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The significance of duodenal polyps: A five-year review of histological features and natural history
Gastrointestinal Oncology A605
April 1998 pathway, particularly mevalonate, famesol and geranylgeraniol (GG) in the lovastatin-induced apoptosis. Lovastatin induced changes including apoptosis were completely inhibited by mevalonate 100 laM and GG 1 laM but only partially by farnesol 50 ~tM, suggesting that inhibition of famesylation of ras is not the major mechanism of action of lovastatin and that some other proteins which are geranylgeranylated are the predominant targets. To determine whether the effect of lovastatin were entirely due to inhibition of activity of the various isoprenylated G-proteins, we treated the IEC-18 ceils with lovastatin and cycloheximide. Cycloheximide completely prevented the Iovastatin-induced changes in the IEC-18 cells, showing that new protein synthesis is required not only for apoptosis but also for the lovastatin induced changes in the cell structure and adhesion. To conclude, lovastatin alters cell morphology and induces loss of cell adhesion and p53 dependent (or p53 sensitive) apoptosis in IEC-18 cells independent of ras expression. The effects of lovastatin are predominantly due to inhibition of geranylgeranylation (rather than farnesylation) and require synthesis of certain (presently unidentified) proteins which may mediate these effects. • G2487 METHYLENE BLUE STAINING FOR THE ENDOSCOPIC DIAGNOSIS OF INTESTINAL METAPLASIA IN THE STOMACH. D. Halperin, R. Belmonte, L. Sanchez, A. Mohar, J. Guarner, R. Herrera, Parsonnet. J. San Cristobal de las Casas and Mexico City, Mexico, Atlanta, GA and Stanford, CA. Staining of the gastric mucosa with methylene blue (MB) has been suggested as a useful method for determining presence and extent of intestinal metaplasia (IM) at gastroscopy. We evaluated the sensitivity, specificity and predictive power of MB staining in a population with very high prevalence of gastric cancer and preneoplastic lesions. Methods- Two endoscopists carried out a total of 148 gastroscopies as part of a study on gastric preneoplastic lesions in Chiapas, Mexico. Following application of a solution of acetyl cysteine (Mucomyst ®) to dissolve gastric mucus, methylene blue (0.01% solution) was applied through a spray catheter to the gastric mucosa. The stomach was then washed with approximately 200 ml of water to eliminate non-specific staining of mucus. The endoscopists described the gastric mucosa as: diffuse staining, focal staining and nonstaining. A total of seven biopsies of the gastric mucosa were taken from stained and unstained areas. Biopsies were evaluated by two pathologists blinded to the results of the MB staining using the revised Sydney Classification for gastritis. Results- Diffuse MB staining was noted at endoscopy in 65 subjects, focal staining in 69 subjects and no staining in only 14 subjects. By histology, intestinal metaplasia was identified in 72 (49%) of the 148 patients; 54(36%) had complete IM, 22 (15%) had incomplete IM (4 patients had both types). For all intestinal metaplasia, the sensitivity and specificity of staining were 96.05% and 15.28%, respectively. The predictive power positive and negative were 54.48% and 78.57%. When analyzed by IM type and/or by type of staining (diffuse vs. focal), there was no improvement in test characteristics. Even after gaining considerable experience, the endoscopists found the procedure to be cumbersome and the staining results subjective. Discussion. In a population with high gastric cancer rates, we did not find methylene blue staining at the time of gastroscopy to be a useful diagnostic test for IM due to the high number of false positives and the subjectivity of the procedure. G2488
GERMLINE MUTATION OF THE PTEN GENE IN JAPANESE PATIENTS WITH COWDEN DISEASE. N.Hamano. T.Okada, A.Suzuki, Y.Takeda, H.Mabuchi, 2nd Department of Internal Medicine, Kanazawa University, Ishikawa, Japan. Background and Aim: Cowden disease, also known as multiple hamartoma syndrome, is an autosomal cancer syndrome with a high risk of breast and thyroid cancer. Recently, the tumor suppressor gene PTEN, encoding a putative protein tyrosine or dual specificity phnsphatase and located at chromosome 10q23.3, was reported as the gene causing Cowden disease. In this study, we analyzed germline mutations of the PTEN gene in Japanese patients with Cowden disease. Subjects: Three Japanese patients with Cowden disease and their families. The patients' clinical manifestations are shown below. Patient Sex Age
