Investigations on the significance of the adenoma-carcinoma sequence in the small bowel

The role of defective mismatch repair in small bowel adenocarcinoma in celiac disease

Celiac disease is associated with an increased risk of small bowel adenocarcinoma. The aims of this study were to investigate the molecular basis, assess outcomes, and identify clinicopathologic characteristics of small bowel adenocarcinoma in celiac disease. Retrospective case control cohort study of all celiac disease patients treated at our institution for small bowel adenocarcinoma and matched control patients with sporadic small bowel adenocarcinoma from July 1960 to November 2002. Mismatch repair (MMR) status was accessed by testing tissue for microsatellite instability (MSI) and for hMLH1 and hMSH2 protein expression. Over a 40-year time period, 18 patients with small bowel adenocarcinoma and celiac disease were treated at the Mayo Clinic. One celiac disease patient was excluded. High-frequency MSI (MSI-H) was identified in 8 of 11 (73%) and 2 of 22 (9%) available small bowel adenocarcinoma specimens in the celiac disease and control groups, respectively. In the celiac disease group, MSI-H was associated with loss of hMLH1 and hMSH2 in 6 and 1 specimens, respectively. Loss of hMLH1 occurred in both control tumors. Stage was associated with celiac disease status (P = 0.018), and 78% of controls were stage III or IV compared with 47% of celiac disease patients. Overall, survival was better (P = 0.025) in the celiac disease group compared with stage-matched controls. Celiac disease patients with small bowel adenocarcinoma had a high incidence defective MMR (73%) compared with controls and had better survival compared with stage-matched controls. In addition, celiac disease patients presented more frequently with early-stage small bowel adenocarcinoma. The better survival and earlier presentation of small bowel adenocarcinoma in celiac disease appears to be biologically associated with defective MMR.

Small Bowel Adenocarcinoma: A Rare but Aggressive Disease

Unlike the colon and rectum, the small intestine is associated with a very low rate of tumor occurrence. Adenocarcinomas represent the most frequent of these rare digestive tumors and are often fatal as a result of tardy diagnosis. Regardless of the stage, surgery usually remains the cornerstone of small bowel adenocarcinoma therapy. Because of the rarity of the disease, very few significant clinical trials have identified any efficient nonsurgical treatment; however, recent data indicate these tumors might be sensitive to chemotherapy alone or in association with radiation therapy. Conversely, a great deal of progress has been achieved in diagnosis of the tumor, whether by adaptation of existing techniques or development of new ones. We reviewed the clinical aspects of this rare but aggressive disease, focusing on new diagnostic procedures as well as on recent advances in their therapeutic management.

Alteration of Cytokeratin 7 and Cytokeratin 20 Expression Profile Is Uniquely Associated With Tumorigenesis of Primary Adenocarcinoma of the Small Intestine

Twenty-four cases of primary nonampullary small intestinal adenocarcinoma were immunohistochemically examined for the expression of cytokeratin (CK) 7 and CK20 and compared with 23 colorectal adenocarcinomas secondarily involving the small intestine by direct extension or metastasis. While normal small intestinal mucosa was diffusely positive for CK20 and completely negative for CK7 expression, all small intestinal adenocarcinomas (24 of 24) showed a variable degree of CK7 expression. Specifically, the CK7 staining pattern was diffuse in 13 cases (54%) and focal in the remaining cases. Sixteen small intestinal adenocarcinomas (67%) coexpressed CK7 and CK20, and 8 (33%) completely lost CK20 immunoreactivity when compared with adjacent non-neoplastic small intestinal mucosa. In the latter cases, the loss of CK20 immunoreactivity with a reciprocal emergence of CK7 expression was evident. This was in contrast to secondary colorectal adenocarcinomas where 22 cases (96%) expressed CK20, among which only 1 case showed focal CK7 expression. The remaining 1 case was negative for both CK7 and CK20. Interestingly, adenomatous epithelium associated with small intestinal adenocarcinomas identified in 18 cases also exhibited CK7 positivity with a sharp transition from CK7-negative normal-appearing epithelium. Taken together, these observations delineate an alteration of CK7 and CK20 expression profile that occurs early in small intestinal tumorigenesis. This unique pattern may be of diagnostic value in distinguishing primary small intestinal adenocarcinoma from secondary colorectal adenocarcinoma.

