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Query: UMLS:C0009402 (colorectal cancer)
 53,228 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

FAP, if left untreated, results in colorectal cancer. Appropriate early surgical intervention is of utmost importance. With the reduction in mortality from colorectal carcinoma, an increasing number of patients with FAP need lifelong follow-up to screen for extracolonic manifestations. Today, the major causes of death in patients with FAP who are cured of colorectal cancer, or have had a colectomy before its development, are desmoid tumors and periampullary carcinomas. In family members at risk, screening with flexible sigmoidoscopy should be initiated in adolescence; symptoms of diarrhea and rectal bleeding would warrant an even earlier examination. The upper gastrointestinal tract should be assessed endoscopically at the time the diagnosis of FAP is made. If any polyps are detected, a biopsy is essential. If no gastric or duodenal polyps are found, repeated examinations at 3-5 year intervals probably suffice in asymptomatic patients. Surgically, colectomy will be necessary. It is usually deferred until late adolescence, when it is thought that the patient will be mature enough to handle the emotional aspects of the operation as well as the possible future morbidity due to the procedure. The presence or absence of rectal polyps as well as the site and depth of any invasive rectal carcinoma will determine the appropriate surgical procedure. Alternatives must be well understood by the physician and discussed carefully with the patient preoperatively.
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PMID:Familial adenomatous polyposis: case report and review of extracolonic manifestations. 131 Mar 47

Retinoblastoma (RB) and the familial adenomatous polyposis/colorectal cancer (FAP/CRC) complex provide well-characterised examples of multistage carcinogenesis and inheritance of a predisposition to cancer. Retinoblastoma appears to conform to the simple two-step model first proposed by Knudson. The gene responsible for RB, now called Rb1, has been located in chromosome region 13q14. The Rb1 gene has been cloned and subjected to extensive analysis. It is probable that the Rb1 gene product has a role in the regulation of transcription. The familial form of RB occurs as the result of a germline mutation of one of the copies of the Rb1 gene. Colorectal cancer, in contrast, appears to be the result of four or five steps involving both activation of oncogenes and inactivation of antioncogenes. The FAP gene has been located in chromosome region 5q21 by genetic linkage, and a candidate gene, MCC (mutated in colon cancer), has been cloned. Other mutations in previously-identified genes that have been identified as important in the genesis of CRC include the activation of p53 and of Ki-ras. A gene lying in chromosome region 18q which is deleted in colorectal cancer, and hence named DCC has been cloned. Its protein product has sequence homology to neural cell adhesion molecules and other related cell-surface glycoproteins. Delineation of the genes involved in the development of tumours such as RB and CRC provides insight into the mechanisms by which sequential mutations result in carcinogenesis.
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PMID:Multistage carcinogenesis in paediatric and adult cancers. 131 30

The gene for familial adenomatous polyposis coli (APC or FAP), which has previously been linked to chromosome 5q21 has been identified. The APC gene has been found to be altered by point mutations in the germ line of both adenomatous polyposis coli and Gardner's syndrome patients and somatically in tumors from sporadic colorectal cancer patients. During the hunt for the APC gene, the closely linked MCC (mutated in colorectal cancer) gene was identified and found to be altered somatically in tumors from sporadic cancer patients. These data suggest that more than one gene on chromosome 5q21 may contribute to colorectal carcinogenesis and that mutations at the APC gene can cause both adenomatous polyposis coli and Gardner's syndrome. The identification of these genes should aid in the counseling of patients with genetic predispositions to colorectal cancer. Progress has also been made in identifying specific genetic changes that occur in other gastrointestinal cancers. A mutational "hotspot" in the p53 gene in human hepatocellular carcinomas has been identified that could reflect exposure to a specific carcinogen, one candidate being aflatoxin B1.
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PMID:Cell and molecular biology of gastrointestinal tract cancer. 132 39

