The risk of cancer among patients with cystic fibrosis. Cystic Fibrosis and Cancer Study Group

Treatment of Gastrointestinal Problems in Cystic Fibrosis

The gastrointestinal (GI) manifestations of cystic fibrosis (CF) are varied and include pancreatic insufficiency, meconium ileus, distal intestinal obstruction syndrome (DIOS), liver disease, and other less common manifestations. Treatment of pancreatic insufficiency consists of providing appropriate pancreatic enzyme replacement therapy and may include raising duodenal pH to allow for optimal action of these enzymes. Despite a number of pancreatic enzyme replacement products, malabsorption cannot be normalized. Management of DIOS depends on the severity of the symptoms; adequate hydration is very important. Polyethylene glycol solutions are being increasingly used. The precipitating cause of the episode of DIOS should be looked for so future episodes can be prevented. Liver disease is relatively silent and annual monitoring of liver function and status is recommended. Treatment is mainly supportive and the role of ursodeoxycholic acid in the prevention of cirrhosis needs to be better defined. Nutritional status is an important part of management of all GI and liver manifestations of CF. A team approach and the assistance of a registered dietitian are extremely valuable in managing the GI and liver manifestations of CF.

A one-generation cluster of malignant mesothelioma within a family reveals exposure to asbestos-contaminated jute bags in Naples, Italy

Substantial evidence supports the role of asbestos in malignant mesothelioma. Clustering for this malignancy among relatives not only suggests genetic susceptibility as a relevant component but also provides a clue to investigate non-occupational sources of exposure. We identified five cases of malignant mesothelioma within one family with exposure to asbestos experienced during childhood, as 'next door' residents of a workshop recycling asbestos-contaminated jute sacks in Naples, Italy. This cluster discloses the health risk in the reuse of bags that previously had contained asbestos. Furthermore, it emphasizes the role of asbestos in the genetic-environmental interaction issue of malignant mesothelioma.

Characterization of the neoplastic phenotype in the familial atypical multiple-mole melanoma-pancreatic carcinoma syndrome

BACKGROUND

Previous studies suggest that the familial atypical multiple-mole melanoma (FAMMM) syndrome may predispose affected families to nonmelanoma carcinomas, including adenocarcinoma of the pancreas. It has been found that many of these families harbor mutations in the CDKN2A gene on chromosome 9p21. The phenotypic expression of CDKN2A mutations in these families has not been characterized fully.

METHODS

The authors studied eight families that appeared to inherit multiple nevi, cutaneous melanomas, and pancreatic carcinomas in association with a CDKN2A germline mutation. The expression of disease within these families was examined, and segregation ratios were estimated to assess the patterns of inheritance according to various definitions of phenotype.

RESULTS

Either multiple nevi or pancreatic carcinoma was diagnosed in 53% of first-degree relatives of the probands. The offspring of parents affected with multiple nevi, melanoma, or pancreatic carcinoma were significantly more likely to be affected themselves compared with the offspring of unaffected parents (48.9% vs. 16.7%; P = 0.004).

CONCLUSIONS

The current results provide additional evidence that multiple nevi, melanoma, or pancreatic carcinoma may be inherited as autosomal-dominant traits in families known to harbor CDKN2A mutations. Other malignancies may be a part of the phenotype in these families, although this hypothesis requires additional study.

Prenatal screening for cystic fibrosis

This article focuses on essential components related to prenatal screening for cystic fibrosis, including the clinical disease, inheritance, prognosis and treatment, birth prevalence, and ethnic variability. The molecular basis of this disease is presented, including a discussion of the gene, mutations, and genotype/phenotype correlations. The models that have been used for delivering prenatal screening services in pilot trials are described, along with lessons learned, expected screening performance, and relevant ELSI considerations. A realistic view of laboratory issues is considered, including current standards of performance, guidelines and oversight, and quality assurance. Examples of current laboratory technologies for cystic fibrosis testing are displayed.

