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Colorectal cancer (CRC), diet and p53
A656 AGA ABSTRACTS G2703 CHARACTERISTICS OF METACHRONOUS COLORECTAL ADENOMAS DURING LONG-TERM FOLLOW-UP, G. Nusko. U. Mansmann, U. Partzsch, Th. Kirchner, E.G. Hahn. Dept. of Medicine I, Dept. of Pathology, University of Erlangen, Institute of Medical Statistics, Free University of Berlin, Germany
Background: After resection of colorectal adenomas patients have to be followed-up in regular intervals. The aim of the study was to describe changes of metachronous adenomas found during several follow-ups. Methods: At the Erlangen Registry of Colorectal Polyps a total of 1159 patients have been followed-up prospectively between 1978 to 1996. ~2 testing was performed to determine differences of size, histological type, multiplicity and grade of dysplasia found in metachronous adenomas during five consecutive surveillance examinations. Results: At the initial examination 5241 (76.7%) adenomas were tubular and 1596 (23.3%) were tnbulovillous or villous. At the first follow-up 1095 (83.8%) were tubular and 212 (16.2%) tubulovillous or villous. Tubular adenomas were significantly more often found at follow-up (p<0.0001). At initial examination 4962 (72.9%) were small (10 ram) and 1842 (27.1%) large adenomas. At first follow-up 1167 (90.2%) were small and 127 (9.8%) large adenomas. Small adenomas were found significantly more often at surveillance (p<0.0001). Initially 6440 (92.3%) adenomas had low-grade and 536 (7.7%) high-grade dysplasia. At first follow-up 1284 (97.9%) had lowgrade and 27 (2.1%) high-grade dysplasia. Adenomas found at follow-up had significantly more often low-grade dysplasia (p<0.0001). At the initial examination 1610 (26.4%) adenomas were found solitary and 4497 (73.6%) as multiple lesions. At first follow-up 345 (26.3%) were single and 966 (73.7%) were multiple adenomas. There was no significant difference in the number of adenomas found initially and during surveillance. During the subsequent four fotlow-up examinations no differences were found between first and further follow-ups. The significant differences in size, histological type and degree of dysplasia were found between the initial examination and the first follow-up only. Conclusions: Metachronous adenomas are significantly more often small tubular adenomas having merely low-grade dysplasia compared with the initial findings. During long term surveillance no additional differences will be found. The patients are put back to the original of adenoma/dysplasiacarcinoma sequence. Multiplicity of adenomas can be considered as a personally constant proliferation parameter with no significant changes during surveillance. • G2704 RISK RELATED SURVEILLANCE OF PATIENTS WITH COLORECTAL ADENOMAS. G. Nusko. U. Mansmann, U. Partzsah, Th. Kirchner, E.G. Hahn. Dept. of Medicine I, Dept. of Pathology, University of Edangen, Institute of Medical Statistics, Free University of Berlin, Germany Background: After resection of colorectal adenomas patients have to be followed-up in regular intervals. Different surveillance recommendations have been scheduled recently. The aim of the study was to determine risk related surveillance according to patient and adenoma characteristics. Methods: At the Erlangen Registry of Cnlorectal Polyps a total of 1159 patients have been followed-up prospectively between 1978 to 1996, Statistical analysis including Kaplan-Meier survival estimation, logrank test and multivariate cox regression analysis were performed to determine surveillance intervals for the detection of advanced adenomas (> 10 mm or high-grade dysplasia or carcinoma). Results: Univariate analysis (logrank testing) revealed that patients having initial tubular adenomas (N= 694) and patients with tubulovillous/villous (N=465) adenomas had a different risk. For patients with tubular adenomas only significant prognostic factors were history of parental colorectal carcinoma (p=0.036), adenoma size (p<0.0001), multiplicity (p=0.007) and an interactive effect of size and gender (p--0.0(O). Cox regression analysis revealed different time intervals for advanced metachronons adenomas. A group of very low-risk consisted of men without parental history of colorectal carcinoma having only a single small ( 10 mm) tubular adenoma. 10 % of these patients developed within 10 years after initial resection advanced metachronous lesions. Patients having a parental history of colorectal carcinoma and also men without parental history having large tubular adenomas have to be considered as a highrisk group. 10 % of them will develop advanced lesions within 2 years. An intermediate risk was found for men with multiple small tubular adenomas and women with single tubular adenomas of each size having advanced adenomas after 6 years. After 3 years patients who had tubulovillous or villous adenomas will have advanced metachronous lesions and also women with multiple tubular adenomas of each size. Conclusions: Patients who had tubulovillous or villous adenomas at initial examination should be followed-up at 3 years intervalsl Patients who had tubular adenomas have to be divided into different subgroups of risk taking in account the parental history of colorectal carcinomas, gender, adenoma size and multiplicity. High-risk patients should be followed-up at 2 years, low-risk patients at 10 years and intermediate-risk patients at 6 years saving costs and unnecessary examinations.
