MUTYH hotspot mutations in unselected colonoscopy patients.

AIM: Biallelic MutY human homologue (MUTYH) germline mutations predispose to recessively inherited adenomatous polyposis, designated MUTYH-associated polyposis (MAP), and colorectal cancer (CRC). The hotspot mutations p.Y179C and p.G396D account for the majority of pathogenic variants of MUTYH in Caucasians. Our aim was to evaluate the prevalence of MUTYH mutations in a prospective cohort of unselected patients with different colorectal diseases. METHOD: The hotspot mutations p.Y179C and p.G396D were genotyped in 352 consecutive patients undergoing colonoscopy at our tertiary referral centre. Exons 2-14 were sequenced in hotspot mutation carriers to exclude additional variants. RESULTS: Overall, we identified five heterozygous p.Y179C mutations and three heterozygous p.G396D mutations in seven hotspot mutation carriers (risk allele frequencies 0.7% and 0.4%, respectively). Two of these hotspot mutation carriers harboured a heterozygous p.Q338H variant, which is of uncertain clinical significance, on the other allele. Three individuals were biallelic MUTYH variant carriers (p.Y179C/p.G382D: typical MAP; p.Y179C/p.Q338H: atypical MAP with late onset and lower polyp burden; p.G382D/p.Q338H: inflammatory bowel disease), and four subjects were monoallelic mutation carriers. CONCLUSION: MUTYH-associated disease, and hence genetic counselling and MUTYH genetic testing, should be considered in the clinical routine of an endoscopy unit, but the wide range of phenotypes represents a challenge for patient identification. The clinical significance of p.Q338H should be evaluated in future case-control studies because compound heterozygotes for pathogenic mutations and p.Q338H may be at increased risk for mild polyposis or CRC. In addition, MUTYH should be assessed as a potential susceptibility gene for the development of colitis-associated CRC in future.

A randomized multicenter phase II study comparing capecitabine with irinotecan or cisplatin in metastatic adenocarcinoma of the stomach or esophagogastric junction.

BACKGROUND: The combination of irinotecan with 5-fluorouracil demonstrates efficacy with tolerable safety in the first-line treatment of metastatic gastroesophageal cancer (mGC). This randomized phase II trial compared for the first time capecitabine with irinotecan or cisplatin in this setting. PATIENTS AND METHODS: Patients were randomly assigned to receive 3-week cycles of capecitabine 1000 mg/m(2), twice daily for 14 days, with on day 1 either irinotecan 250 mg/m(2) (XI) or cisplatin 80 mg/m(2) (XP). The primary end point was overall response rate (ORR) and secondary end points included progression-free survival (PFS), overall survival (OS) and safety. RESULTS: Of 118 patients recruited, 112 were eligible for safety analysis and 103 for efficacy analysis. In the XI and XP treatment arms, there were no marked differences in ORR, 37.7% versus 42.0%, and median PFS, 4.2 versus 4.8 months, although median OS was longer, 10.2 versus 7.9 months, respectively. Grade 3/4 toxicity was higher in the XP regimen for thrombocytes (18.2% versus 1.8%), nausea (23.6% versus12.3%) and vomiting (16.4% versus 1.8%) and in the XI arm for diarrhea (22.8% versus 7.3%). CONCLUSION: The comparable activity and safety of the XI and XP regimens establish XI as a relevant platinum-free first-line treatment choice for patients with mGC.

Para-[(123)I]iodo-L-phenylalanine in patients with pancreatic adenocarcinoma: tumour uptake, whole-body kinetics, dosimetry.