Clinicopathologic features and endoscopic resection of early primary nonampullary duodenal carcinoma

Early primary nonampullary duodenal carcinoma is an extremely rare disease with poorly defined clinicopathologic features; early detection of this carcinoma is not common. To clarify the clinicopathologic characteristics of early primary nonampullary duodenal carcinoma and retrospectively analyze methods of treatment. Seventeen early duodenal carcinomas identified between 1994 and 2001 in 15 patients were studied. Lesions were divided into 2 groups: sporadic carcinoma (10 cases in 10 patients) and familial adenomatous polyposis associated carcinoma (7 cases in 5 patients). Clinicopathologic features and methods of treatment were compared between groups. The mean age of patients with sporadic carcinoma (63.8 years) was significantly higher than that of patients with FAP-associated carcinoma (34.9 years). The incidence of sporadic carcinoma was significantly higher in men that in women (M:F ratio 9:1); the difference between sexes in the incidence of FAP-associated carcinoma (1:4) was not significant. There was no significant difference between both groups in relation to tumor size, location, gross appearance, or histopathology. Thirteen of the duodenal tumors were treated by endoscopic mucosal resection (EMR), two by polypectomy, and two by open surgery. Complications were encountered in 1 of 15 cases (6%); local bleeding occurred after one EMR, but hemostasis was achieved endoscopically. The mean follow-up period for all patients was 51.7 months. No patients experienced recurrence after resection. The significant differences between patients with sporadic and those with early FAP-associated duodenal carcinoma were in age and sex. Endoscopic resection appears to be a safe and efficient treatment of carefully selected patients with early primary nonampullary duodenal carcinoma.

Microsatellite instability and expression of MLH1 and MSH2 in carcinomas of the small intestine

BACKGROUND

Carcinomas of the small intestine are rare, but the risk is greatly increased in patients with hereditary nonpolyposis colorectal cancer (HNPCC) due to an inherited mismatch repair (MMR) gene mutation, most commonly affecting the genes MLH1 or MSH2. Defective MMR is characterized by microsatellite instability (MSI) and loss of MMR protein expression in the tumor tissue. However, a subset of several sporadic tumor types, including about 15% of colon cancers, also evolve through defective MMR.

METHODS

The authors have assessed the frequency of MSI and analyzed the immunohistochemical expression of MLH1 and MSH2 in a population-based series of 89 adenocarcinomas of the small intestine. To study the contribution of MSI and defective MMR protein expression in young patients, 43 cancers of the small intestine from patients below age 60 years (including 24 tumors from the population-based series and an additional 19 tumors from young individuals) were also analyzed.

RESULTS

MSI was detected in 16/89 tumors (18%) in the population-based series, and immunohistochemistry revealed loss of expression for MLH1 in 7/16 MSI tumors and in 2/73 MSS tumors, whereas all tumors showed normal expression for MSH2. Among the young patients, the authors identified MSI in 10/43 tumors (23%), and 6 of these 10 MSI tumors showed immunohistochemical loss of MMR protein expression, which affected MLH1 in 3 cases and MSH2 in 3 cases.

CONCLUSIONS

The frequency of MSI (18%) in adenocarcinomas of the small intestine equals that of colon cancer. However, silencing of MLH1 seems to explain the MSI status in only about half of the MSI tumors. Among patients with cancer of the small intestine before age 60 years, MSI is found in 23% of the cases, with MLH1 and MSH2 being affected at equal frequencies, indicating that HNPCC may underly a subset of such cases.

COX-2, inflammatory secreted PLA2, and cytoplasmic PLA2 protein expression in small bowel adenocarcinomas compared with colorectal adenocarcinomas

Cyclooxygenase-2 (COX-2), human synovial inflammatory secreted phospholipase A2 (sPLA2) and cytoplasmic phospholipase A2 (cPLA2) are involved in eicosanoid production and also seem to participate in colorectal tumorigenesis. As there are no data regarding these enzymes in human small bowel tumors, we wanted to determine whether they were involved in human small bowel tumorigenesis, and whether their expression was different in small bowel compared to colorectal adenocarcinomas, as suggested by animal studies. We studied their protein expression by immunohistochemistry in 25 small bowel adenocarcinomas and compared it to 48 colorectal adenocarcinomas. Seventy-six percent of the small bowel and 88% of the colorectal adenocarcinomas had a moderate or strong COX-2 expression. Sixty-eight percent of the small bowel and 67% of the colorectal adenocarcinomas had a moderate or strong sPLA2 expression. Forty-eight percent of the small bowel and 35% of the colorectal adenocarcinomas had a moderate or strong cPLA2 expression. In conclusion, the increased expression of COX-2, sPLA2, and sometimes cPLA2 in both small bowel and colorectal adenocarcinomas is in accordance with the likely eicosanoid involvement in tumor development. The same pattern of protein expression found in both types of adenocarcinoma contradicts experimental results in mice. Moreover, our results strengthen the similarities between these two types of human cancer.