GASTROENTEROLOGYVol. 114, No. 4 • G2705 COLORECTAL CANCER (CRC), DIET AND p53. A. Obrador, V. Moreno, D. Bantista, E. Cabeza, R. Canet, E. Benito, X. Bosch, J. Costa. Dept of Gastroenterology and Pathology, Son Dureta Hospital (Palma), Spain, Epidemiology Unit and Cancer Registry, Majorca, Spain, Epidemiology and Cancer Registry, Institut Catal~ d'Oncologia, Duran i Reynals Hospital Barcelona Spain, Dept of Pathology, University School of Medicine, New Haven, Connecticut Over the past few years, our knowledge on the basic carcinogenic mechanisms of CRC cancer has improved substantially. Among several genetic abnormalities described in these patients, the abnormal expression of the oncogenes p53 and Ki-ras appear to play a relevant role. On the other hand, diet seems to be a modulator to the expression of Ki-ras in these patients (Bantista et al. Cancer Epidem Bit & Prey, 1997), but its relationship to p53 is much less understood. This study was designed to investigated the relationship between diet and the expression of p53. We designed a case-control study in which patients (and controls) were recruited from a previous epidemiological study (Benito et al. Int. J. Cancer 1992). In 106 of these patients, we were able to evaluate the expression of p53 in paraffin-embedded tumor amples. We then divided patients according to the presence or absence of overexpression of p53, and we compared the food group intake and the proportion of each nutrient in both groups. In addition, we compared these nutritional parameter in controls and in each of these two groups of patients. This latter analysis was also performed for the presence or absence of a mutated Ki-ras genotype. All results were adjusted for age, sex, number of meals, caloric intake and other potential confounding factors, such as smoking habits or tumor staging. Results. Sixty two of the 106 patients included (58.5%) showed overexpression of p53. We found that cruciferous intake significantly decreases the overexpression of p53. The latter was also true for the intake of vitamins B1 and B12. The results previously reported on the relationship between Ki-ras mutation and diet (Bantista et al. Cancer Epidem Bit &Prev, 1997) were not modified when the expression of p53 was also taken in to account. Condnsions. These results indicate that: (1) by incorporating molecular markers, epidemiological studies can provide a better insight on the mechanisms of carcinogenesis in patients with colorectal cancer; (2) of all the variables assessed in this study, we found that only a few of them were significantly related to overexpression of p53; and, (3) the relationship between diet and mutation of Ki-ras does not appear to be significantly influenced by the overexpression of p53. • G2706 EFFECTS OF HELICOBACTER PYLORI ON CELL CYCLE, PROLIFERATION AND DNA CONTENT OF GASTRIC EPITHELIAL CELLS IN VITRO. B. Obs0, S. Wagner2, I. Sobak-Klocke 2, W. BeiP. qnstitute of General Pharmacology and 2Department of Gastroenterology and Hepatology, Medizinisahe Hochschule Hannover, D-30625 Hannover, Germany.