Mucocutaneous Thyroid Breast Intestine Others Face Oral Skin + + + adenoma cancer osteoma
case 1
M
41
case 2
M
28
+
+
+
case 3
F
48
+
+
+
adenoma gyneco- polyps scoliosis mastia adenoma cancer polyps pulmonary hamartornas
Methods: Genomic DNA was isolated from the whole blood of the patients and their families. Exons of the PTEN gene were amplified by PCR. Sequencing of the exons was performed using non-radioactive method. Results: 1) In case 2, sequencing exon 7 of the PTEN gene revealed a nonsense mutation, CGA to TGA: Arg233Stop. Presence of the same mutation in Western patients with Cowden disease was previously reported,
so we conclude this is pathogenic. Because his parents displayed neither mutation of the PTEN gene nor clinical manifestations of Cowden disease, it would appear to have occured de novo. 2) In case 3, sequencing exon 8 of the PTEN gene revealed a missense mutation, CGA to CTA: Arg335Leu, which we could not identify in normal controls. To our knowledge, this mutation have not been previously reported. Conclusion: Germline mutations in the PTEN gene in Japanese patients with Cowden disease were identified. G2489
CORRELATIONS BETWEEN p53 OVEHEXPRESSION, SERUM ANTIBODIES AND GENE MUTATION IN COLORECTAL CANCER. P. Hammel 1, K. Leroy-Viard 2, M.T. Chaumette 2, J. Villandy 3, M.C. Falzone 2, D. Rouillard 3, Y. Remvikos 3, T. Soussi3. 1Gastroenterology Departement, H6pital Beanjon, 92118 Clichy; 2Pathology Departement, H6pital Henri Mondor, 94010 Cr6teil, 3Institut Curie, 75005 Paris, France. Background: only half of colorectal cancers with p53 gene mutations seem to elicit serum antibodies (p53-Ab) in response to intratumoral p53 protein accumulation. Aim: Our study was designed to compare cellular events (p53 protein expression and gene mutations) to the presence of circulating p53-Ab. Patients and Methods: Thirty-five colorectal cancers patients were studied for their intratumoural p53 expression using immunohistochemistry (IHC) and ELISA, and circulating p53-Ab. Tumour DNA was analysed for genomic mutations in a subset of 28 patients. Resolts: Seventeen tumours (48,7%) were positive by IHC, and 17 tumour extracts were shown to contain "mutant" conformation p53 proteins (PAb240+), 15 of which were concordant by both methods, p53-Ab were detected in 11 patients (31%). In 10/11 cases, a gene mutation was found in the tumour. All 12 tumours without detectable mutations were IHC and ELISA PAb240-negative. Peridiploid tumors more frequently had wild-type p53 genes and were significantly less frequently IHC- or p53-Ab positive than polyploid tumors. Moreover, 3/4 mutations in exon 8 and 3/3 mutations in exons 5-6 were associated with p53-Ab in contrast with only 3/9 mutations in exon 7. If exon 7 mutations was compared to the rest, the difference was significant (p<0.04). Finally, 2/3 of pts with mutations in codon 273 had p53Ab compared to only 1/4 of those in codon 248. Fourteen of 22 tumours located in the distal colon had mutations in contrast with only 2/6 tumours located in the proximal colon (p<0.001). In a contrast, the site of cancer did not influence the prevalence of p53-Ab (8/27 vs 3/8, ns). Conclusion; a high agreement in the detection of p53 alterations was found in our study. However, our data suggest that all p53 gene mutations may not be equivalent in term of immunogenicity. • G2490 THE SIGNIFICANCE OF DUODENAL POLYPS: A FIVE-YEAR REVIEW OF HISTOLOGICAL FEATURES AND NATURAL HISTORY. R.I.H. Hammett. T.R. Heap, R. Eckstein. Departments of Gastroenterology and Anatomical Pathology. Royal North Shore Hospital. University of Sydney. Australia. Unlike the colon, where an adenoma-carcinoma sequence has been established, no such link has been proven in the duodenum in patients without a familial polyposis syndrome. As a result, management