Transition of care between paediatric and adult gastroenterology. Cystic fibrosis

Advancement in treatment has resulted in a dramatic increase in life expectancy of patients with cystic fibrosis (CF) to well beyond 30 years of age in most centres. What was once a fatal genetic disease in childhood now sees over a third of its CF populations in adult clinics. The improved survival is multifactorial, but most attribute the reasons to more aggressive nutritional care along with better management of the gastrointestinal and pulmonary systems. Many of the nutritional and GI issues of paediatric patients remain similar when they become adults, except that there is the added psychosocial stress associated with this transition. This chapter aims to highlight the gastrointestinal and nutritional issues manifesting at the different stages of life from infancy to adulthood, and the recommended management.

Cancer risk in nontransplanted and transplanted cystic fibrosis patients: a 10-year study

BACKGROUND

Cancer in patients with cystic fibrosis (CF), the most common genetic disorder in Caucasians, has been a rare event. However, more patients now reach adulthood, and more patients undergo organ transplantation-factors associated with an increased cancer risk. Our aim was to assess the risk of cancer in nontransplanted and transplanted CF patients.

METHODS

We followed 28 858 patients whose data were reported to the Cystic Fibrosis Foundation patient registry from 1990 through 1999 and compared the number of cancers observed in transplanted and nontransplanted patients to the number expected from population-based cancer incidence data. All statistical tests were two-sided.

RESULTS

In 202 999 person-years of observation of nontransplanted CF patients, 75 cancers were observed, but 69.7 were expected (standardized incidence ratio [SIR] = 1.1, 95% confidence interval [CI] = 0.8 to 1.4). Twenty-three digestive tract tumors were observed, but 4.5 were expected (SIR = 5.1, 95% CI = 3.2 to 7.6). More cancers than expected were observed of the small bowel, colon, and biliary tract but not of the stomach or rectum. We found that the deficit of non-digestive tract tumors was not statistically significant (52 observed versus 65.2 expected; SIR = 0.80, 95% CI = 0.6 to 1.0; P =.055). In 2725 person-years of observation of 1063 transplanted patients, 13 cancers were observed, but 2.05 were expected (SIR = 6.3, 95% CI = 3.4 to 10.8), and more digestive tract tumors (four observed versus 0.19 expected; SIR = 21.2, 95% CI = 5.8 to 54.2) and lymphomas (seven observed versus 0.16 expected; SIR = 44.0, 95% CI = 17.7 to 90.7) were observed than expected.

CONCLUSIONS

We observed an increased risk of digestive tract cancers among adult CF patients, particularly of the small bowel, colon, and biliary tract. This increased risk appeared to be more pronounced in patients who had had an organ transplantation.

GI complications after lung transplantation in patients with cystic fibrosis

STUDY OBJECTIVE

Lung transplantation is now available for patients with cystic fibrosis (CF) and end-stage lung disease. While pulmonary graft function is often considered the major priority following transplantation, the nonpulmonary complications of this systemic disease also continue. We examined the GI complications in a cohort of patients who underwent transplantation.

DESIGN

This was a retrospective study of all patients with CF who underwent transplantation between March 1988 and December 1998 in Toronto. Medical records were reviewed, and a short questionnaire was mailed to patients who were alive as of December 1998.

RESULTS

There were 80 bilateral lung transplants performed in 75 patients. The questionnaire was distributed to 43 patients, of whom 27 patients (63%) responded. Pancreatic insufficiency requiring enzyme intake was evident in 72 of 75 patients (96%) at the time of surgery. Of three pancreatic-sufficient patients (4%), pancreatic insufficiency was diagnosed in two patients later. Biliary cirrhosis was diagnosed in three patients prior to transplantation. Distal intestinal obstruction syndrome (DIOS) was recorded for 15 patients (20%). Ten patients had a single episode, of which eight episodes occurred early in the postoperative period. Five patients had recurrent episodes. All were medically treated, except for two patients who underwent surgery. Other complications included cholecystitis (n = 3), mucocele of the appendix (n = 1), peptic ulcer disease (n = 3), and colonic carcinoma (n = 1).