H. pylori infection is recognized as a risk factor for gastric adenocarcinoma, however, the underlying pathogenic mechanisms are unknown. Changes in cell cycle and proliferation play a critical role in carcinogenesis. Therefore we investigated the effects of a water soluble extract of H. pylori on proliferation, cell cycle and DNA content of gastric epithelial cells in vitro. Methods: H. pylori was grown in BHI plus 10 % FBS under microaerophilic conditions. A water soluble extract was prepared according to the method of Kurose et al. (Gastroenterology 1994; 107:70 - 79). Gastric epithelial cell lines AGS and HM02 were incubated for 24 hours with H. pylori water extract. EGF was used as a mitogenic stimulus and camptothecin served as an inductor of apoptosis. Cell proliferation was assessed by measuring 3H-thymidine incorporation and DNA content was assayed with Hoechst 33258 stain. Cell cycle was analyzed by FACS scan with propinmiodid and a Fluorescein conjugated PCNA-antibody. Results: H. pylori extract caused a dose-dependent increase in 3H-thymidine incorporation in both AGS and HM02 cells. Partial characterization of this stimulatory activity revealed a proteinacious factor with a molecular weight of more than 100 KD which was present in both VacA/CagA positive and VacAJCagA negative strains. The increase in 3H-thymidine incorporation was not associated with changes in cell cycle nor with an increase in DNA content. In contrast incubation with the mitogen EGF resulted in a higher rate of cell proliferation, a 60 % increase in DNA content and FACS analysis showed a significantly higher rate of ceils in S and G2/M phases of the cell cycle. Camptothecin caused a 40 % decrease in DNA content and a 3-fold increase of apoptotic ceils measured by FACS. Conclusion: Incubation of gastric epithelial cells with H. pylori induces enhanced 3H-thymidine incorporation without changes in cell cycle and DNA content. These findings suggest that H. pylori causes DNA damage which is accompanied by compensatory enhanced DNA repair. This research was supported by a grant of the Deutsche Forschungsgemeinsehaft (Sonderforschungsbereich 280, Teilprojekt A7).
Background: After resection of colorectal adenomas patients have to be followed-up in regular intervals. The aim of the study was to describe changes of metachronous adenomas found during several follow-ups. Methods: At the Erlangen Registry of Colorectal Polyps a total of 1159 patients have been followed-up prospectively between 1978 to 1996. ~2 testing was performed to determine differences of size, histological type, multiplicity and grade of dysplasia found in metachronous adenomas during five consecutive surveillance examinations. Results: At the initial examination 5241 (76.7%) adenomas were tubular and 1596 (23.3%) were tnbulovillous or villous. At the first follow-up 1095 (83.8%) were tubular and 212 (16.2%) tubulovillous or villous. Tubular adenomas were significantly more often found at follow-up (p<0.0001). At initial examination 4962 (72.9%) were small (10 ram) and 1842 (27.1%) large adenomas. At first follow-up 1167 (90.2%) were small and 127 (9.8%) large adenomas. Small adenomas were found significantly more often at surveillance (p<0.0001). Initially 6440 (92.3%) adenomas had low-grade and 536 (7.7%) high-grade dysplasia. At first follow-up 1284 (97.9%) had lowgrade and 27 (2.1%) high-grade dysplasia. Adenomas found at follow-up had significantly more often low-grade dysplasia (p<0.0001). At the initial examination 1610 (26.4%) adenomas were found solitary and 4497 (73.6%) as multiple lesions. At first follow-up 345 (26.3%) were single and 966 (73.7%) were multiple adenomas. There was no significant difference in the number of adenomas found initially and during surveillance. During the subsequent four fotlow-up examinations no differences were found between first and further follow-ups. The significant differences in size, histological type and degree of dysplasia were found between the initial examination and the first follow-up only. Conclusions: Metachronous adenomas are significantly more often small tubular adenomas having merely low-grade dysplasia compared with the initial findings. During long term surveillance no additional differences will be found. The patients are put back to the original of adenoma/dysplasiacarcinoma sequence. Multiplicity of adenomas can be considered as a personally constant proliferation parameter with no significant changes during surveillance. • G2704 RISK RELATED SURVEILLANCE OF PATIENTS WITH COLORECTAL ADENOMAS. G. Nusko. U. Mansmann, U. Partzsah, Th. Kirchner, E.G. Hahn. Dept. of Medicine I, Dept. of Pathology, University of Edangen, Institute of Medical Statistics, Free University of Berlin, Germany Background: After resection of colorectal adenomas patients have to be followed-up in regular intervals. Different surveillance recommendations have been scheduled recently. The aim of the study was to determine risk related surveillance according to patient and adenoma characteristics. Methods: At the Erlangen Registry of Cnlorectal Polyps a total of 1159 patients have been followed-up prospectively between 1978 to 1996, Statistical analysis including Kaplan-Meier survival estimation, logrank test and multivariate cox regression analysis were performed to determine surveillance intervals for the detection of advanced adenomas (> 10 mm or high-grade dysplasia or carcinoma). Results: Univariate analysis (logrank testing) revealed that patients having initial tubular adenomas (N= 694) and patients with tubulovillous/villous (N=465) adenomas had a different risk. For patients with tubular adenomas only significant prognostic factors were history of parental colorectal carcinoma (p=0.036), adenoma size (p<0.0001), multiplicity (p=0.007) and an interactive effect of size and gender (p--0.0(O). Cox regression analysis revealed different time intervals for advanced metachronons adenomas. A group of very low-risk consisted of men without parental history of colorectal carcinoma having only a single small ( 10 mm) tubular adenoma. 10 % of these patients developed within 10 years after initial resection advanced metachronous lesions. Patients having a parental history of colorectal carcinoma and also men without parental history having large tubular adenomas have to be considered as a highrisk group. 10 % of them will develop advanced lesions within 2 years. An intermediate risk was found for men with multiple small tubular adenomas and women with single tubular adenomas of each size having advanced adenomas after 6 years. After 3 years patients who had tubulovillous or villous adenomas will have advanced metachronous lesions and also women with multiple tubular adenomas of each size. Conclusions: Patients who had tubulovillous or villous adenomas at initial examination should be followed-up at 3 years intervalsl Patients who had tubular adenomas have to be divided into different subgroups of risk taking in account the parental history of colorectal carcinomas, gender, adenoma size and multiplicity. High-risk patients should be followed-up at 2 years, low-risk patients at 10 years and intermediate-risk patients at 6 years saving costs and unnecessary examinations.