UNLABELLED: Recently, p-[(123)I]iodo-L-phenylalanine (IPA) was clinically validated for brain tumour imaging. Preclinical studies demonstrated uptake of IPA into pancreatic adenocarcinoma suggesting its diagnostic application in patients with pancreatic tumours. The aim was to study the tumour uptake of IPA in patients with pancreatic adenocarcinoma and to analyse its biodistribution and dosimetry to assess the radiation dose resulting from its diagnostic use. PATIENTS, METHODS: Seven patients with pancreatic adenocarcinoma underwent whole-body scintigraphies and SPECT up to 24 h after administration of 250 MBq of IPA. Tumour uptake of IPA was assessed visually. Time activity curves and the corresponding residence times were determined for whole-body, kidneys, liver, spleen, lung, heart content, brain, and testes. Mean absorbed doses for various organs and the effective dose were assessed based on the MIRD formalism using OLINDA/EXM. RESULTS: IPA exhibited no accumulation in proven manifestations of pancreatic adenocarcinomas. IPA was exclusively eliminated by the urine and showed a delayed clearance from blood. Residence times were 0.26 +/- 0.09 h for kidneys, 0.38 +/- 0.19 h for liver, 0.15 +/- 0.07 h for spleen, 0.51 +/- 0.20 h for lungs, 0.22 +/- 0.07 h for heart content, 0.11 +/- 0.05 h for brain, 0.014 +/- 0.005 h for testes and 6.4 +/- 2.2 h for the remainder. The highest absorbed doses were determined in the urinary bladder wall and in the kidneys. According to the ICRP 60 the effective dose resulting from 250 MBq IPA was 3.6 +/- 0.7 mSv. CONCLUSION: Para-[(123)I]iodo-L-phenylalanine can be used in diagnostic nuclear medicine with acceptable radiation doses. Besides its proven validity for brain tumour imaging, IPA does not appear to be suitable as tracer for pancreatic cancer.

Activation of a cryptic splice site of PTEN and loss of heterozygosity in benign skin lesions in Cowden disease.

Cowden disease is an autosomal dominant syndrome characterized by facial trichilemmomas, acral keratoses, papillomatous papules, mucosal lesions, and an increased risk for breast and nonmedullary thyroid cancer. Here, we describe a novel PTEN splicing site mutation in a family with classical Cowden disease and we studied benign skin lesions typical for Cowden disease for loss of heterozygosity. We found a PTEN IVS2 + 1G > Alpha 5'-splicing acceptor mutation resulting in activation of a cryptic splice site. Activation of this cryptic splice site is predicted to result in a frameshift with a premature stop codon, thus disrupting the phosphatase core motif of PTEN. Loss of heterozygosity analysis of two trichilemmomas, one fibroma, and three acanthomas of the index patient demonstrated loss of heterozygosity at the PTEN locus in four of these lesions. In conclusion, our data demonstrate that a PTEN splicing site mutation causes activation of a cryptic splice site, which results in aberrant transcripts.

Clinical evaluation of autoantibodies to p53 protein in patients with chronic liver disease and hepatocellular carcinoma.

In hepatocellular carcinoma (HCC) of patients from the Western hemisphere, mutations in the p53 tumour suppressor gene are present in up to 37% of cases. Conformational change and cellular accumulation can initiate an immune response with generation of circulating autoantibodies to p53 protein. In the present study, we investigated 711 consecutive patients with chronic liver disease to evaluate the sensitivity and specificity of autoantibodies to p53 protein as a serological marker for HCC. Detection of p53 autoantibodies was performed using an enzyme-linked immunosorbent assay with immobilised recombinant p53 protein. Liver cirrhosis was present in 259 patients (36.4%) and a HCC was diagnosed in 75 patients (10.6%). Autoantibodies to p53 protein were detectable in 15 of 377 patients with chronic liver disease (4.0%) and in 10 of 259 patients presenting with liver cirrhosis (3.9%). All 25 p53 autoantibody-positive/HCC-negative patients were carefully investigated and no underlying malignancy was clinically detected, suggesting that elevated p53 antibody levels may not exclusively be detectable in patients with malignant disease. In patients with clinically manifest HCC, p53 autoantibodies were detected in 17 of 75 cases, thus resulting in a sensitivity of 22.7% and a specificity of 96.1%. In contrast, assessment of serum alpha-fetoprotein (AFP) resulted in a sensitivity and specificity of 69.3 and 91.8% (AFP > 20 ng/ml) and 53.3 and 99.1% (AFP > 100 ng/ml) for the detection of HCC, respectively. The data of the present study reveal that the presence of p53 autoantibodies in patients with chronic liver disease is not completely specific for HCC. Moreover, we obtained no direct evidence that p53 autoantibody formation precedes the clinical diagnosis of HCC. However, serological screening for HCC might be improved by combining AFP and p53 autoantibody assays.

