The effect of sulindac on colon polyps: Circumvention of a transformed phenotype—A hypothesis

Sulindac suppresses the growth of colon polyps in Gardner syndrome and familial adenomatous polyposis. The mechanism of action is not known. The problems are to ascertain the significance of high prostaglandin concentrations in transformed cells, colon polyps and cancers and to explain how sulindac restores normal growth patterns. A few clinical observations and an abundance of experimental data can be integrated to produce a reasonable model based on current biochemical and physiologic concepts. A fundamental defect in the formation of colon polyps is mutation of the APC (adenomatous polyposis coli) gene that leads to inadequate suppression of proliferation. There is high PGE₂ content in colon polyps and cancers, presumably the result of stimulation by protein kinase C (PKC). In small quantities it stimulates cyclic AMP production but with persistent high concentrations it desensitizes and down-regulates specific PG receptors and inactivates adenylate cyclase, cAMP synthesis, and the cAMP-dependent mechanism for control of proliferation. The PKC pathway is thereby unopposed. It is hypothesized that restriction of PG synthesis by sulindac is accompanied by resensitization of PG receptors, and reactivation of the cAMP-dependent pathway for control of cell growth. It is further postulated that restoration of cAMP synthesis and protein kinase A activity converts a functionally inadequate mutant APC suppressor gene to one sufficient to inhibit colon polyp formation. © Wiley-Liss, Inc.     

Torre's syndrome in association with premalignant and malignant tumors and suspected familial polyposis

Torre's syndrome was diagnosed in a patient with the clinical characteristics of familial polyposis coli, an association, that to our knowledge, has not been reported previously.     

CXCR2 inhibition enhances sulindac‐mediated suppression of colon cancer development

Small chemical compound sulindac has been approved as a preventive approach against colon cancer for its effectiveness in treatment of precancerous adenoma. Due to its severe toxicities in the cardiovascular, gastrointestinal and renal systems, however, a combination of low‐dose sulindac with other chemopreventive agents has been sought after as an alternative therapeutic strategy that could increase its effectiveness, while minimizing its adverse effects. To identify the promising alternative approach, we investigated the therapeutic potential of targeting the interleukin (IL)?8/CXCR2 pathway in colon cancer treatment using both loss‐of‐function (CXCR2 knockout) and gain‐of‐function (IL‐8 overexpression) mouse models, as the IL‐8/CXCR2 pathway has been shown to be activated in intestinal tumors of both human and experimental animals. We found that deletion of CXCR2 gene and ectopic expression of IL‐8 suppresses and enhances, respectively, intestinal tumor development caused by a mutation in the APC gene. Moreover, a single copy deletion of CXCR2 gene resulted in abrogation of COX‐2 and Gro‐α upregulation in intestinal tumors caused by the APC mutation. Moreover, a single copy (heterozygote) deletion of CXCR2 gene was sufficient to synergize with a low‐dose sulindac treatment in suppressing APCmin‐induced intestinal polyposis. Together, our study provides a therapeutic justification of combined inhibition of CXCR2 and sulindac treatment in colon cancer prevention.     

Multiple lymphomatous polyposis

Multiple lymphomatous polyposis (MLP) is a distinctive and particularly rare clinical type of malignant gastrointestinal lymphoma, which is classified as B-cell centrocytic non-Hodgkin's lymphoma. This rare entity has been recently reclassified as mantle cell lymphoma. We herein report three additional cases of MLP involving various segments of the gastrointestinal tract. MLP has an aggressive biologic behavior and a relatively poor prognosis and must be treated accordingly as a high-grade lymphoma with systemic chemotherapy. J. Surg. Oncol. 64:336–340, 1997. © 1997 Wiley-Liss, Inc.     