The Singapore Polyposis Registry was established in 1989 in Singapore General Hospital. The aim is to provide a central registry service to all doctors in Singapore to facilitate in identification, surveillance and management of families and individuals at high risk of getting colorectal cancer from FAP (Familial Adenomatous Polyposis) and HNPCC (Hereditary Non-polyposis Colorectal Cancer). Both have an autosomal dominant inheritance that gives rise to colorectal cancer at any early age if untreated. They account for 5-6% of all colorectal cancers. Sixteen FAP families with 139 members have been evaluated. Fifty-eight members are affected and 81 are at risk or unaffected. Those who have been screened positive have a much lower risk of cancer (13%) compared with those who presented with the disease (89%) and death from colorectal cancer in the corresponding groups were nil and 58%. Eight HNPCC families with 36 affected and 170 at-risk members have been registered. Colonoscopic surveillance have just started: one case of Dukes' A cancer in a 26 year-old patient, and two cases with polyps have been diagnosed. Advances in molecular genetics and the identification of APC (Adenomatous Polyposis Coli) gene in the FAP locus of Chromosome 5 have made it possible to diagnose FAP genetically. This has important impact on management in terms of prenatal diagnosis and dietary and chemoprevention programmes in addition to surgical intervention.
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PMID:The Singapore Polyposis Registry. 132 51

Colo-rectal cancer in young patients is a subject of interest for many reasons. Various studies are devoted to this subject but controversies regarding the stages, the evolution and the prognosis still remains. We present intermediate results, of an ongoing study, which is directed to those particular aspects of colon cancer of the patients less than 45 years of age in a region where the global incidence of the disease is one of the highest in the world. In the past five years, we have observed 602 patients with colon cancer. 23 of them (4%) were less than 45 years old. The age at diagnosis was 38 +/- 6 years. Two-thirds of the subjects were male. 13% had had predisposing conditions for colon cancer such as FAP, ulcerative colitis or Turcot syndrome; 50% had a positive familial history for cancer. Symptoms lasted for less than 3 months in two thirds of the patients. 15% had a right sided tumor, 38% were located in the sigmoid and 28.5% in the rectum. At diagnosis, the tumors were classified as follows: 32% Dukes B, 23% Dukes C and 40% were disseminated disease. Most of them were located in the rectum, but 43% of Dukes B lesions were located in ascending or transverse colon. Grading reveal moderately to poorly differentiated tumors in 3/4 of cases. 30% of patients received an adjuvant therapy. After two years, 70% of the patients were alive. None of them with Dukes A or B but one of the patients with Dukes C were dead.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Colorectal cancer before 45 years of age]. 164 6

The objective of the present study was to determine whether aberrant crypt foci (ACF) similar to those observed in the colons of experimental animals exposed to colon carcinogens could be identified and quantified in the human colon. Twenty-seven colon resections from patients affected by familial adenomatous polyposis (FAP, five cases), colorectal cancer (CRC, 12 cases), and benign diseases of the large bowel (BD, 10 cases) were collected from a pathology repository or immediately after operation. Ten or more 1-cm2 formalin-fixed, methylene-blue--stained samples of colonic mucosa from each colon were scored under light microscopy for ACF. The number of ACF per cm2 and the number of crypts per ACF for each colon were calculated. The average number of ACF per cm2 in the FAP group (20 +/- 19, mean +/- SD) was significantly higher (P less than 0.01) than those of the CRC (0.37 +/- 0.41) and BD (0.18 +/- 0.35) groups. At least one ACF was found in every colon resection from CRC patients and in six out of 10 colon resections from the BD group. The average number of crypts per ACF ranged from five to 35 with absolute values from 1 to over 100. Fifty-five histologic specimens, 43 with ACF of various size and 12 without, were prepared by sectioning the colon parallel to the mucosal surface. There was a close correlation between the number of crypts per ACF in each specimen as scored by methylene-blue and histologic examination. Twenty-six aberrant crypt foci displayed dysplasia as evident by histologic analysis. In these instances we feel the term microadenoma is appropriate and, using this unique approach of examining the human colon, they can be easily identified and quantified. These lesions may well be precursors for adenomatous polyps and colorectal cancer.
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PMID:Identification and quantification of aberrant crypt foci and microadenomas in the human colon. 170 8