GASTROENTEROLOGYVol. 114, No. 4 • G2705 COLORECTAL CANCER (CRC), DIET AND p53. A. Obrador, V. Moreno, D. Bantista, E. Cabeza, R. Canet, E. Benito, X. Bosch, J. Costa. Dept of Gastroenterology and Pathology, Son Dureta Hospital (Palma), Spain, Epidemiology Unit and Cancer Registry, Majorca, Spain, Epidemiology and Cancer Registry, Institut Catal~ d'Oncologia, Duran i Reynals Hospital Barcelona Spain, Dept of Pathology, University School of Medicine, New Haven, Connecticut Over the past few years, our knowledge on the basic carcinogenic mechanisms of CRC cancer has improved substantially. Among several genetic abnormalities described in these patients, the abnormal expression of the oncogenes p53 and Ki-ras appear to play a relevant role. On the other hand, diet seems to be a modulator to the expression of Ki-ras in these patients (Bantista et al. Cancer Epidem Bit & Prey, 1997), but its relationship to p53 is much less understood. This study was designed to investigated the relationship between diet and the expression of p53. We designed a case-control study in which patients (and controls) were recruited from a previous epidemiological study (Benito et al. Int. J. Cancer 1992). In 106 of these patients, we were able to evaluate the expression of p53 in paraffin-embedded tumor amples. We then divided patients according to the presence or absence of overexpression of p53, and we compared the food group intake and the proportion of each nutrient in both groups. In addition, we compared these nutritional parameter in controls and in each of these two groups of patients. This latter analysis was also performed for the presence or absence of a mutated Ki-ras genotype. All results were adjusted for age, sex, number of meals, caloric intake and other potential confounding factors, such as smoking habits or tumor staging. Results. Sixty two of the 106 patients included (58.5%) showed overexpression of p53. We found that cruciferous intake significantly decreases the overexpression of p53. The latter was also true for the intake of vitamins B1 and B12. The results previously reported on the relationship between Ki-ras mutation and diet (Bantista et al. Cancer Epidem Bit &Prev, 1997) were not modified when the expression of p53 was also taken in to account. Condnsions. These results indicate that: (1) by incorporating molecular markers, epidemiological studies can provide a better insight on the mechanisms of carcinogenesis in patients with colorectal cancer; (2) of all the variables assessed in this study, we found that only a few of them were significantly related to overexpression of p53; and, (3) the relationship between diet and mutation of Ki-ras does not appear to be significantly influenced by the overexpression of p53. • G2706 EFFECTS OF HELICOBACTER PYLORI ON CELL CYCLE, PROLIFERATION AND DNA CONTENT OF GASTRIC EPITHELIAL CELLS IN VITRO. B. Obs0, S. Wagner2, I. Sobak-Klocke 2, W. BeiP. qnstitute of General Pharmacology and 2Department of Gastroenterology and Hepatology, Medizinisahe Hochschule Hannover, D-30625 Hannover, Germany.
H. pylori infection is recognized as a risk factor for gastric adenocarcinoma, however, the underlying pathogenic mechanisms are unknown. Changes in cell cycle and proliferation play a critical role in carcinogenesis. Therefore we investigated the effects of a water soluble extract of H. pylori on proliferation, cell cycle and DNA content of gastric epithelial cells in vitro. Methods: H. pylori was grown in BHI plus 10 % FBS under microaerophilic conditions. A water soluble extract was prepared according to the method of Kurose et al. (Gastroenterology 1994; 107:70 - 79). Gastric epithelial cell lines AGS and HM02 were incubated for 24 hours with H. pylori water extract. EGF was used as a mitogenic stimulus and camptothecin served as an inductor of apoptosis. Cell proliferation was assessed by measuring 3H-thymidine incorporation and DNA content was assayed with Hoechst 33258 stain. Cell cycle was analyzed by FACS scan with propinmiodid and a Fluorescein conjugated PCNA-antibody. Results: H. pylori extract caused a dose-dependent increase in 3H-thymidine incorporation in both AGS and HM02 cells. Partial characterization of this stimulatory activity revealed a proteinacious factor with a molecular weight of more than 100 KD which was present in both VacA/CagA positive and VacAJCagA negative strains. The increase in 3H-thymidine incorporation was not associated with changes in cell cycle nor with an increase in DNA content. In contrast incubation with the mitogen EGF resulted in a higher rate of cell proliferation, a 60 % increase in DNA content and FACS analysis showed a significantly higher rate of ceils in S and G2/M phases of the cell cycle. Camptothecin caused a 40 % decrease in DNA content and a 3-fold increase of apoptotic ceils measured by FACS. Conclusion: Incubation of gastric epithelial cells with H. pylori induces enhanced 3H-thymidine incorporation without changes in cell cycle and DNA content. These findings suggest that H. pylori causes DNA damage which is accompanied by compensatory enhanced DNA repair. This research was supported by a grant of the Deutsche Forschungsgemeinsehaft (Sonderforschungsbereich 280, Teilprojekt A7).