Rapid microsatellite analysis of paraffin embedded tumour specimens from patients with hereditary non-polyposis colorectal cancer.

In screening for hereditary non-polyposis colorectal cancer (HNPCC)--an autosomal dominant disorder characterised by mutations in mismatch repair genes--detection of microsatellite instability is an important diagnostic criterion. The mono- or dinucleotide repeat DNA sequences are usually amplified from formalin fixed, paraffin embedded tissue by polymerase chain reaction after numerous time consuming steps including deparaffinisation, DNA extraction, and purification. A rapid single step method for direct DNA analysis is described, based on preincubation of paraffin embedded tissue with Triton X-100 followed by DNA amplification with fluorescence labelled primers and electrophoresis in an automated sequencer. This procedure allows precise allele sizing and analysis of genetic instability, is more efficient and time saving, reduces the risk of contamination, and is therefore of particular interest in screening for HNPCC.

p53 autoantibodies in patients with pancreatitis and pancreatic carcinoma.

In human pancreatic carcinoma (PCa) mutations in the p53 tumor suppressor gene are present in up to 50% of cases. Conformational change and cellular accumulation, together with subsequent release of mutant and normal p53 protein from transformed cells, may initiate a B-cell response with generation of circulating autoantibodies to p53 protein (anti-p53). In the present study we analyzed the sera of 85 consecutive patients with acute pancreatitis (N = 19), chronic pancreatitis (N = 33), and PCa (N = 33) to evaluate the specificity of autoantibodies to p53 protein as a serological marker for PCa. Detection of anti-p53 was performed using an enzyme-linked immunosorbent assay system with immobilized recombinant wild-type p53 protein. Autoantibodies to p53 were detectable in 1 of 19 patients with acute (5.3%) and in 4 of 33 patients with chronic pancreatitis (12.1%). All anti-p53-positive patients with acute or chronic pancreatitis were carefully examined and no underlying malignant disease was found. During follow-up (range, 281-647 days; mean, 472 days) none of these patients showed any evidence for subsequent development of PCa or any other malignant disease. In patients with PCa, anti-p53 was detected in 6 of 33 cases, resulting in a sensitivity of 18.2% with a specificity of 90.4%. In contrast to anti-p53, detection of serum carbohydrate antigen (CA 19-9) resulted in a sensitivity and specificity of 69.7 and 71.2% (CA 19-9, > 37 U/ml) and 51.5 and 96.2% (CA 19.9, > 100 U/ml) for the detection of PCa, respectively. Taken together, the sensitivity of anti-p53 formation was low in patients with PCa (18.2%). Furthermore, the detection of anti-p53 was not specific for malignancy, indicating that severe inflammatory processes may also induce anti-p53 formation.

Anti-p53 autoantibodies in hepatitis C virus-infected patients.