CONCLUSION

GI complications after lung transplantation are common in patients with CF, and attention should be paid to the risk for DIOS in the early postoperative period. Prevention and early medical treatment are important in order to avoid acute surgery. Close collaboration with the CF clinic, in order to diagnose and treat CF-related complications, is recommended.

Detection of oncogenes in chronic pancreatitis

BACKGROUND

The pathogenesis of chronic pancreatitis (CP) remains poorly understood. Recently, molecular biology has identified the genetic background for many patients with hereditary CP. In addition, a number of studies have focused on the detection of proto-oncogenes and tumour suppressor gene mutations in the pathogenesis of CP. So far, the use of these mutations (with the exception of mutations causing hereditary CP), as diagnostic and prognostic markers is still controversial.

DISCUSSION

It is well known that the risk of pancreatic cancer in patients with CP, especially the hereditary form, is high. At present, there is insufficient evidence to show a clear relationship between the development of pancreatic cancer and certain mutations. New biotechnological methods, such as DNA array expression analysis, expand our knowledge of the molecular pathogenesis of this disease and may help to develop specific diagnostic, prognostic and therapeutic tools. However, until long-term studies examine the safety and efficacy of certain genetic markers, long-term follow-up of patients with CP who harbour mutations is needed.

Gene-environment interactions in pancreatic cancer

Exocrine pancreatic cancer remains a major cause of cancer death in Western populations. Despite many efforts, little is known about its etiology. Tobacco is the only established cause, although the proportion of cases of exocrine pancreatic cancer attributed to it is only 30%. A family history of pancreatic cancer accounts for 10% of the cases of this disease. A large proportion of cases are due to yet unrecognized factors. The combined contribution of genetic susceptibility and environmental factors has rarely been considered. A higher risk of exocrine pancreatic cancer has been observed for patients with hereditary pancreatitis who smoked. It has also been suggested that CFTR mutations and alcohol could interact in the development of exocrine pancreatic cancer. Common variants in a large number of genes could act as low-penetrance alleles. Little is known about their role as susceptibility markers for exocrine pancreatic cancer, except for metabolic enzymes. A few studies have assessed the association between polymorphisms in these genes and exocrine pancreatic cancer. Surprisingly, none of them observed an interaction with tobacco consumption. The reality may be more complex; exocrine pancreatic cancer is genetically heterogeneous and it could involve many somatic and heritable mutations. Gene-gene interactions and endogenous factors, among others, can contribute to tumor development. Future epidemiological studies should consider all of these aspects together.

Molecular diagnosis of early pancreatic ductal adenocarcinoma in high-risk patients

The prevalence of pancreatic cancer in the general population is too low--even in high-prevalence areas such as Northern Europe and North America (8-12 per 10(5) population)--relative to the diagnostic accuracy of present detection methods to permit primary screening in the asymptomatic adult population. The recognition that the lifetime risk of developing pancreatic cancer for patients with hereditary pancreatitis (HP) is extremely high (20% by the age of 60 years and 40% by the age of 70 years) poses considerable challenges and opportunities for secondary screening in those patients without any clinical features of pancreatic cancer. Even for secondary screening, the detection of cancer at a biological stage that would be amenable to cure by surgery (total pancreatectomy) still requires diagnostic modalities with a very high sensitivity and specificity. Conventional radiological imaging methods such as endoluminal ultrasound and endoscopic retrograde pancreatography, which have proved to be valuable in the early detection of early neoplastic lesions in patients with familial pancreatic cancer, may well be applicable to patients with HP but only in those without gross morphological features of chronic pancreatitis (other than parenchymal atrophy). Unfortunately, most cases of HP also have associated gross features of chronic pancreatitis that are likely to seriously undermine the diagnostic value of these conventional imaging modalities. Pre-malignant molecular changes can be detected in the pancreatic juice of patients. Thus, the application of molecular screening in patients with HP is potentially the most powerful method of detection of early pancreatic cancer. Although mutant (mt) K-ras can be detected in the pancreatic juice of most patients with pancreatic cancer, it is also present in patients with non-inherited chronic pancreatitis who do not progress to pancreatic cancer (at least in the short to medium term), as well as increasingly in the older population without pancreatic disease. Nevertheless, the presence of mt-K-ras may identify a genuinely higher-risk group, enabling additional diagnostic imaging and molecular resources to be focussed on such a group. What is clear is that prospective multi-centre studies, such as that being pursued by the European Registry of Hereditary Pancreatitis and Familial Pancreatic Cancer (EUROPAC), are essential for the development of an effective secondary screening programme for these patients.

