectively, we have started the ERISC cohort study, where subjects of gastroduodenal endoscopy at our department consenting to follow-up are consecutively enrolled (1,600 as of October 31, 1999). The estimated observation of 20,000 person-years required to detect a risk factor with a risk ratio of 10 will be attained in 6 years.
4106 EFFECTS OF H. PYLORI ERADICATION ON THE EXPRESSION OF CYCLIN D2 AND P27 IN GASTRIC INTESTINAL METAPLASIA. Jun Yu, Wai K. Leung, Minnie Yy Go, Francis K1Chan, Kar F. To, Joseph Jy Sung, Chinese Univ of Hong Kong, Hong Kong, Hong Kong. Background Cyclins and cyclin-dependent kinase inhibitors (CDKI) play an important and counter-regulatory role in the control of cell cycle transitiions. Over-expression of cyclins (D,E) and suppression of CDKI (p21, p27) have been reported in gastric cancers. Since H. pylori (HP)
GASTROENTEROLOGY Vol. 118, No.4
infection is recongized as a stimulant of gastric epithelial proliferation and an important cause of gastric cancer, we hypothesized that in chronic HP infection, expression of cyclins and CDKI are altered. Aim To study the expression of Cyclin D2 and p27 in gastric epithelium before and after eradication of HP. Patients and Method Endoscopic gastric biopsies obtained from 22 HP infected patients were studied. 12 patients showed extensive intestinal metaplasia (1M) and 10 showed chronic gastritis only. Each patients had 2 sets of serial gastric biopsies before and at one-year after eradication of HP. Expression of cyclin D2 and p27 were assessed by immuno-chemistry. Sections were scored by 2 independent investigatiors by a pre-determined scoring scale based on the precentage of cells stained positive (O=absence of staining, 1=<5%, 2=5-25%, 3=25-50% and 4=>50% cell stained positive). Results Expression of cyclin D2 was significantly reduced after eradication of HP in both 1M and Gastritis groups. Patients with chronic gastritis have normal expression of p27 which did not change with treatment. Reduced p27 expression was detected in 6 out of 12 patients with 1M which were fully restored to normal at one year after HP eradication. Conclusion HP infection induces reversible changes on cyclin D2 and p27 expressions of gastric mucosa containing 1M. Alterations in cell cycle regulators appears to be an early phenomenon in HP associated gastric carcinogenic process.
cyclin 02
p27
1M before Rx
1M after Rx
P
Gastritis before Rx
Gastritis after Rx
P
2(0-3) 2.5(1-4)
0(0-2) 4(4)
0001 0.014
2(1-4) 4(4)
0.5 (0-2) 4(4)
003 >0.05
Paired samples (before and after HP eradication) of1M and Gastritis group were compared using Wilcoxon signed rank lest
4107 INCREASED EXPRESSION OF EZRIN IS RELATED WITH THE METASTATIC POTENTIAL OF HUMAN PANCREATIC ADENO· CARCINOMA. Naoaki Akisawa, Isao Nishimori, Takeshi Iwamura, Michael A. Hollingsworth, Saburo Onishi, Kochi Med Sch, Nankoku, Kochi, Japan; Miyazaki Med ColI, Miyazaki, Japan; Eppley Cancer Institute, Omaha, NE. Background: Ezrin is a membrane-cytoskeleton crosslinker protein that is a member of the ERM (ezrin/radixin/moesin) family. Ezrin binds adhesion molecules such as CD43, CD44, ICAM-l, and ICAM-2, which are implicated in cell migration and metastasis. Ezrin is expressed by many tumor cell lines, however, little is known about the function of ezrin in tumorigenesis and metastasis. Aims: To evaluate the role of ezrin in the metastatic event of cancer cells, we studied the relationship between expression of ezrin and metastatic potential of pancreatic adenocarcinomas. Methods: Total RNAs and cell Iysates were extracted from 16 pancreatic adenocarcinoma cell lines, including SUIT-2 cell and its 6 sublines that were previously reported to have different metastatic potentials. The expression levels of ezrin in those samples were examined by Northern blot and Western blot analyses. The expression level of CD44 protein was also examined. Results: All of pancreatic adenocarcinoma cell lines studied showed various expression levels of ezrin mRNA and protein; there was corelation between the protein and mRNA expression levels in each cell line. Among SUIT-2 and its sublines, S2-CP9 and S2-VPI0 with very highly metastatic potential showed stronger levels of ezrin mRNA and protein expression than SUIT-2 cells (approximately 3 times and 5-6 times higher in mRNA and protein expression levels, respectively) and other cell lines. There was no relationship between the of ezrin expression levels and the differentiation grades of the cell lines. There was no correlation between ezrin and CD44 expression in these cell lines. Conclusions: These results suggest that ezrin, one of membrane-cytoskeleton crosslinker proteins, has some role in the metastatic process of pancreatic adenocarcinomas.