Mutations in the p53 gene with generation of circulating autoantibodies to p53 protein (anti-p53) have been recently detected in a significant proportion of patients with different malignant diseases. Using ELISA methods we assessed alpha-fetoprotein (AFP) and anti-p53 as serological screening parameters for hepatocellular carcinoma (HCC) in 147 consecutive patients with hepatitis C virus-related chronic hepatitis. Liver cirrhosis was histologically diagnosed in 58 patients (39,5%) and a HCC confirmed in 7 patients (4.8%). Serum AFP levels were raised above 20 ng/ml in 26/147 patients (17.7%) and above 100 ng/ml in 5/147 patients (3.4%). In 6/7 patients with HCC serum AFP was raised above 20 ng/ml, but only in 3/7 cases above 100 ng/ml. Autoantibodies to p53 protein were detected in 3/7 patients with HCC, but in 0/140 patients without HCC (sensitivity 42.9%, specificity 100%). In conclusion, the presence of anti-p53 was specific for malignancy and independent of AFP status. Overall, the sensitivity of serological screening for HCC in patients with hepatitis C virus-related chronic hepatitis was improved by combining AFP measurements (level > 100 ng/ml) with the detection of anti-p53.

Multidisciplinary treatment of desmoid tumours in Gardner's syndrome due to a large interstitial deletion of chromosome 5q.

BACKGROUND AND AIMS: Classic autosomal-dominant familial adenomatous polyposis (FAP) is clinically defined by the development of hundreds to thousands of colorectal adenomas beginning in childhood and adolescence. A variant of FAP characterized by polyposis in combination with osteomas or soft tissue tumours is called Gardner's syndrome. FAP is caused by germline inactivation of the APC (adenomatous polyposis coli) tumour-suppressor gene located on the long arm of chromosome 5 (5q21-5q22). Cytogenetically visible deletions of chromosome 5q encompassing APC have very rarely been reported. Here, we aimed to phenotypically and genetically characterize a patient with a heterozygous 5q deletion resulting in Gardner's syndrome. METHODS AND RESULTS: A 26-year-old female patient with mild mental handicap and dysmorphic features due to a cytogenetically visible deletion on chromosome 5q (microscopically estimated region 5q14-5q23) presented at our tertiary referral centre because of mild adenomatous polyposis (<500 polyps). Twenty months after prophylactic proctocolectomy with definitive ileostomy, three rapidly growing desmoids were observed. Tumour-associated complications necessitated a multidisciplinary approach including medical treatment, surgery and radiation therapy. The characterization of the deletion by comparative genomic hybridization identified a large 5q deletion expanding over a 20-Mb region (5q21.3-5q23.3) including the APC gene. CONCLUSION: Chromosome deletions must be suspected in patients presenting with FAP together with mental handicap and dysmorphic features. This case also impressively shows that FAP-associated desmoids need multimodal treatment taking into account the patient's individual symptoms, disease progression and tumour location.

Absence of the interstitial cell of Cajal network in mitochondrial neurogastrointestinal encephalomyopathy.

Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is a rare autosomal-recessive multisystemic disorder with predominant gastrointestinal involvement, presenting with variable degrees of gut dysmotility up to frank chronic intestinal pseudoobstruction. Despite major advances in understanding its basic molecular pathogenesis in recent years, the distinct mechanisms and pathoanatomical substrate underlying MNGIE-associated gastrointestinal dysmotility are still widely unknown. As yet, though their critical role in proper gastrointestinal transit in terms of spontaneous pacemaker activity and enteric neurotransmission is well established, the population of the interstitial cells of Cajal (ICC) has not been investigated in MNGIE. Therefore, we examined small bowel samples of a well-characterized MNGIE patient by using conventional histology and immunohistochemistry techniques. The ICC network was studied by immunohistochemistry for the tyrosine kinase Kit (CD117), known to reliably detect ICCs, while mucosal mast cells served as an internal and normal small bowel specimen as external controls. At a light microscopic level, no gross structural alteration of the bowel wall composition and its neuromuscular elements was noted. However, a complete absence of Kit immunoreactive cells could be demonstrated in regions where ICCs are normally abundant, while internal and external controls retained strong Kit positivity. In conclusion, our preliminary results provide a first evidence for an alteration of the ICC network in MNGIE, and support the notion that ICC loss might be an early pathogenetic event in MNGIE-associated gut motor dysfunction before significant myopathic and/or neuropathic structural changes occur.