Histological evaluation of preoperative biopsies from ampulla vateri

Frequency of the lesions of the papilla Vateri is increasing in Hungary because of epidemiological reasons. Over two years nearly 300 ampullary endoscopic biopsies were taken in our hospital. In 36 percent of the patients the papillary specimens demonstrated acute or chronic inflammation, in 44 percent adenoma, including 5 percent with severe dysplasia, in 5 percent adenomatous hyperplasia and in 7 percent adenomyosis or other benign tumors (2%) were found. Around 7 percent of the ampullary samples proved to be malignant, but only in 2.6 percent were the malignancy of intraampullary origin. Nearly 25 percent of biopsies were repeated once and 10 percent twice or more. Concordance of endoscopic and pathologic diagnoses was 69 percent on average but it increased to 83 percent after including repeated biopsies. In the adenoma-carcinoma group the concordance was 90 percent. The sensitivity of the pathological diagnosis with forceps biopsy was only 77 percent, but it became at least 86 percent following papillectomy. In order to improve diagnostic reliability more extensive use of papillectomy is proposed with close cooperation between the endoscopist and pathologist.

Celiac disease and other precursors to small-bowel malignancy

Small-intestinal malignancies are rare. Major risk factors for the development of these malignancies include celiac disease, which predisposes to both carcinoma and lymphoma. Crohn's disease patients have an increased risk of the development of adenocarcinoma, as do the inherited polyposis syndromes, FAP, and Peutz-Jehgers syndrome. Each of these conditions provides unique models for the development of malignancy.

Small intestinal neoplasms

Small intestinal neoplasms are uncommonly encountered in clinical practice. They may occur sporadically, in association with genetic diseases (e.g., familial adenomatous polyposis coli or Peutz-Jeghers syndrome), or in association with chronic intestinal inflammatory disorders (e.g., Crohn's disease or celiac sprue). Benign small intestinal tumors (e.g., leiomyoma, lipoma, hamartoma, or desmoid tumor) usually are asymptomatic but may present with intussusception. Primary malignancies of the small intestine-including adenocarcinoma, leiomyosarcoma, carcinoid, and lymphoma-may present with intestinal obstruction, jaundice, bleeding, or pain. Extraintestinal neoplasms may involve the intestine via contiguous spread or peritoneal metastasis. Hematogenous metastases to the intestine from an extraintestinal primary are unusual and are most typical of melanoma. Because the small intestine is relatively inaccessible to routine endoscopy, diagnosis of small intestinal neoplasms is often delayed for months after onset of symptoms. When the diagnosis is suspected, enteroclysis is the most useful imaging study. Small bowel endoscopy (enteroscopy) is increasingly widely available and may permit earlier, nonoperative diagnosis.

A phenotypic change of small intestinal epithelium to colonocytes in small intestinal adenomas and adenocarcinomas

OBJECTIVE

Using a novel monoclonal antibody (mAb Das-1) that specifically reacts with colon epithelium, we examined if there is a phenotypic change of small intestinal enterocytes toward colonocytes in small intestinal neoplastic tissue.

METHODS

Tissue sections of the small intestine consisting of adenomas (n = 20, five with histories of familial polyposis), adenocarcinomas (eight primary and one metastatic from colon). carcinoids (n = 2), and hyperplastic polyps (n = 3) were examined by a sensitive immunoperoxidase assay using mAb Das-1 (IgM isotype). Normal jejunal (n = 10) and colonic (n = 10) biopsy specimens were also included as additional controls.