Impact of adenomatous polyposis coli (APC) tumor supressor gene in human colon cancer cell lines on cell cycle arrest by apigenin

This research assessed the importance of the adenomatous polyposis coli (APC) tumor suppressor mutation in the ability of apigenin to induce cell cycle arrest using HT29-APC cells, which contain inducible wild-type APC under the metallothionein promoter. HT29-GAL cells, containing beta-galactosidase (GAL), were included as control. Treatment with apigenin (0, 20, 40, 60, and 80 microM) for 48 h resulted in reduction in the cell number (P < 0.05) concurrent with flow cytometry results showing a dose-dependent accumulation of cells in the G2/M phase in both HT29-APC and HT29-GAL cells without ZnCl(2) treatment. Flow cytometric analysis showed an increase (P < 0.05) in the percentage of cells in G2/M when HT29-APC cells were treated with 80 microM apigenin for 120 h. This increase was not present in HT29-APC cells when treated with both 80 microM apigenin and 100 microM ZnCl(2) for 120 h. Western blot analysis verified the induction of APC protein expression in ZnCl(2)-treated HT29-APC cells but not in ZnCl(2)-treated HT29-GAL cells. Apigenin plus ZnCl(2) treatment increased the expression of APC protein in HT29-APC cells by 50 fold above expression observed with ZnCl(2) alone. Upon induction of the APC gene with ZnCl(2) in HT29-APC cells, the percentage of apoptotic cells increased significantly (P < 0.05) after 120-h treatment. Additionally, apigenin treatment (80 microM) further increased the percentage of apopototic HT29-APC following ZnCl(2) treatment to induce wild-type APC expression. These results suggest that APC dysfunction may be critical for apigenin to induce cell cycle arrest in human colon cancer cell lines and furthermore, apigenin enhances APC expression and apoptosis in cells with wild-type APC.     

Hamartomatous polyposis syndromes

Hamartomas are tumour-like malformations, consisting of disorganized normal tissues, typical of the site of tumour manifestation. Familial manifestation of hamartomatous polyps can be noted in juvenile polyposis syndrome (JPS), Peutz-Jeghers’ syndrome (PJS), hereditary mixed polyposis syndrome (HMPS) and PTEN hamartoma tumour syndrome (PHTS). All the aforementioned syndromes are inherited in an autosomal dominant manner and form a rather heterogenous group both in respect to the number and localization of polyps and the risk of cancer development in the alimentary tract and other organs. Individual syndromes of hamartomatous polyposis frequently manifest similar symptoms, particularly during the early stage of the diseases when in several cases their clinical pictures do not allow for differential diagnosis. The correct diagnosis of the disease using molecular methods allows treatment to be implemented earlier and therefore more effectively since it is followed by a strict monitoring of organs that manifest a predisposition for neoplastic transformation.     

Nonfamilial Turcot's syndrome associated with Turner's syndrome, multiple carcinomas of the tongue, and cancer of the colon

Herein we present the clinical and cytogenetic data of a patient with Turner's and Turcot's syndrome associated with multiple carcinomas of the tongue and cancer of the colon.     

Total gastrectomy with isoperistaltic jejunal interposition flap for symptomatic management of gastric polyposis from familial adenomatous polyposis

Patients with familial adenomatous polyposis (FAP) oftentimes have extracolonic polyps. The patient discussed in this case report had innumerable gastric polyps which were significantly affecting his ability to tolerate oral intake and his overall nutrition. Medical management was not sufficiently controlling his symptoms; therefore we proceeded with surgical intervention. We discuss the use of a total gastrectomy with an Isoperistaltic jejunal interposition flap for the symptomatic management of gastric polyposis. We describe the technique used and benefits to this specific procedure when it comes to long term outcome, complications, and monitoring.     

A comparison of the phenotype and genotype in adenomatous polyposis patients with and without a family history

Objectives: Adenomatous polyposis of the colon is often secondary to an inherited mutation in adenomatous polyposis coli (APC) gene, however, approximately one third of patients have no family history of the disease. We studied the phenotype and genotype of adenomatous polyposis in patients without a family history. Methods: A cohort of 57 unrelated adenomatous polyposis patients were evaluated. Seventeen patients with no family history were compared with 40 patients who had a positive family history of the disease. Family history and medical records were collected and analyzed. Germline APC and Mut Y homologue (MYH) testing was undertaken. Results: Patients without a family history were diagnosed with polyposis at an older age (41 years vs. 32 years) and presenting more frequently with symptoms (76 vs 20, P < 0.05). The number of colonic polyps and frequency of extracolonic manifestation associated with adenomatous polyposis did not differ between the two groups. APC mutations were detected less frequently among patients without a family history of the disease (4 out of 17 vs 25 out of 40, P=0.007), even among those with greater than 100 colorectal adenomas (4 out of 12 versus 21 out of 29, P=0.03). One homozygous MYH mutation carrier (G382D) was detected among the six patients without a family history and without a germline APC mutation who were tested. Conclusions: Adenomatous polyposis patients without a family history are usually diagnosed with symptoms, and at a later age. Phenotypically, they are similar to those with a family history. However, germline APC mutations are detected far less frequently in patients without a family history. A small percentage of these cases may be secondary to biallelic germline MYH mutations.     