Characterization of the nuclear import of human MutLalpha.

DNA mismatch repair (MMR) is essential for the maintenance of replication fidelity. Its major task is to recognize mismatches as well as insertion/deletion loops of newly synthesized DNA strands. Although different players of human MMR have been identified, the regulation of essential steps of MMR is poorly understood. Because MMR is initiated in the nucleus, nuclear import might be a mechanism to regulate MMR. Nuclear targeting is accomplished by conserved signal sequences called nuclear localization signals (NLS), which represent clusters of positively charged amino acids (aa). hMLH1 contains two clusters of positively charged amino acids, which are candidate NLS sequences (aa 469-472 and 496-499), while hPMS2 contains one (aa 574-580). To study the effect of these clusters on nuclear import, NLS mutants of hMLH1 and hPMS2 were generated and expressed in 293T cells. The subcellular localization of the mutant constructs was monitored by confocal laser microscopy. We demonstrated that missense mutations of two signal sequences, one in hMLH1 and one in hPMS2, lead to impaired nuclear import, which was especially prominent for mutants of the hMLH1 residues K471 and R472; and hPMS2 residues K577 and R578.

Randomized, double-blind, placebo-controlled trial of interferon alfa2a with and without amantadine as initial treatment for chronic hepatitis C.

Although the antiviral effects of amantadine sulphate (1-aminoadamantan sulphate) have not been characterized for the hepatitis C virus (HCV), previous pilot studies have suggested promising results in patients with chronic hepatitis C. The aim of the present study was to compare the efficacy, safety, and health-related quality of life (HRQOL) of interferon alfa (IFN-alpha) alone or in combination with oral amantadine for treatment of chronic hepatitis C. One hundred nineteen previously untreated patients with chronic hepatitis C were randomly allocated to treatment with IFN-alpha2a at a dose of 6 megaunits 3 times a week subcutaneously for 24 weeks, followed by 3 megaunits thrice weekly for an additional 24 weeks plus amantadine sulphate administered orally 100 mg twice a day for 48 weeks or the same IFN regimen plus a matched placebo. The primary endpoint was undectable serum HCV RNA (<1,000 copies/mL) at week 24 after treatment. At the end of treatment and the 24-week follow-up period serum HCV RNA was undetectable in 20 (34%) and 6 (10%) of the 59 patients treated with the combination IFN-alpha plus amantadine and in 20 (33%) and 13 (22%) of the 60 patients treated with IFN-alpha alone, respectively (P = n.s.). Discontinuation of therapy for adverse events was similar in both treatment groups. Although treatment with IFN-alpha worsened HRQOL, combination with amantadine showed a substantial trend to improve fatigue and vigor. In conclusion, combination therapy IFN-alpha plus amantadine is as effective as IFN-alpha monotherapy in previously untreated patients with chronic hepatitis C.

5'-CpG island methylation of the LKB1/STK11 promoter and allelic loss at chromosome 19p13.3 in sporadic colorectal cancer.