RESULTS

mAb Das-1 reacted with normal colonic epithelium but not with jejunal mucosa. However, mAb Das-1 reacted strongly with each of the five adenomas (100%) from patients with histories of familial polyposis, but only five of 15 (33%) of the adenomas from nonfamilial polyposis patients, and each of the eight (100%) adenocarcinomas of the small intestine (p < 0.001). The reactivity with the adenomas from nonfamilial polyposis patients was very focal, whereas in the adenomas with familial polyposis the reactivity was more extensive. Each of the eight carcinomas reacted strongly with mAb Das-1. Adjacent normal small intestinal mucosa did not react. Hyperplastic polyps and the carcinoids did not react with mAb Das-1.

CONCLUSION

These data demonstrate a phenotypic change in small intestinal epithelium toward the colonic phenotype, particularly in familial polyposis and in adenocarcinomas. mAb Das-1 may be clinically useful in identifying small intestinal adenomas with "high risk" for malignancy, such as in familial polyposis.

Risk factors for adenocarcinoma of the small intestine

We have investigated the relation between alcohol, tobacco and dietary habits and risk of adenocarcinoma of the small intestine using data from 2 hospital-based case-control studies on intestinal cancers conducted in 6 Italian centres between 1985 and 1996. Cases were 23 patients below age 75 years with adenocarcinoma of the small intestine. Controls were 230 patients admitted to hospital for a wide spectrum of acute, non-neoplastic, non-digestive tract diseases, matched to cases on sex, age, study and centre. Odds ratios (ORs) were estimated using conditional logistic regression. Alcohol and tobacco consumption did not increase the risk of adenocarcinoma of the small intestine. The risk appeared to be directly related to intake of bread, pasta or rice (OR = 3.8), sugar (OR = 2.9) and red meat (OR = 4.6), and inversely to coffee (OR = 0.4), fish (OR = 0.3), vegetables (OR = 0.3) and fruit (OR = 0.6). Our results suggest that dietary correlates of adenocarcinoma of the small intestine are similar to those of colon cancer and at least of the same magnitude. While the present data are inconsistent with a major effect of tobacco or alcohol, a moderate association between these factors and small bowel cancer may have been obscured by the play of chance.

Monoclonal antibody Adnab-9 defines a preneoplastic marker in epithelium at risk for adenocarcinoma of the small intestine

Unlike colorectal cancer, risk markers for adenocarcinoma of the small intestine (ASI) have not been identified. Because the demographic and pathological features of both of these diseases are similar, immunohistochemistry was performed using monoclonal antibodies for three colonic premalignant markers, Adnab-9 (recognizes a colonic adenoma epitope), CaCo3/61, and FBB2/29 (small intestine proteoglycans expressed ectopically in colonic neoplasms), in normal and neoplastic small intestinal epithelium, and the results were compared with normal controls. Adnab-9 was also examined in 20 familial adenomatous polyposis (FAP) patients, a population known to be at an increased risk for ASI. Immunohistochemistry in normal and neoplastic tissue (adenoma, adenocarcinoma) from 18 patients with primary adenocarcinoma of the small intestine was compared with normal small intestine from 10 nonneoplastic controls. Four of 10 (40%) cases of normal small intestinal epithelium from controls were mildly positive in less than 10% of crypts, versus strong staining (>50% of crypts) in 16 of 18 (89%) patients with adenocarcinoma, and in 17 of 20 (85%) patients with FAP (P<.05). Adnab-9 predominantly stained Paneth cells as well as rare crypt and basal villous goblet cells. Adenomatous epithelium from the adenocarcinoma cases and adenomas from the FAP patients showed staining of Adnab-9 in 63% and 78% of cases, respectively. Only 17% of adenocarcinomas were positive for Adnab-9. In contrast, neither CaCo3/61 nor FBB2/29 showed any significant differences in the degree of staining in normal small intestinal epithelium in patients with adenocarcinoma compared with controls. Enhanced Adnab-9 staining in normal small intestinal epithelium from patients who harbor adenocarcinoma, and in FAP patients, supports its role as a risk marker of small intestinal neoplasia.

Upper gastrointestinal disease in patients with familial adenomatous polyposis

BACKGROUND

Upper gastrointestinal disease has become an important aspect in the management of patients with familial adenomatous polyposis (FAP).

METHODS

A review of the literature was carried out using Medline. Epidemiology, pathology and treatment options are considered.

RESULTS AND CONCLUSION

Despite the fact that over 90 per cent of patients with FAP develop duodenal adenomas, only 5 per cent go on to develop cancer. In the absence of methods to detect who is at risk of cancer, all patients undergo regular endoscopic surveillance at present. Chemoprevention in the form of drug therapy may be the answer to controlling the disease.