4108 NOVEL MECHANISMS OF ANGIOGENESIS INDUCED BY PROSTAGLANDINS (PGS) IN COLON CARCINOGENESIS. Hiromi Bamba, Shinichi Ota, Akira Kato, Chiaki Kawamoto, Kenji Fujiwara, Fukashi Matsuzaki, Saitama Med Sch, Kawagoe, Japan; Saitama Med Sch, Iruma, Japan. We previously reported that cyclooxygenase-Z (COX-2) was predominantly expressed in macrophages of sporadic human colonic adenomas (Int. J. Cancer 83: 470, 1999). The role of PGs produced by COX-2expressing macrophages in colon carcinogenesis have not yet been elucidated. In addition, the role of peroxisome proliferator-activated receptor')'
4104 LONG·TERM FOLLOW·UP OF PATIENTS WITH LOW-GRADE GASTRIC MALT LYMPHOMA AFTER ERADICATION OF REL-
ICOBACTER PYLORI. In Sung Song, You Sun Kim, II Ju Choi, Joo Sung Kim, Hyun Chae Jung, Chung Yong Kim, Seoul National Univ, Seoul, South Korea. Objective: High remission rates of low-grade B-cell gastric MALT lymphoma have been reported after cure of H. pylori infection. Although p16 hypermethylation was frequently found in patients with MALT lymphoma, there has been no report about the association of H. pylori infection and p16 hypermethylation. We performed this prospective study to evaluate the long-term outcome of patients with low-grade gastric MALT lymphoma after H. pylori eradication. We also investigated the detection of P16 hypermethylation in gastric MALT lymphoma and its change of expression after remission. Methods: We prospectively enrolled twenty patients with H. pylori-positive low-grade gastric MALT lymphoma (stage lEI)' For diagnosis of MALT lymphoma, we used the histologic scoring of Wotherspoon. Patients were treated with amoxicillin, clarithromycin and omeprazole for I week to eradicate H. pylori. Follow-up endoscopic examinations with multiple biopsies were performed at regular intervals. Methylation-specific PCR (MSP) method was used for the serial detection of p16 hypermethylation. Results: H. pylori infection was cured in 19 patients and one has been received secondary quadruple treatment. The median follow-up for the 20 patients is currently 18 months. Eighteen patients achieved complete remission and their median duration of remission is 16 months. One has relapsed of MALT lymphoma for two times with and without H. pylori reinfection. pl6 hypermethylation was detected at 58% (7/12) and its expression tended to be decrease after achievement of remission. In 3 patients who had long-term remission, p16 hypermethylation was disappeared. Conclusion: Complete remission of low-grade gastric MALT lymphoma after eradication of H. pylori infection could be maintained in long-term period. However, long-term follow-up is needed because MALT lymphoma can recur with or without H. pylori reinfection. Further studies are warranted to be investigated a role of p16 hypermethylation in the pathogenesis of gastric MALT lymphoma.
4105 EVALUATION OF RISKS FOR STOMACH CANCER (ERISC): CROSS-SECTIONAL FINDINGS AND THE COHORT-STUDY PROTOCOL. Haruhiko Yoshida, Yutaka Yamaji, Masao Akanuma, Yoshihiro Hirata, Yuzo Mitsuno, Shin Maeda, Keiji Ogura, Makoto Okamoto, Takao Kawabe, Yasushi Shiratori, Masao Omata, Univ of Tokyo, Tokyo, Japan. Background!Aims: Stomach cancer is the leading cause of cancer death in Japan, claiming more than 50,000 victims annually. Although H. pylori is indicated to have causative relation to the cancer, diagnosis of infection alone may not be useful in distinguishing high risk groups in Japan where H. pylori infection is highly prevalent. The ERISC study was begun on March 1, 1998 to seek practical indicators of risks for stomach cancer. Cross-Sectional Findings: Serum anti-CagA antibody (in-house ELISA) and pepsinogen VII were measured in 80 Japanese patients with stomach cancer and sex-and age-matched controls. Odds ratios for stomach cancer calculated by conditional logistic regression were 11.00 (95% CI; 3.37 35.87) for anti-CagA seropositivity (>25 AU), 5.14 (2.29 - 11.56) for high anti-CagA titer (> 100 AU), 2.09 (1.02 - 4.29) for positive pepsinogen index (PI<70 ng/ml and Pl/PII<3.0), and 4.17 (1.71 - 10.16) for strongly positive index (PI<30 ng/ml and Pl/PII<2.0). A combination of high anti-CagA titer and/or strongly positive pepsinogen index had 79% sensitivity and 71% specificity for the morbidity of stomach cancer. Discussion: Both anti-CagA seropositivity, representing infection with virulent strains, and positive pepsinogen index, representing mucosal atrophy, were associated with stomach cancer. 'False positive'cases may in reality be at a high risk of future cancer development. To validate this prospectively, we have started the ERISC cohort study, where subjects of gastroduodenal endoscopy at our department consenting to follow-up are consecutively enrolled (1,600 as of October 31, 1999). The estimated observation of 20,000 person-years required to detect a risk factor with a risk ratio of 10 will be attained in 6 years.