BACKGROUND: In patients with Peutz-Jeghers syndrome (PJS), causative germline mutations in the LKB1/STK11 gene on chromosome 19p13.3 have been identified. Because of the loss of heterozygosity (LOH) at 19p13.3 in hamartomas and the cancer susceptibility of patients with PJS, LKB1/STK11 is suggested to act as a tumour suppressor. However, the frequency of genetic and epigenetic inactivation of LKB1/STK11 in sporadic tumours is unclear. AIMS: To investigate the LKB1/STK11 gene for promoter hypermethylation and allelic loss in tumour specimens of patients with sporadic colorectal cancer. METHODS: DNA from 50 consecutive paraffin embedded sporadic colorectal adenocarcinomas and corresponding normal epithelium was extracted. After bisulphite treatment, specimens were analysed for methylation of the LKB1/STK11 promoter 5'-CpG island by methylation specific polymerase chain reaction (MSP). In addition, tumours were analysed for LOH of chromosome 19p13.3. In tumours exhibiting LOH, LKB1/STK11 was sequenced. RESULTS: MSP was successful in 48 of 50 tumour specimens. Of those, four (8%) demonstrated hypermethylation of the LKB1/STK11 promoter 5'-CpG island. Moreover, LOH at either D19S886 or D19S878 was observed in five of 38 (13%) informative tumours. All five tumours showing LOH at 19p13.3 were advanced and four of five were located in the left sided colon. There was no correlation between LOH and LKB1/STK11 promoter hypermethylation or somatic mutation. CONCLUSIONS: In sporadic colorectal cancer, hypermethylation of the LKB1/STK11 promoter and allelic loss at the STK 11 gene locus are rare events. LOH at 19p13.3 was associated with advanced tumour stage and left sided location but not with LKB1/STK11 promoter hypermethylation or somatic mutation.

Alpha-fetoprotein and p53 autoantibodies in patients with chronic hepatitis C.

Hepatitis C virus infection is a common cause of chronic liver disease and hepatocellular carcinoma. Recently, mutations in the p53 tumor suppressor gene with generation of circulating autoantibodies to p53 protein have been detected in a significant proportion of patients with different malignancies. Using ELISA methods we assessed alpha-fetoprotein and anti-p53 as serological screening parameters for hepatocellular carcinoma in 147 consecutive patients with chronic hepatitis C. Liver cirrhosis was histologically diagnosed in 58 patients (39.5%) and a hepatocellular carcinoma confirmed in seven patients (4.8%). Serum alpha-fetoprotein was raised above 20 ng/ml in 26/147 patients and above 100 ng/ml in 5/147 patients. In 6/7 patients with hepatocellular carcinoma, alpha-fetoprotein was raised above 20 ng/ml, but only in 3/7 cases above 100 ng/ml, resulting in a sensitivity and specificity of 85.7% and 85.7% (alpha-fetoprotein > 20 ng/ml) and 42.9% and 98.6% (alpha-fetoprotein > 100 ng/ml) for the detection of hepatocellular carcinoma, respectively. Autoantibodies to p53 were detected in 3/7 patients with hepatocellular carcinoma, but in 0/140 patients without malignancy (sensitivity 42.9%, specificity 100%). Screening for hepatocellular carcinoma was improved by combining alpha-fetoprotein measurement (level > 100 ng/ml) with detection for anti-p53 (sensitivity 71.4%, specificity 98.6%). In conclusion, the presence of anti-p53 was highly specific for malignancy and independent of alpha-fetoprotein status. Further studies including a larger number of patients with hepatitis C virus-related hepatocellular carcinoma are required to investigate whether serological testing for anti-p53 in combination with alpha-fetoprotein might improve the detection of hepatocellular carcinoma in high-risk patients with liver cirrhosis.

Evaluation of rapid microsatellite analysis of paraffin-embedded specimens in screening for hereditary nonpolyposis colorectal cancer.