Frequent K-ras mutations in small bowel adenocarcinomas

The reasons for the relatively rare occurrence of small bowel adenocarcinomas when compared to the high frequency of colonic adenocarcinomas are unknown. Activating mutations in the K-ras oncogene occur in about 40% of colonic adenocarcinomas, possibly reflecting the consequences of carcinogenic exposure. To study whether the low incidence of small bowel adenocarcinomas might be due to the absence of activation of cellular oncogenes in small bowel adenocarcinomas, we examined the frequency of K-ras mutations in small bowel adenocarcinomas. K-ras mutations were determined using a polymerase chain reaction (PCR)-based method to detect codon 12 mutations by restriction fragment length polymorphism. PCR amplification was successful in six of nine small bowel adenocarcinoma samples, and revealed point mutations of K-ras at codon 12 in five of these six cases. We conclude that the small bowel might be exposed to carcinogens similar to those responsible for colorectal cancer, but may have developed protective mechanisms against cancer formation.

Primary duodenal carcinoma

Eight cases of primary duodenal carcinoma in a district general hospital are presented. The cases highlight the advanced state of the disease at presentation, the difficulty in diagnosis, and its poor prognosis. Duodenal carcinoma occurs in both sexes worldwide with no predisposing factors in the majority of cases. There is an increased risk in patients with familial adenomatous polyposis and adenomas of the duodenum. Duodenal carcinoma occurs about 22 years from the diagnosis of familial adenomatous polyposis in about 2% of patients, forming over 50% of upper gastrointestinal cancers occurring in these patients. Carcinomatous changes occur in 30 to 60% of duodenal villous adenomas and much less in tubulo-villous and tubular adenomas. These categories of patients should be screened and adequately followed up. Aggressive and radical surgery, even in the presence of locally advanced disease and lymph node involvement, gives a better outcome. When curative surgery is not possible, chemotherapy must accompany palliation with or without radiotherapy. Pre-operative chemotherapy may facilitate a curative radical resection. The general five-year survival is 17-33% but some centres have achieved a five-year survival of 40-60% with aggressive management of these patients.

ras-family gene mutations in neoplasia of the ampulla of Vater

Mutations in the first and second exons of Ha-, Ki- and N-ras oncogenes were investigated in 17 epithelial tumors of the ampulla of Vater by single-strand conformation polymorphism analysis and direct sequencing of DNA fragments amplified by polymerase chain reaction. The panel included 12 intestinal-type adenocarcinomas, 3 villous adenomas, 1 papillary carcinoma and 1 neuroendocrine carcinoma. Six cases (35%) contained ras mutations, affecting codon 12 of Ki-ras in 2 adenomas and 3 carcinomas, and of N-ras in 1 adenoma. All mutations were found in adenomas and among cancers with adenomatous areas, whereas none of the cases lacking adenomatous areas contained mutations. This suggested that ampullary cancers represent heterogeneous diseases with respect to the presence or absence of adenomatous areas and, among those with adenomatous areas, with respect to the presence of activated ras genes. Ki-ras mutated cases included 3 of 4 tumors which mainly involved the intraduodenal bile duct, thus suggesting that a proportion of Ki-ras-mutated ampullary cancers might correspond to those originating from the epithelium of the bile duct component of the ampulla.

Iatrogenic pancreatitis in familial adenomatous polyposis

The first case of a patient with familial adenomatous polyposis (FAP) who developed pancreatitis after routine screening and biopsy of the ampulla of Vater is described.

Surgical polypectomy of duodenal adenomas in familial adenomatous polyposis: experience of two European centres

Between 1978 and 1988, 12 patients with familial adenomatous polyposis (FAP) and severe duodenal polyposis underwent duodenotomy and duodenal polypectomy. The patients were from two separate institutions; all were women, with a mean age of 45.6 (range 25-62) years at the time of duodenotomy. Recurrent duodenal polyposis was detected at endoscopy in all 12 patients, at a mean of 13.3 (range 5-36) months after duodenotomy. All patients had moderate to severe duodenal polyposis at the time of the last endoscopic examination. Local excision of duodenal adenomas is an unsatisfactory treatment option in those with FAP. The ideal management of patients with FAP who have severe duodenal polyposis remains uncertain.