Genotype and phenotype of patients with both familial adenomatous polyposis and thyroid carcinoma

The incidence of thyroid carcinoma in familial adenomatous polyposis (FAP) is thought to be 1%–2%, with the majority of cases being female. We have investigated the phenotype and genotype of 16 patients with FAP associated thyroid carcinoma. Among 1194 FAP patients studied in two high risk registries in North America (Familial Gastrointestinal Cancer Registry, Toronto and University California, San Francisco), 16 (1.3%) unrelated patients with FAP associated thyroid cancers were identified. Adenomatous polyposis coli (APC) gene testing was performed in 14 of the 16 cases. The average age of diagnosis for FAP and thyroid carcinoma was 29 years (range 17–52 years) and 33 years (range 17–55 years), respectively. All FAP patients except 1 had more than 100 colonic adenomas. Extracolonic manifestations, beside thyroid cancer, were presented in 81% (n = 13) of the patients, including gastric and duodenal polyps, desmoid tumor, osteoma, epidermoid cyst, sebaceous cyst and lipoma. Colorectal cancer was diagnosed in 38% (n = 6) of the patients. The pathology of the FAP associated thyroid cancer was predominantly papillary carcinoma. Germline mutations were identified in 12 of 14 patients tested. Mutations proximal to the mutation cluster region (1286–1513) were detected in 9 cases. Thyroid cancer in our FAP population was rare, predominantly in females and showed papillary carcinoma histology. Additionally, thyroid cancer in our patients occurred in the setting of classic FAP phenotype. Germline mutations were located predominantly outside the APC mutation cluster region. This revised version was published online in August 2006 with corrections to the Cover Date.     

Resorting the function of the colorectal cancer gatekeeper adenomatous polyposis coli

As a large number of cancers are caused by nonsense mutations in key genes, read-through of these mutations to restore full-length protein expression is a potential therapeutic strategy. Mutations in the adenomatous polyposis coli (APC) gene initiate the majority of both sporadic and hereditary colorectal cancers (CRC) and around 30% of these mutations are nonsense mutations. Our goal was to test the feasibility and effectiveness of APC nonsense mutation read-through as a potential chemo-preventive therapy in Familial Adenomatous Polyposis (FAP), an inherited CRC syndrome patients. Ten FAP patients harboring APC nonsense mutations were treated with the read-through inducing antibiotic erythromycin for 4 months. Endoscopic assessment of the adenomas was performed at baseline, after 4 and after 12 months. Adenoma burden was documented in terms of adenoma number, maximal polyp size and cumulative polyp size per procedure. Tissue samples were collected and subjected to molecular and genetic analyses. Our results show that in the majority of patients the treatment led to a decrease in cumulative adenoma burden, median reduction in cumulative adenoma size and median reduction in adenoma number. Molecular and genetic analyses of the adenomas revealed that the treatment led to a reduced number of somatic APC mutations, reduced cellular proliferation and restoration of APC tumor-suppressing activity. Together, our findings show that induced read-through of APC nonsense mutations leads to promising clinical results and should be further investigated to establish its therapeutic potential in FAP and sporadic CRCs harboring nonsense APC mutations.     

Chemoprevention of colon cancer by dietary fatty acids

During the last two decades, substantial progress has been made in the understanding of the relationship between the dietary constituents and development of colon cancer in man. Unlike studies of cancer among smokers and nonsmokers, nutritional epidemiologic studies are confronted with the inherent difficulty of assessing reasonably precise exposures. The lack of consistency between international correlation studies and case-control studies does not necessarily negate a dietary etiology of colon cancer because these inconsistencies may have arisen, at least in part, from methodological limitations. Some of these deficiencies in epidemiological studies of diet and cancer have been corrected; recent case-control studies demonstrated that high dietary fat is a risk factor for colon cancer development and that an overall increase in intake of foods high in fiber might decrease the risk for colon cancer. The results of epidemiologic studies may be assumed to present conservative estimates of the true risk for cancer associated with diet. The populations with high incidence of colon cancer are characterized by high consumption of dietary fat, which may be a risk factor in the absence of factors that are protective, such as whole-grain cereals and of other high-fiber. Laboratory animal model studies have shown that certain dietary lipids and fibers influence tumorigenesis in the colon. The data of metabolic epidemiological and laboratory animal model studies are sufficiently convincing with recpect to enhancement of colon cancer by type of fat and protection by certain dietary fibers.     