Inherited pancreatic cancer: surveillance and treatment strategies for affected families

BACKGROUND

Nearly 10% of pancreatic cancers are hereditary in origin, and in some individuals, the risk of pancreatic cancer approaches 50%. A number of defined syndromes can predispose families to pancreatic cancer, although many of the mechanisms that result in familial pancreatic cancers are unknown. This article reviews current knowledge regarding familial pancreatic cancers and highlights the rationale for screening and surveillance. Methods for screening and surveillance of these high-risk individuals are described that allow the detection of pancreatic dysplasia, the precursor to pancreatic cancer. We also describe a single-center experience with the management and surveillance of familial pancreatic cancer kindreds.

METHODS

Thirty-five patients from 13 familial pancreatic cancer kindreds underwent screening and/or surveillance. Endoscopic ultrasound (EUS) is the initial test of choice. Endoscopic retrograde cholangiopancreatography (ERCP) is reserved for symptomatic individuals or to investigate abnormal findings on EUS. In the proper clinical setting, patients with abnormal findings on both EUS and ERCP are candidates for total pancreatectomy.

RESULTS

Twelve of 35 patients were noted to have abnormal findings on EUS and ERCP. All of these individuals underwent pancreatectomy, 10 total and 2 partial. The patients who underwent partial pancreatectomy are currently awaiting resection of the pancreatic remnant. Histopathologic examination of all 12 specimens demonstrated pancreatic dysplasia (the precursor lesion to pancreatic cancer). These specimens had no evidence of pancreatic cancer; nor were any of the resected pancreata normal. Follow-up of the 35 high-risk patients at present varies from 1 to 48 months, and none of the patients under surveillance have developed pancreatic cancer.

CONCLUSION

The screening and surveillance of high-risk members of familial pancreatic cancer kindreds using EUS and ERCP is an effective method for identifying individuals with pancreatic dysplasia prior to the onset of invasive pancreatic cancer. The surveillance needs to be performed by a team of specialists who have experience in dealing with pancreatic cancer and its precursors.

Pancreatitis as a risk for pancreatic cancer

Chronic pancreatitis clearly predisposes to pancreatic cancer, with early onset-long duration chronic pancreatitis from cystic fibrosis, TP, and HP conferring the highest risk. Chronic pancreatitis is not a critical step, however, but rather one of several conditions that accelerate the accumulation of critical genetic mutations and chromosomal losses necessary for carcinogenesis. Indeed, other germline mutations, environmental factors such as tobacco smoking and alcohol consumption, or dietary factors may also accelerate the pathway to carcinogenesis, and may be synergistic with the conditions created by chronic pancreatitis. Because patients with chronic pancreatitis are at high risk of pancreatic cancer, the physician is faced with decisions on how to manage this risk. Discontinuing smoking and alcohol consumption, and perhaps dietary modification are obvious recommendations for risk reduction. If, however, the patient is older and already in a very high-risk category (e.g., long-standing HP), then screening for cancers must be considered. Inclusion in multicenter trials is recommended, and information on ongoing studies can be obtained through the office of Dr. Whitcomb, or as posted on www.pancreas.org.

Outpatient care of the cystic fibrosis patient after lung transplantation

Lung transplantation has become an accepted treatment for respiratory failure due to cystic fibrosis (CF). Effective means of patient selection, surgical technique, immunosuppression, and post-transplant management permit survival as good as that of transplant patients with other diseases. The new lungs do not acquire the CF ion transport abnormalities but are subject to the usual post-transplant complications. CF problems in other organ systems persist and may be worsened by some of the immunosuppressive regimens. Prolonged survival increases the risk of age-related CF and other complications. Effective medical management requires expert knowledge of CF and lung transplantation and of how their problems interact, and good communications among the participating care teams.