Length alterations in short repetitive DNA sequences, termed microsatellite instability (MSI), are used as a diagnostic criterion of replication errors caused by various mutations in at least five mismatch repair genes. Therefore, MSI analysis is useful in clinical practice to identify patients with hereditary nonpolyposis colorectal cancer (HNPCC). MSI can be detected by amplification of microsatellite loci in DNA extracted from paraffin-embedded tumor and corresponding peritumoral specimens after numerous time consuming steps limiting the clinical utilities. Rapid microsatellite analysis, a efficient and rapid DNA extraction technique based on Triton X-100 preincubation, was compared with the conventional DNA extraction for HNPCC screening in colorectal tumor specimens from 12 patients. Five complex and two noncomplex (CA)n microsatellite loci were tested, with use of multicolor fluorescent analysis. MSI and loss of heterozygosity in colorectal tumor samples could equally be assessed with the two DNA preparation methods, whereas the number of initially unsuccessful DNA extractions from paraffin-embedded tissue specimens and overall duration for MSI analysis were significantly reduced when rapid microsatellite analysis was used. A replication error-positive phenotype was detected in 2 of 10 patients with a positive family history for colorectal cancer, and diagnosis of HNPCC was finally confirmed by detection of a specific germline mutation. The described rapid microsatellite analysis is less time consuming and more efficient, and, in general, it reduces the risk of contamination by limiting the number of steps required. Therefore, it might replace current DNA extraction procedures. Furthermore, techniques using fluorescent polymerase chain reaction and semiautomated DNA sequencer allow for precise, observer-independent, and rapid scoring in MSI and loss of heterozygosity assessment. A combination of our rapid DNA extraction method and the use of a highly specific microsatellite marker might improve replication error analysis in HNPCC screening.

Peutz-Jeghers syndrome: molecular analysis of a three-generation kindred with a novel defect in the serine threonine kinase gene STK11.

The Peutz-Jeghers syndrome, phenotypically characterized by mucocutaneous pigmentation and hamartomatous polyposis, is an autosomal dominant disease with variable expression and incomplete penetrance. Moreover, affected patients are at increased risk for gastrointestinal and other malignancies. Recently, a mutated gene encoding abnormal forms of the novel serine threonine kinase STK11 has been identified as a genetic cause of Peutz-Jeghers syndrome. Here, we report the molecular analysis of the STK11 gene in a patient with Peutz-Jeghers syndrome, which in exon 1 revealed a guanine (G) insertion in the 5 G repeat of codons 51-53. The insertion leads to a frameshift with a premature TGA stop codon 324 bp downstream in codon 162, predicting the expression of a truncated protein without kinase activity. This heterozygous germline mutation was also found in the affected father and in one affected sister of the index patient, but not in any phenotypically unaffected family member or in unrelated control subjects. In DNA isolated from microdissected hamartomatous polyps of the index patient, exon 1 of the STK11 gene could not be amplified suggesting that both alleles of STK11 exon 1 were lost in the hamartomatous polyps. Identification of a STK11 gene mutation in an index patient offers the possibility of a predictive diagnosis, and initiation of specific screening programs in the genetically affected kindred.

A de novo deletion of chromosome 5q causing familial adenomatous polyposis, dysmorphic features, and mild mental retardation.

Familial adenomatous polyposis (FAP) is an autosomal dominant disorder that typically presents with colorectal cancer secondary to extensive adenomatous polyps of the colon. The molecular basis and clinical phenotype of FAP are well known. Recurrent episodes of severe abdominal pain and a positive fecal occult blood test in an 18-yr-old boy with mild mental retardation and slight dysmorphic features of the face, head, and skeletal system led to the diagnosis of FAP. The clinical workup revealed the presence of over 100 sessile colonic polyps but no polyp formation in the upper GI tract, no cancer development, nor other FAP-associated lesions. To find out whether there is an association between mental retardation and FAP we performed a chromosome analysis including comparative genomic hybridization and an indirect genotype analysis with polymorphic markers from the APC gene region. Cytogenetic analysis showed an interstitial deletion of chromosomal region 5q that was confined to the region 5q21-q22 by comparative genomic hybridization. The deletion, spanning about 10 centimorgans, encompassed the complete APC gene and can be considered as causative for FAP. Moreover, molecular genetic analysis with polymorphic markers flanking the APC gene demonstrated a de novo deletion on the paternal chromosome. Cytogenetically detectable deletions on chromosome 5 including the APC gene generally lead to an associated gene deletion syndrome. Individuals who present with mild mental retardation and dysmorphic features should therefore be investigated for chromosomal deletions. If the deletion encompasses the APC gene, these patients are at high risk of developing FAP and associated complications.