decisions regarding duodenal polyps are currently based on little scientific data. We therefore collected prospective data on all patients presenting for endoscopy with the aim of evaluating the incidence, histological characteristics and natural history of duodenal polyps. Methods: From 1991-1996 data was collected prospectively on over five thousand patients attending our institution for upper gastrointestinal endoscopy. Inflammatory polyps and Brunner's gland hyperplasia in the first part of the duodenum were not included in this analysis as previous studies have shown these lesions to be invariably benign 1, Histological characteristics of the polyps were recorded and dysplasia graded as mild, moderate or severe. Endoscopy reports recorded the site of polyp formation, size of polyp and associated clinical syndromes. The subsequent clinical course of patients identified with polyps was obtained via telephone interviews and written correspondence with the physician caring for the patient and from their medical records.Results; Nineteen patients (12M, mean age 55 years) were identified with duodenal polyps. Familial polyposis syndromes were found in 6/19 (32%). Polyps were most commonly found in the second part of the duodenum (63%) or the periampullary region (16%). Moderate to severe dysplasia was found in 58% of polyps, and mild dysplasia in 42% of polyps. All patients with severe dysplasia, and one patient with moderate dysplasia underwent removal of their polyps; two with endoscopic snare polypectomy, and two surgically. In the remaining 15 patients the polyps were biopsied but not removed. To date no patient has developed adenocarcinoma in the duodenum (mean follow up 37 months, range 10-78 months). Conclusions: There does not appear to be a rapid progression from dysplasia to carcinoma in patients who do not suffer from a familial polyposis syndrome. Peiampullary polyps appear to be more likely to be severely dysplastic and so should be treated with greater caution. Removal of polyps with moderate to severe dysplasia appears to prevent the development of adenocarcinoma at the site of polypectomy. [1] Jepsen JM et al.Scand J Gastroenterology 1994;29:483-487
April 1998 pathway, particularly mevalonate, famesol and geranylgeraniol (GG) in the lovastatin-induced apoptosis. Lovastatin induced changes including apoptosis were completely inhibited by mevalonate 100 laM and GG 1 laM but only partially by farnesol 50 ~tM, suggesting that inhibition of famesylation of ras is not the major mechanism of action of lovastatin and that some other proteins which are geranylgeranylated are the predominant targets. To determine whether the effect of lovastatin were entirely due to inhibition of activity of the various isoprenylated G-proteins, we treated the IEC-18 ceils with lovastatin and cycloheximide. Cycloheximide completely prevented the Iovastatin-induced changes in the IEC-18 cells, showing that new protein synthesis is required not only for apoptosis but also for the lovastatin induced changes in the cell structure and adhesion. To conclude, lovastatin alters cell morphology and induces loss of cell adhesion and p53 dependent (or p53 sensitive) apoptosis in IEC-18 cells independent of ras expression. The effects of lovastatin are predominantly due to inhibition of geranylgeranylation (rather than farnesylation) and require synthesis of certain (presently unidentified) proteins which may mediate these effects. • G2487 METHYLENE BLUE STAINING FOR THE ENDOSCOPIC DIAGNOSIS OF INTESTINAL METAPLASIA IN THE STOMACH. D. Halperin, R. Belmonte, L. Sanchez, A. Mohar, J. Guarner, R. Herrera, Parsonnet. J. San Cristobal de las Casas and Mexico City, Mexico, Atlanta, GA and Stanford, CA. Staining of the gastric mucosa with methylene blue (MB) has been suggested as a useful method for determining presence and extent of intestinal metaplasia (IM) at gastroscopy. We evaluated the sensitivity, specificity and predictive power of MB staining in a population with very high prevalence of gastric cancer and preneoplastic lesions. Methods- Two endoscopists carried out a total of 148 gastroscopies as part of a study on gastric preneoplastic lesions in Chiapas, Mexico. Following