4106 EFFECTS OF H. PYLORI ERADICATION ON THE EXPRESSION OF CYCLIN D2 AND P27 IN GASTRIC INTESTINAL METAPLASIA. Jun Yu, Wai K. Leung, Minnie Yy Go, Francis K1Chan, Kar F. To, Joseph Jy Sung, Chinese Univ of Hong Kong, Hong Kong, Hong Kong. Background Cyclins and cyclin-dependent kinase inhibitors (CDKI) play an important and counter-regulatory role in the control of cell cycle transitiions. Over-expression of cyclins (D,E) and suppression of CDKI (p21, p27) have been reported in gastric cancers. Since H. pylori (HP)
GASTROENTEROLOGY Vol. 118, No.4
infection is recongized as a stimulant of gastric epithelial proliferation and an important cause of gastric cancer, we hypothesized that in chronic HP infection, expression of cyclins and CDKI are altered. Aim To study the expression of Cyclin D2 and p27 in gastric epithelium before and after eradication of HP. Patients and Method Endoscopic gastric biopsies obtained from 22 HP infected patients were studied. 12 patients showed extensive intestinal metaplasia (1M) and 10 showed chronic gastritis only. Each patients had 2 sets of serial gastric biopsies before and at one-year after eradication of HP. Expression of cyclin D2 and p27 were assessed by immuno-chemistry. Sections were scored by 2 independent investigatiors by a pre-determined scoring scale based on the precentage of cells stained positive (O=absence of staining, 1=<5%, 2=5-25%, 3=25-50% and 4=>50% cell stained positive). Results Expression of cyclin D2 was significantly reduced after eradication of HP in both 1M and Gastritis groups. Patients with chronic gastritis have normal expression of p27 which did not change with treatment. Reduced p27 expression was detected in 6 out of 12 patients with 1M which were fully restored to normal at one year after HP eradication. Conclusion HP infection induces reversible changes on cyclin D2 and p27 expressions of gastric mucosa containing 1M. Alterations in cell cycle regulators appears to be an early phenomenon in HP associated gastric carcinogenic process.
cyclin 02
p27
1M before Rx
1M after Rx
P
Gastritis before Rx
Gastritis after Rx
P
2(0-3) 2.5(1-4)
0(0-2) 4(4)
0001 0.014
2(1-4) 4(4)
0.5 (0-2) 4(4)
003 >0.05
Paired samples (before and after HP eradication) of1M and Gastritis group were compared using Wilcoxon signed rank lest
4107 INCREASED EXPRESSION OF EZRIN IS RELATED WITH THE METASTATIC POTENTIAL OF HUMAN PANCREATIC ADENO· CARCINOMA. Naoaki Akisawa, Isao Nishimori, Takeshi Iwamura, Michael A. Hollingsworth, Saburo Onishi, Kochi Med Sch, Nankoku, Kochi, Japan; Miyazaki Med ColI, Miyazaki, Japan; Eppley Cancer Institute, Omaha, NE. Background: Ezrin is a membrane-cytoskeleton crosslinker protein that is a member of the ERM (ezrin/radixin/moesin) family. Ezrin binds adhesion molecules such as CD43, CD44, ICAM-l, and ICAM-2, which are implicated in cell migration and metastasis. Ezrin is expressed by many tumor cell lines, however, little is known about the function of ezrin in tumorigenesis and metastasis. Aims: To evaluate the role of ezrin in the metastatic event of cancer cells, we studied the relationship between expression of ezrin and metastatic potential of pancreatic adenocarcinomas. Methods: Total RNAs and cell Iysates were extracted from 16 pancreatic adenocarcinoma cell lines, including SUIT-2 cell and its 6 sublines that were previously reported to have different metastatic potentials. The expression levels of ezrin in those samples were examined by Northern blot and Western blot analyses. The expression level of CD44 protein was also examined. Results: All of pancreatic adenocarcinoma cell lines studied showed various expression levels of ezrin mRNA and protein; there was corelation between the protein and mRNA expression levels in each cell line. Among SUIT-2 and its sublines, S2-CP9 and S2-VPI0 with very highly metastatic potential showed stronger levels of ezrin mRNA and protein expression than SUIT-2 cells (approximately 3 times and 5-6 times higher in mRNA and protein expression levels, respectively) and other cell lines. There was no relationship between the of ezrin expression levels and the differentiation grades of the cell lines. There was no correlation between ezrin and CD44 expression in these cell lines. Conclusions: These results suggest that ezrin, one of membrane-cytoskeleton crosslinker proteins, has some role in the metastatic process of pancreatic adenocarcinomas.
4108 NOVEL MECHANISMS OF ANGIOGENESIS INDUCED BY PROSTAGLANDINS (PGS) IN COLON CARCINOGENESIS. Hiromi Bamba, Shinichi Ota, Akira Kato, Chiaki Kawamoto, Kenji Fujiwara, Fukashi Matsuzaki, Saitama Med Sch, Kawagoe, Japan; Saitama Med Sch, Iruma, Japan. We previously reported that cyclooxygenase-Z (COX-2) was predominantly expressed in macrophages of sporadic human colonic adenomas (Int. J. Cancer 83: 470, 1999). The role of PGs produced by COX-2expressing macrophages in colon carcinogenesis have not yet been elucidated. In addition, the role of peroxisome proliferator-activated receptor')'