Transient mismatch repair gene transfection for functional analysis of genetic hMLH1 and hMSH2 variants.

BACKGROUND: Germline mutations in the mismatch repair (MMR) genes hMLH1 and hMSH2 can cause hereditary non-polyposis colorectal cancer (HNPCC). However, the functional in vitro analysis of hMLH1 and hMSH2 mutations remains difficult. AIMS: To establish an in vitro method for the functional characterisation of hMLH1 and hMSH2 mutations. METHODS: hMLH1 and hMSH2 wild type (wt) genes and several mutated subclones were transiently transfected in mismatch repair deficient cell lines (HCT-116 and LOVO). Apoptosis, proliferation, and regulation of mRNA expression and protein expression of interacting proteins were analysed by Hoechst staining, AlamarBlue staining, real time polymerase chain reaction, and western blotting, respectively. RESULTS: The protein expression of hMLH1 and hMSH2 mutants was significantly decreased after transfection compared with wild type transfections. The hMLH1 and hMSH2 interacting proteins hPMS2 and hMSH6 became detectable only after transfection of the respective wild type genes. In parallel, hMSH6 mRNA levels were increased in hMSH2 wt transfected cells. However, hPMS2 mRNA levels were independent of the mutation status of its interacting partner hMLH1, indicating a post-transcriptional regulating pathway. In the hMLH1 deficient HCT-116 cell line apoptosis was not affected by transfection of any mismatch repair gene, whereas complementation of hMSH2 deficiency in LOVO cells increased apoptosis. Conversely, proliferative activity of HCT-116 was decreased by complementation with hMLH1wt and unaffected in hMSH2 deficient LOVO cells. CONCLUSION: These data show that the cellular role of the MMR genes and its mutations are assessable in a simple transient transfection system and show the influence of MMR gene regulation on major cell growth regulating mechanisms. This method is applicable for the functional definition of mutations in hMLH1 and hMSH2 genes observed in patients with suspected HNPCC.

Randomized, placebo-controlled, double-blind trial with interferon-alpha with and without amantadine sulphate in primary interferon-alpha nonresponders with chronic hepatitis C.

In primary interferon-alpha (IFN-alpha) nonresponders with chronic hepatitis C, retreatment with IFN-alpha has only limited efficacy with sustained response rates below 10%. Therefore, the aims of the present study were to compare the efficacy and safety of IFN-alpha alone or in combination with amantadine sulphate in nonresponders to previous IFN-alpha monotherapy. Fifty-five IFN-alpha nonresponders with chronic hepatitis C (mean age: 46.6 years) received IFN-alpha 6 MIU thrice weekly for 24 weeks followed by 3 MIU thrice weekly for additional 24 weeks. Amantadine sulphate (n=26) or a matched placebo (n=29) was given orally twice daily for 48 weeks. Because of a low initial response rate at week 12 (13/55 patients) and a high breakthrough rate (8/13 patients) after IFN-alpha dose reduction in week 24, a virological end-of-treatment response with undetectable serum HCV-RNA (< 1000 copies/mL) was achieved in only five patients (IFN-alpha/amantadine sulphate, one patient; IFN-alpha/placebo, four patients). After 24 weeks follow-up a sustained virological response was observed in only two patients receiving IFN-alpha and placebo. Health-related quality-of-life analysis showed a substantial improvement of the Profile of Mood States (POMS) scale concerning the subscales fatigue (P < 0.05) and vigor (P < 0.05) in patients receiving combined IFN-alpha/amantadine sulphate treatment compared with those treated with IFN-alpha alone. IFN-alpha/amantadine sulphate combination therapy was well tolerated without any serious adverse events. In conclusion, retreatment with IFN-alpha and amantadine sulphate does not increase the low sustained virological response rates of IFN-alpha therapy in primary IFN-alpha nonresponders with chronic hepatitis C, but may lead to a sustained improvement of health-related quality-of-life.