There are 3 surgical options for patients who have familial adenomatous polyposis. None of them guarantees a 100% cure of the disease, although they all minimize or eliminate the risk of colorectal cancer. Proctocolectomy with ileostomy is rarely necessary as a procedure of choice. Its only indication would be in patients who have already developed a rectal cancer in the lower third of the rectum. It tends not to be well accepted in asymptomatic patients and acts as a deterrent to family members to even seek help through surveillance. Colectomy with ileorectal anastomosis is a comparatively safe, simple, and uncomplicated procedure with a rapid recovery and a good functional result. It does, however, leave the patient liable for a small risk of rectal cancer, although not a large risk of dying of rectal cancer. Patients who do not do well with ileorectal anastomosis or who subsequently develop large numbers of polyps or even cancer in the upper parts of the rectum at an early stage can still be converted to the third option, which is an ileoanal pouch procedure. Colectomy with rectal mucosectomy and ileoanal pouch procedure with a temporary ileostomy is not, in our view, necessary for all patients with FAP. It is reserved in our practice for patients who present late with large numbers of rectal polyps or for those who desire not to have any risk of rectal cancer and is also used for patients who have had ileorectal anastomosis who develop large numbers of polyps in follow-up surveillance and screening.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Choice of operation in familial adenomatous polyposis. 184 73

Molecular genetic studies of tumor-specific allele loss, originally associated primarily with research regarding childhood hereditary cancers such as retinoblastoma and Wilms' tumors, only lately have been recognized as a relatively fast and fruitful way of locating cancer genes on human chromosomes. To date, over 25 different cancers have been tied to a gene (or genes) on a specific chromosome when this method has been used. During the past year alone, this approach has permitted detection of three genes involved in either hereditary or sporadic colorectal cancers. These three genes, located on chromosomes 5q, 17p, and 18q, are believed to belong to the newly described tumor suppressor (or growth suppressor) gene class, whose effects are opposite those of activated cellular oncogenes, which promote uncontrolled cell growth. Present studies, however, have not shown losses of any of these tumor suppressor genes to be correlated with the presence of activated ras genes in colorectal adenomas or carcinomas. During progression from adenoma to carcinoma, ras gene mutations and 5q allelic deletions are likely to be earlier events, whereas allelic losses from chromosomes 18q and 17p seem to occur more often in advanced tumors. Involvement of the genes on 5q (FAP) and 18q (Lynch syndrome II) in hereditary colon cancer syndromes is supported by linkage studies, but their respective roles (as well as that of the gene on 17p) in familial and sporadic colorectal cancer remain to be precisely defined. Probable isolation of these three genes by molecular cloning within the next few years will help elucidate their specific biologic functions. It will also permit early detection, and thus prevention, of some familial colon cancers (such as FAP), and possibly allow DNA marker-based separation of different colon cancer subtypes of similar histologic appearance.
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PMID:Molecular genetic studies of colon cancer. 264 66

Familial adenomatous polyposis is rare disease, but it is considered as the most important clinical model for studying cancer control and carcinogenesis in general, by its extremely high risk for colorectal cancer as well as for malignancies of diverse organs which is transmitted by autosomal dominant mode. According to Knudson, the mutation for a dominantly inherited cancer susceptibility may be the first step in a recessive change in the tumor cell and same gene may be involved in both familial and non-familial cases of the tumor. The recent studies by Bodmer et al and by Solomon et al which reported on FAP locus in chromosome 5 and on loss of heterozygosity of this locus in the colorectal cancer have made an important break through in proving the Knudson's hypothesis. The epidemiological, clinical and pathological observations on FAP including our studies has been discussed in the view of these recent development of molecular biology.
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PMID:[Recent trends in studies on carcinogenesis in familial adenomatous polyposis]. 282 45

Colorectal cancer is the second most common cancer in the United Kingdom and other developed countries in the West. Although it is usually not familial, there is a rare dominantly inherited susceptibility to colon cancer, familial adenomatous polyposis (FAP; also often previously called familial polyposis coli). During adolescence affected individuals develop from a few hundred to over a thousand adenomatous polyps in their large bowel. These are sufficiently likely to give rise to adenocarcinomas to make prophylactic removal of the colon usual in diagnosed FAP individuals. Adenomas may occur elsewhere in the gastrointestinal tract and the condition is often associated with other extracolonic lesions, such as epidermoid cysts, jaw osteomata and fibrous desmoid tumours. Adenomata have been suggested to be precancerous states for most colorectal tumours. Knudson has suggested that the mutation for a dominantly inherited cancer susceptibility may be the first step in a recessive change in the tumour cells, and that the same gene may be involved in both familial and non-familial cases of a given tumour. Following up a case report of an interstitial deletion of chromosome 5 in a mentally retarded individual with multiple developmental abnormalities and FAP, we have now shown that the FAP gene is on chromosome 5, most probably near bands 5q21-q22.
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PMID:Localization of the gene for familial adenomatous polyposis on chromosome 5. 303 73


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