A clinical overview of familial adenomatous polyposis derived from the database of the Polyposis Registry of Japan

The clinical situation of familial adenomatous polyposis (FAP) in Japan has changed in the period since the last analysis of data of the Japanese Polyposis Center. To reevaluate our data and elucidate the changes we analyzed the records of the 1390 FAP patients in 900 families registered with the Polyposis Committee of the Japanese Society for Cancer of the Colon and Rectum. In the 13-year period 1990–2003, clinical differences between men and women with FAP diminished. The postoperative prognosis was substantially better in patients without advanced colorectal cancer (stage T2) than in those with early cancer or no cancer. Mean age at death improved from 42.5 years in the period before 1990 to 46.0 years, and it was a result of a decreased proportion of deaths from colorectal cancer. The distribution of colorectal cancer in FAP patients was similar to that in the general population. Desmoid tumors accounted for about 10% of deaths in the recent 13 years (1990–2003). The cumulative risk of rectal cancer in the preserved rectum was 12% at 10 years and 23% at 15 years. The registry system in Japan revealed a new clinical situation in FAP patients, and the findings of this study will be useful to improve the prognosis of patients with FAP.     

Evidence for an hMSH3 defect in familial hamartomatous polyps

BACKGROUND:

Patients with hamartomatous polyposis syndromes have increased risk for colorectal cancer (CRC). Although progression of polyps to carcinoma is observed, pathogenic mechanisms remain unknown. The authors examined whether familial hamartomatous polyps harbor defects in DNA mismatch repair (MMR), and assayed for somatic mutation of PTEN, a gene inactivated in the germline of some hamartomatous polyposis syndrome patients.

METHODS:

Ten hamartomatous polyposis syndrome patients were genotyped for germline mutations. Epithelial and nonepithelial polyp DNA were assayed for microsatellite instability (MSI) and PTEN frameshift mutation. DNA MMR and PTEN protein expression were assessed in all polyps by immunohistochemistry. In addition, 99 MSI‐high sporadic CRCs and 50 each of hMLH1^?/? and hMSH3^?/? cell clones were examined for PTEN frameshifts.

RESULTS:

Twenty‐five (58%) of 43 hamartomatous polyposis syndrome polyps demonstrated dinucleotide or greater MSI in polyp epithelium, consistent with hMSH3 deficiency. MSI domains lost hMSH3 expression, and PTEN expression was lost in polyps from germline PTEN patients; sporadic hamartomatous polyps did not show any of these findings. PTEN analysis revealed wild type exon 7 and 8 sequences suggestive of nonexistent or rare events for PTEN frameshifts; however, MSI‐high sporadic CRC showed 11 (11%) of 99 frameshifts within PTEN, with 4 tumors having complete loss of PTEN expression. Subcloning hMLH1^?/? and hMSH3^?/? cells revealed somatic PTEN frameshifts in 4% and 12% of clones, respectively.

CONCLUSIONS:

Nondysplastic epithelium from hamartomatous polyposis syndrome polyps harbors hMSH3 defects, which may prime neoplastic transformation. Polyps from PTEN^+/? patients lose PTEN expression, but loss is not a universal early feature of all hamartomatous polyposis syndrome. However, PTEN frameshifts can occur in hMSH3‐deficient cells, suggesting that hMSH3 deficiency could drive hamartomatous polyposis syndrome tumorigenesis. Cancer 2011. © 2010 American Cancer Society.     