Increased circulating levels of plasma ATP in cystic fibrosis patients

Recent studies have shown that the cystic fibrosis transmembrane conductance regulator (CFTR), an ATP-binding cassette (ABC) transporter whose mutations are responsible for cystic fibrosis (CF), permeates ATP. However, little information is available concerning extracellular ATP concentrations in CF patients. Thus, the goal of this preliminary study was to determine the circulating levels of plasma ATP in CF patients. Circulating levels of plasma ATP were determined by the luciferin-luciferase assay in both CF patients and healthy volunteer control subjects. The two groups were compared using an analysis of variance. CF genotype and age, which ranged from 7 to 56 years, were also used to compare data by single-blind analysis. With comparable sample numbers, CF patients had statistically higher levels of circulating ATP (34%, P<0.01) when compared by analysis of covariance with the age of the subjects as the cofactor. The CF patients bearing the DeltaF508 genotype had a 54% (n=33, P<0.01) higher plasma ATP concentration compared to controls, while patients bearing other CF genotypes were similar to controls (n=10, P<0.4). We conclude that CF patients have higher circulating levels of ATP when compared to controls. Increased levels of plasma ATP, which is an important autocrine/paracrine hormone in many cell types, may be associated with chronic manifestations of the disease.

Serum vascular endothelial growth factor is elevated in cystic fibrosis and decreases with treatment of acute pulmonary exacerbation

Chronic bacterial infection and neutrophilic inflammation characterize cystic fibrosis (CF) pulmonary disease. In many disorders, inflammation and angiogenesis are codependent phenomena. We previously noted excessive angiogenesis in CF tissues and elevated vascular endothelial growth factor (VEGF) in random serum samples from subjects with CF. To further explore this finding, we measured serum VEGF in 38 subjects with stable CF and in 25 subjects with other pulmonary diseases. Mean VEGF was elevated in both groups compared with reference values, but it was higher in CF: 403 +/- 280 versus 255 +/- 169 pg/ml, p = 0.02. VEGF was negatively correlated with FEV(1) in CF, r = -0.51, p = 0.007. To assess the effect of airway infection on VEGF, 10 subjects with CF were studied before and after intravenous antibiotic therapy for pulmonary exacerbation. VEGF levels decreased with antibiotic therapy, from 537 +/- 220 to 259 +/- 176 pg/ml, p = 0.001. We conclude that circulating VEGF is increased in subjects with CF and other inflammatory pulmonary disorders. In CF, VEGF elevation is related to airway infection. We speculate that increased circulating VEGF is related to chronic inflammation, which is robust in CF. Elevated circulating VEGF may result in tissue angiogenesis, furthering the progression of pulmonary disease.

Cancer surveillance of patients from familial pancreatic cancer kindreds

The family history can be used to determine which family members warrant surveillance and when to start it. Surveillance should be started at least 1 decade before the earliest age of pancreatic cancer in the family. EUS is the basic, least-invasive surveillance tool; however, findings are similar to those seen in chronic pancreatitis. All patients who have a positive EUS or who have symptoms warrant ERCP. Changes on ERCP of ductal stricturing and clubbed or saccular side branches are suggestive of patients who may need pancreatectomy in the setting of hereditary pancreatic cancer. The goal for surveillance of familial pancreatic cancer patients is to diagnose them before the development of cancer, when they have dysplasia or carcinoma in situ, and to perform a complete pancreatectomy. Timing is crucial for determining when a patient warrants surgery; if performed too early, the patient is put at risk for the morbidity and mortality of a total pancreatectomy, which is not inconsequential. If the patient survives the operation, he or she is often left a brittle diabetic. The alternative of diagnosing too late is more worrisome because the patient dies of pancreatic cancer. An essential ingredient to a good patient outcome is a team approach to these patients, using gastroenterologists, surgeons, and pathologists who have expertise and interest in pancreatic disease.