application of a solution of acetyl cysteine (Mucomyst ®) to dissolve gastric mucus, methylene blue (0.01% solution) was applied through a spray catheter to the gastric mucosa. The stomach was then washed with approximately 200 ml of water to eliminate non-specific staining of mucus. The endoscopists described the gastric mucosa as: diffuse staining, focal staining and nonstaining. A total of seven biopsies of the gastric mucosa were taken from stained and unstained areas. Biopsies were evaluated by two pathologists blinded to the results of the MB staining using the revised Sydney Classification for gastritis. Results- Diffuse MB staining was noted at endoscopy in 65 subjects, focal staining in 69 subjects and no staining in only 14 subjects. By histology, intestinal metaplasia was identified in 72 (49%) of the 148 patients; 54(36%) had complete IM, 22 (15%) had incomplete IM (4 patients had both types). For all intestinal metaplasia, the sensitivity and specificity of staining were 96.05% and 15.28%, respectively. The predictive power positive and negative were 54.48% and 78.57%. When analyzed by IM type and/or by type of staining (diffuse vs. focal), there was no improvement in test characteristics. Even after gaining considerable experience, the endoscopists found the procedure to be cumbersome and the staining results subjective. Discussion. In a population with high gastric cancer rates, we did not find methylene blue staining at the time of gastroscopy to be a useful diagnostic test for IM due to the high number of false positives and the subjectivity of the procedure. G2488
GERMLINE MUTATION OF THE PTEN GENE IN JAPANESE PATIENTS WITH COWDEN DISEASE. N.Hamano. T.Okada, A.Suzuki, Y.Takeda, H.Mabuchi, 2nd Department of Internal Medicine, Kanazawa University, Ishikawa, Japan. Background and Aim: Cowden disease, also known as multiple hamartoma syndrome, is an autosomal cancer syndrome with a high risk of breast and thyroid cancer. Recently, the tumor suppressor gene PTEN, encoding a putative protein tyrosine or dual specificity phnsphatase and located at chromosome 10q23.3, was reported as the gene causing Cowden disease. In this study, we analyzed germline mutations of the PTEN gene in Japanese patients with Cowden disease. Subjects: Three Japanese patients with Cowden disease and their families. The patients' clinical manifestations are shown below. Patient Sex Age
Mucocutaneous Thyroid Breast Intestine Others Face Oral Skin + + + adenoma cancer osteoma
case 1
M
41
case 2
M
28
+
+
+
case 3
F
48
+
+
+
adenoma gyneco- polyps scoliosis mastia adenoma cancer polyps pulmonary hamartornas
Methods: Genomic DNA was isolated from the whole blood of the patients and their families. Exons of the PTEN gene were amplified by PCR. Sequencing of the exons was performed using non-radioactive method. Results: 1) In case 2, sequencing exon 7 of the PTEN gene revealed a nonsense mutation, CGA to TGA: Arg233Stop. Presence of the same mutation in Western patients with Cowden disease was previously reported,
so we conclude this is pathogenic. Because his parents displayed neither mutation of the PTEN gene nor clinical manifestations of Cowden disease, it would appear to have occured de novo. 2) In case 3, sequencing exon 8 of the PTEN gene revealed a missense mutation, CGA to CTA: Arg335Leu, which we could not identify in normal controls. To our knowledge, this mutation have not been previously reported. Conclusion: Germline mutations in the PTEN gene in Japanese patients with Cowden disease were identified. G2489
CORRELATIONS BETWEEN p53 OVEHEXPRESSION, SERUM ANTIBODIES AND GENE MUTATION IN COLORECTAL CANCER. P. Hammel 1, K. Leroy-Viard 2, M.T. Chaumette 2, J. Villandy 3, M.C. Falzone 2, D. Rouillard 3, Y. Remvikos 3, T. Soussi3. 