Les tumeurs desmoïdes en pédiatrie : état des connaissances actuelles

Desmoid tumor (DT) or aggressive fibromatosis is a histologically benign-appearing neoplasms of the soft tissues, arising from connective tissues, the fascial sheaths and musculoaponevrotic structures of muscles. DT is a non-metastasizing tumor but has a potential for local invasion and local recurrence. DT can be seen in all age groups including young children. The overall incidence is reported as 2-4 cases per million per year. The etiology of DT is unknown. However, a genetic predisposition, familial adenomatous polyposis and Gardner's syndrome, has been implicated in 2% of the cases. The histological diagnosis has to be confirmed by biopsy in order to eliminate other sarcomas. The clinical behavior of DT seems unpredictable with a high rate of local recurrence. Treatment depends on the aggressiveness of the disease. A “wait-and-see” strategy is, at the present time, preferred in case of asymptomatic or non-progressive disease. Complete resection after surgery is rare, that is why first-line surgery should be seriously questioned and only considered when a complete resection can be feasible without functional or cosmetic damage. If not, medical treatments (cytotoxic or not) are rather discussed. Radiation therapy is rarely an option in children in this benign tumor. Authors present accurate knowledge of this disease in children.     

Familial adenomatous polyposis of the colon

Familial adenomatous polyposis (FAP) is a well-defined autosomal dominant predisposition to the development of polyposis in the colon and rectum at unusually early ages. The first symptoms of FAP are diarrhea and blood in the stool. Weight loss and weaknesses occur after the development of advanced tumour. The incidence of the FAP disorder is one per 10000 newborns. There are high levels of heterogeneity with regard to the number and timing of the occurrence of polyps. The classical form of FAP is characterized by the presence of more than 100 polyps, which appear in the second decade of life. The average time of occurrence of polyps is 15 years. The earliest symptoms of polyposis have been observed in a three-year-old child. The polyps are characterized by large potential for the development towards malignant tumour. Malignancy can occur from late childhood onwards. Attenuated adenomatous polyposis coli is characterized by a more benign course of disease in contrast to classical FAP. The occurrence of FAP is associated with mutations in the APC tumour suppressor gene, which was described in 1991. The APC gene is located on chromosome 5q21 and is involved in cell proliferation control. A recessive form of adenomatous polyposis is caused by mutations in the base excision repair gene - MUTYH gene. The MUTYH gene is involved in repairing DNA lesions as a result of oxidative DNA damage. MUTYH associated polyposis (MAP) is a predisposition to the development of polyps of the colon but the number of polyps is lower in comparison to classical FAP. The high risks of cancer observed in these two diseases make them important medical issues. Molecular studies of colonic polyposis have been performed in Poland for over fifteen years. A DNA Bank for Polish FAP patients was established at the Institute of Human Genetics in Poznan in which DNA samples from 600 FAP families have been collected.     

Balance between endoscopic and genetic information in the choice of ileorectal anastomosis for familial adenomatous polyposis

BACKGROUND AND OBJECTIVES: The number of rectal polyps and the site of mutations in the APC (Adenomatous polyposis coli) gene have been used to guide the surgical management in patients with familial adenomatous polyposis (FAP). The aim of this study is to assess the utility of the APC mutation screening compared to the degree of the rectal polyposis in surgical decision making. METHODS: The post-surgical courses of 25 patients submitted to subtotal colectomy with ileorectal anastomosis (IRA) were reviewed. Preservation of the rectum was prospectively decided on the basis of well-defined endoscopic criteria. The number of rectal polyps was assessed preoperatively and every 6-12 months. APC gene was screened for mutations by heteroduplex analysis, single strand conformation polymorphism, in vitro synthesized protein (IVSP), and DNA sequencing. Patients negative for APC mutations were tested for MYH mutations. RESULTS: On the basis of preoperative polyp rectal count we categorized patients as follows: Group I, 5 or fewer adenomas; Group II, 6-9 adenomas; Group III, 10 or more adenomas. After a follow-up ranging from 12 to 225 months we have observed a significant difference of recurrent rectal adenomas between Groups I-II versus III. No difference was detected among patients of Group I and II. The mean number of adenomas/year/patient was 0.67, 1.62, and 9.29 for Group I, II, and III, respectively. Carpeting polyposis of the rectal stump developed in three patients with APC mutation at codon 1309 and two of them needed later proctectomy. Diffuse rectal polyposis was observed in one patient with mutation at exon 9 who had 10 small polyps at time of surgery. Mutation at the 5'-end of APC (codons 144-232), mutation of MYH and unknown APC or MYH mutation were correlated with a low number of polyps both at presentation and follow-up. No IRA patients developed rectal cancer. CONCLUSIONS: In our experience fewer than 10 rectal polyps at presentation can predict a favorable outcome after IRA. Identification of specific germ-line APC or MYH mutation can address the choice of surgical treatment.