Growth factors, receptors, and molecular alterations in pancreatic cancer. Putting it all together

Because of the dismal prognosis of advanced ductal pancreatic adenocarcinoma, recent investigational strategies have focused on improved detection and therapeutic intervention in early-stage pancreatic cancer. The obvious cost constraints of screening populations at risk but with a low tumor yield will restrict screening protocols to only the highest risk groups (hereditary pancreatitis = age 50, certain hereditary pancreatic cancer kindreds). The vast majority of patients, either lacking or exhibiting an inherited predisposition to pancreatic cancer, will continue to present with disease not resectable for cure. The authors believe that the best hope for these patients lies in the further delineation of the integrative pathophysiology driving tumor growth; this would facilitate the future development of a computer program or other modality that would predict the dominant pathways driving the growth and spread of each tumor based on its "molecular profile." This article reviews the authors' current knowledge regarding the growth factors, receptors, and molecular alterations driving uncontrolled proliferation, local invasion, and metastatic spread of these tumors. The current and potential contributions of studies in cohorts with an inherited predisposition to pancreatic cancer to this pathophysiologic model are also discussed. The future strategy for incorporating this information into a working pathophysiologic road map with clinical relevance is subsequently outlined.

Evidence of chronic inflammation in morphologically normal small intestine of cystic fibrosis patients

Cystic fibrosis (CF) is caused by mutations in the CF transmembrane conductance regulator gene and characteristically leads to prominent lung and pancreatic malfunctions. Although an inflammatory reaction is normally observed in the CF airways, no studies have been performed to establish whether a chronic inflammatory response is also present in the CF intestine. We have investigated whether immunologic alterations and signs of inflammation are observed in CF small intestine. Fourteen CF, 20 negative, and four disease controls underwent duodenal endoscopy for diagnostic purposes. Two CF patients were rebiopsied, one after 3 mo of an elemental diet and the other after 2 wk of pancreatic enzyme withdrawal. In three CF and 10 controls, in vitro small intestine organ cultures were also performed. Expression of ICAM-1, IL-2 receptor, IL-2, IFN-gamma, CD80, and transferrin receptor was studied by immunohistochemistry before and after in vitro organ culture. In CF small intestine, an increased number of lamina propria mononuclear cells express ICAM-1 [mean 114 (SD 82.8), p < 0.001 versus controls], CD25 [20.2 (18.7), p < 0.01], IL-2 [23.6 (13.7), p < 0.05], and IFN-gamma [19 (15.9), p < 0.05], whereas villus enterocytes highly express transferrin receptor. Reduced expression of immunologic markers was observed after 24 h of in vitro culture in all three CF patients as well as in the patient kept on elemental diet for 3 mo. These results indicate that chronic inflammation is observed in CF duodenum and suggest that the perturbation of local mucosal immune response may contribute to the overall clinical picture in CF patients.

Unique presentations and chronic complications in adult cystic fibrosis: do they teach us anything about CFTR?

The increase in numbers of adults with cystic fibrosis (CF) has allowed us to identify previously unrecognized chronic complications of CF, as well as appreciate unique presentations of cystic fibrosis-related diseases. Do these chronic complications and unique presentations provide us with new insight into cystic fibrosis transmembrane conductance regulator (CFTR) function? Current data suggest that the 'chronic complications' reveal mainly the effect of a long-term absence of previously recognized CFTR functions. In contrast, the 'unique presentations' provide new insight into the role of CFTR in different tissues.