1Gastroenterology Departement, H6pital Beanjon, 92118 Clichy; 2Pathology Departement, H6pital Henri Mondor, 94010 Cr6teil, 3Institut Curie, 75005 Paris, France. Background: only half of colorectal cancers with p53 gene mutations seem to elicit serum antibodies (p53-Ab) in response to intratumoral p53 protein accumulation. Aim: Our study was designed to compare cellular events (p53 protein expression and gene mutations) to the presence of circulating p53-Ab. Patients and Methods: Thirty-five colorectal cancers patients were studied for their intratumoural p53 expression using immunohistochemistry (IHC) and ELISA, and circulating p53-Ab. Tumour DNA was analysed for genomic mutations in a subset of 28 patients. Resolts: Seventeen tumours (48,7%) were positive by IHC, and 17 tumour extracts were shown to contain "mutant" conformation p53 proteins (PAb240+), 15 of which were concordant by both methods, p53-Ab were detected in 11 patients (31%). In 10/11 cases, a gene mutation was found in the tumour. All 12 tumours without detectable mutations were IHC and ELISA PAb240-negative. Peridiploid tumors more frequently had wild-type p53 genes and were significantly less frequently IHC- or p53-Ab positive than polyploid tumors. Moreover, 3/4 mutations in exon 8 and 3/3 mutations in exons 5-6 were associated with p53-Ab in contrast with only 3/9 mutations in exon 7. If exon 7 mutations was compared to the rest, the difference was significant (p<0.04). Finally, 2/3 of pts with mutations in codon 273 had p53Ab compared to only 1/4 of those in codon 248. Fourteen of 22 tumours located in the distal colon had mutations in contrast with only 2/6 tumours located in the proximal colon (p<0.001). In a contrast, the site of cancer did not influence the prevalence of p53-Ab (8/27 vs 3/8, ns). Conclusion; a high agreement in the detection of p53 alterations was found in our study. However, our data suggest that all p53 gene mutations may not be equivalent in term of immunogenicity. • G2490 THE SIGNIFICANCE OF DUODENAL POLYPS: A FIVE-YEAR REVIEW OF HISTOLOGICAL FEATURES AND NATURAL HISTORY. R.I.H. Hammett. T.R. Heap, R. Eckstein. Departments of Gastroenterology and Anatomical Pathology. Royal North Shore Hospital. University of Sydney. Australia. Unlike the colon, where an adenoma-carcinoma sequence has been established, no such link has been proven in the duodenum in patients without a familial polyposis syndrome. As a result, management decisions regarding duodenal polyps are currently based on little scientific data. We therefore collected prospective data on all patients presenting for endoscopy with the aim of evaluating the incidence, histological characteristics and natural history of duodenal polyps. Methods: From 1991-1996 data was collected prospectively on over five thousand patients attending our institution for upper gastrointestinal endoscopy. Inflammatory polyps and Brunner's gland hyperplasia in the first part of the duodenum were not included in this analysis as previous studies have shown these lesions to be invariably benign 1, Histological characteristics of the polyps were recorded and dysplasia graded as mild, moderate or severe. Endoscopy reports recorded the site of polyp formation, size of polyp and associated clinical syndromes. The subsequent clinical course of patients identified with polyps was obtained via telephone interviews and written correspondence with the physician caring for the patient and from their medical records.Results; Nineteen patients (12M, mean age 55 years) were identified with duodenal polyps. Familial polyposis syndromes were found in 6/19 (32%). Polyps were most commonly found in the second part of the duodenum (63%) or the periampullary region (16%). Moderate to severe dysplasia was found in 58% of polyps, and mild dysplasia in 42% of polyps. All patients with severe dysplasia, and one patient with moderate dysplasia underwent removal of their polyps; two with endoscopic snare polypectomy, and two surgically. In the remaining 15 patients the polyps were biopsied but not removed. To date no patient has developed adenocarcinoma in the duodenum (mean follow up 37 months, range 10-78 months). Conclusions: There does not appear to be a rapid progression from dysplasia to carcinoma in patients who do not suffer from a familial polyposis syndrome. Peiampullary polyps appear to be more likely to be severely dysplastic and so should be treated with greater caution. Removal of polyps with moderate to severe dysplasia appears to prevent the development of adenocarcinoma at the site of polypectomy. [1] Jepsen JM et al.Scand J Gastroenterology 1994;29:483-487