Epidemiologic study of cystic fibrosis: design and implementation of a prospective, multicenter, observational study of patients with cystic fibrosis in the U.S. and Canada

Cystic fibrosis (CF) is a complex illness characterized by chronic lung infection leading to deterioration in function and respiratory failure in over 85% of patients. An understanding of the risk factors for that progression and the interaction of these factors with current therapeutic strategies should materially improve the prevention of this progressive lung disease. The Epidemiologic Study of Cystic Fibrosis (ESCF) was therefore designed as a multicenter, longitudinal, observational study to prospectively collect detailed clinical, therapeutic, microbiologic, and lung function data from a large number of CF treatment sites in the U.S. and Canada. The ESCF also serves an important role as a phase-IV study of dornase alfa. To be eligible for enrollment, subjects must have the diagnosis of CF and receive the majority of their care at an ESCF site. In this paper, the authors present the ESCF study design in detail. Further, enrollment data collected at 194 study sites in 18,411 subjects enrolled from December 1, 1993 to December 31, 1995 are presented in summary form. This comprehensive study is unique in the detail of clinical data collected regarding patient monitoring and therapeutic practices in CF care. Two companion articles present data regarding practice patterns in cystic fibrosis care, including data on resource utilization and prescribing practices.

Chronic pancreatitis and other risk factors for pancreatic cancer

Pancreatic cancer is the fourth or fifth most common form of cancer in Western countries. Early diagnosis is difficult and the overall mortality rate is high. Individuals at high risk for pancreatic cancer include smokers, African-Americans, and persons with various types of pancreatitis. As with other cancers, dietary factors play an important role. Approximately 10% of all pancreatic tumors may be related to an inherited germ line disorder.

An unusual cause of rectal bleeding in a patient with cystic fibrosis

Here we identify a previously unreported cause of rectal bleeding (juvenile polyposis) in a patient with cystic fibrosis (CF). We believe this patient most likely has two coexisting genetic diseases. It also raises many issues about organ transplantation in a patient with medical conditions that individually increase the risk of gastrointestinal malignancy and stresses the diagnostic value of endoscopy in CF patients with rectal bleeding.

CFTR deltaF508 carrier status, risk of breast cancer before the age of 40 and histological grading in a population-based case-control study

There has been recent interest in the risk of various cancers in cystic fibrosis (CF) patients and carriers of cystic fibrosis transmembrane conductance regulator (CFTR) mutations. It has been proposed that a CFTR mutation may protect against breast cancer, based on evidence that elevated extracellular adenosine triphosphate (ATP) is known to inhibit breast cancer cell line growth and that CFTR pumps ATP out of epithelial cells. A CFTR mutation would therefore result in higher concentrations of serum ATP. A CFTR knockout mouse model had high serum concentrations of ATP and showed reduced breast tumour implantibility and decreased breast cancer growth rates. We have evaluated the relationship between the deltaF508 CFTR mutation and the risk of breast cancer before the age of 40. The deltaF508 CFTR mutation carrier rate in 272 cases (2.2%) was no different from the carrier rate observed in 171 controls (1.8%). If there was a protective effect resulting from the postulated elevation in serum ATP levels, tumours arising in deltaF508 CFTR carriers would have been expected to be generally less aggressive. When the histological features of the breast cancers with a deltaF508 CFTR mutation were reviewed and graded using a combined architectural and cytological grading system, all were found to be grade III, poorly differentiated tumours, contrary to the predictions. A combination of our data with other large population-based samples of cases and controls is required to resolve this issue.

Lung transplantation in cystic fibrosis: consensus conference statement

The first successful heart-lung and lung transplant operations in cystic fibrosis (CF) patients were performed in 1983 and 1987, respectively. Lung transplantation is now available at dozens of centers in North America, Europe, and Australia. Recent technical developments and the major limitations of donor organ availability prompted the CF Foundation to sponsor a meeting of 37 experts to evaluate the state of the art in lung transplantation for CF, highlighting areas of consensus, practice variations, and controversy. This document summarizes the work of that group.

Etiologic links between chronic pancreatitis and pancreatic cancer

In all forms of pancreatitis there appears to be a cellular dysfunction, glandular destruction, and, presumably, increased cell turnover. Increased cell division has been suggested as a potential precursor of cancer in many organs. The excess risk of pancreatic cancer that has been documented in epidemiologic studies in patients with various types of pancreatitis is consistent with this hypothesis. The uncertainties in epidemiologic studies notwithstanding, the existence of a clear association between pancreatitis and the subsequent risk of pancreatic cancer is found too often to be only randomized. The clinical relevance of a causal relationship between chronic pancreatitis and pancreatic cancer is, however, limited, since the prognosis of chronic pancreatitis cannot be separated from that of chronic alcoholism.

Neuropathy and vasculopathy in colonic strictures from children with cystic fibrosis

Colonic strictures are rare in patients who have cystic fibrosis, but recently have developed in those who have been treated with delayed-release high-dose pancreatic enzyme supplements. Colonic strictures from eight such pediatric patients showed neural abnormalities consisting of ganglion cell hyperplasia and ectopia, and intermyenteric plexus hyperplasia. Cholinergic and adrenergic stains of mucosal nerve fibers were more prominent in histological sections of the cystic fibrosis strictures than in sections from colons of children without cystic fibrosis. The mean grade of staining with acetylcholinesterase in the lamina propria of the strictured cystic fibrosis colons was 2.38 +/- 1.25, compared with .93 +/- .93 (P < .055) in bowels from children without cystic fibrosis. The mean grade for tyrosine hydroxylase staining in the lamina propria was 2 +/- .97 in the strictures and was .79 +/- .81 (P < .05) in the bowels of children who did not have cystic fibrosis. Vasoactive intestinal peptide staining in bowels from children with cystic fibrosis with and without stricture did not differ significantly from that of children without cystic fibrosis. Vasculopathy consisting of fibrointimal hyperplasia in submucosal veins and mesenteric arteries was found only in colonic strictures owing to cystic fibrosis. Colonic strictures in patients with cystic fibrosis who received high-dose pancreatic enzyme supplements contain ganglion cell abnormalities, and mucosal cholinergic and adrenergic activity may be increased in these strictures. The stricture vasculopathy may be drug-related and/or related to increased catecholamine activity.

Cystic fibrosis hetero- and homozygosity is associated with inhibition of breast cancer growth

Cystic fibrosis (CF) is the most common lethal recessive genetic disease of the Caucasian population. Although reports of cancer frequency in CF have emphasized an elevated observed-to-expected ratio of 6.5 for digestive tract cancers, these studies also show a significantly decreased observed-to-expected ratio for other malignancies including breast cancer. The cystic fibrosis transmembrane conductance regulator (CFTR) functions as an ATP channel. We found that heterozygous and homozygous CFTR knockout mice had elevated blood ATP concentrations. Elevated extracellular ATP is known to inhibit tumor growth in vivo and in vitro. Using double mutant mice created by F2 generation crosses of CFTR knockout and nude mice, we observed reduced breast tumor implantability in CFTR homozygous nude animals. Decreased tumor growth rate was observed in both CFTR heterozygous and homozygous nude animals. Extracellular ATP reduced human breast tumor cell growth rate in vitro, and a breast tumor transfected with human CFTR that had high extracellular ATP concentrations in vitro correspondingly had a slower growth rate in vivo. The results suggest that both CFTR heterozygosity and homozygosity suppress breast cancer growth and that elevated extracellular ATP can account for this phenomenon.

Case report: cystic fibrosis and embryonal carcinoma of the testis

The authors describe a patient with cystic fibrosis and a stage III testicular embryonal cell cancer. Because cystic fibrosis occurs in approximately 1 of 2,500 births and embryonal carcinoma in 3 of 100,000, the likelihood of concurrence for both disorders in the same patient is approximately 1 in 80 million. Involvement of the vas deferens in cystic fibrosis raises the possibility of a fundamental embryologic basis that explains the pathogenesis of this association.

Cystic fibrosis. Gastrointestinal complications and gene therapy

The gastrointestinal and nutritional complications of cystic fibrosis are diverse. As longevity improves in patients with cystic fibrosis, management of these complications is becoming increasingly important . This article provides overviews of the molecular aspects of the pathogenesis of cystic fibrosis, the current status of gene therapy, and a review of the gastrointestinal manifestations and nutritional care.