Comparison of JAK2V617F mutation assessment employing different molecular diagnostic techniques

Background

The JAK2^V617F mutation is present in the majority of patients with polycythaemia vera and in approximately half of patients with essential thrombocythaemia and primary myelofibrosis. In this study we compare the results of JAK2^V617F mutation detection using three different molecular techniques in the same group of patients affected by essential thrombocythaemia.

Patients and methods

The JAK2 mutation was investigated with a qualitative method in 115 consecutive outpatients with a diagnosis of essential thrombocythaemia made according to WHO 2001 criteria. In 48/115 (41.7%) the allele burden was also evaluated with two different qualitative methods, of which one was a method developed in-house and the other was a commercially available method.

Results

The JAK2^V617F mutation was detected by the qualitative method in 81/115 (69.6%) of the patients. Among the 48/115 patients in whom all three methods were applied, the qualitative method detected the mutation in 38 (79%). According to the quantitative method developed in-house, the mutation was present in 35/48 (73%) of the patients: of these, 2/35 (5.7%) patients were homozygous for the JAK2^V617F mutation. The commercial quantitative method showed the mutation in 37/48 (77%) patients: of these, 9/37 (18%) patients were homozygous. Three of the 13 patients in whom no mutation was detected by the in-house method were positive for the JAK2^V617F according to the commercial method. In one patient the search for the JAK2^V617F mutation was positive with the in-house method but negative with the commercial kit.

Conclusion

Detection of the JAK2^V617F mutation may depend on the molecular technique used. Considering that detection of this mutation will not only have a diagnostic value, but also a role in treatment given the development of JAK2^V617F pathway inhibiting drugs, indications on a reference molecular diagnostic technique for JAK2^V617F assessment and quantification of its allele burden from a panel of experts are warranted.     

MYBPC3 gene variations in hypertrophic cardiomyopathy patients in India

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is a complex cardiac muscular disorder, inherited as an autosomal dominant disease with variable penetrance. Cardiac myosin-binding protein C (MyBPC) is the predominant myosin-binding protein isoform in the heart muscle. One hundred forty-seven mutations have been detected in MYBPC3, accounting for 15% of all HCM cases.

OBJECTIVE

To screen exons 16, 18, 19, 22, 24, 28, 30, 31 and 34 in the MYBPC3 gene in Indian HCM patients.

METHODS

Sixty control and 95 HCM samples were collected from cardiology units of the CARE Hospital (Nampally, Banjara Hills, Secunderabad, India) for genomic DNA isolation followed by polymerase chain reaction and single-stranded conformational polymorphism analysis.

RESULTS

Screening of the exons revealed two variations – one novel frame shift mutation in exon 19 at the nucleotide position 11577^11578 and one novel single nucleotide polymorphism (SNP) in codon 1093 of exon 31, coding for glycine with a C>T transition (GGC/GGT), in addition to the seven known SNPs mainly in the intronic region and one known missense mutation D770N in this population.

CONCLUSION

The novel frame shift mutation identified in exon 19, D570fs, with the insertion of an adenine residue in codon 570 coding for aspartate, results in a premature termination codon that produces a truncated protein lacking myosin- and titin-binding sites, explaining the role of the nonsense-mediated decay pathway. A novel SNP identified in codon 1093 of exon 31 was found to be a synonymous codon, which may have a regulatory effect at the translational level, attributing to affinity differences between codon-anticodon interactions. The screening of this gene may be relevant in the Indian context.     

Analysis and implications of changing hepatopancreatobiliary (HPB) case loads in general surgery residency training for HPB surgery accreditation

Objective

This study was conducted to determine whether residents are receiving enough hepatopancreatobiliary (HPB) training during general surgery residencies to exclude the necessity of pursuing formal fellowships in HPB surgery.

Methods

Trends in HPB surgery training were examined using Accreditation Council for Graduate Medical Education (ACGME) operative log data for the academic years 1999/2000 to 2009/2010.

Results

Of 800 000 HPB operations performed annually in the USA, the proportion of HPB procedures performed by general surgery residents increased from 15% (122 007) to 18% (143 000) between the periods under study. Numbers of pancreatic, liver and biliary procedures performed by graduating general surgery residents increased by 47% (from 8185 to 12 006), 31% (from 7468 to 9765), and 14% (from 106 354 to 121 239), respectively. The mean number of operations undertaken by a graduating resident increased from 8.3 to 11.5 (38% increase) for pancreatic surgeries, from 7.6 to 9.4 (24% increase) for liver surgeries, and from 107.5 to 116.6 (8% increase) for biliary surgeries. Total numbers of complex pancreatic, liver and biliary procedures increased by 91% (from 4768 to 9129) and 24% (from 6649 to 8233), and decreased by 29% (from 6581 to 4648), respectively.

Conclusions

The overall trend shows an increase in the number of HPB procedures undertaken by graduating general surgery residents. The mean number of procedures exceeds ACGME requirements, but falls short of association guidelines. However, certain residents exceed International Hepato-Pancreato-Biliary Association (IHPBA) fellowship requirements for total and complex procedures during residency. Consideration should be given to those residents to allow them to bypass fellowship training provided that they meet other IHPBA standards.     

New fibrillin gene mutation - possible cause of ascending aortic dilation in patients with aortic valve disease: Preliminary results

BACKGROUND:

Approximately 10% of patients who undergo surgery for aortic valve disease (stenosis or regurgitation) suffer from ascending aortic dilation (AAD). A possible genetic etiology of AAD associated with aortic valve disease has been repeatedly mentioned in the literature, but a specific responsible gene mutation has not been described.

METHODS:

In the present study, two groups of patients were compared, all of whom underwent surgery for aortic valve disease. Group A was a cohort of 27 patients who suffered from aortic valve disease associated with AAD. Group B was a cohort of 29 patients with structural aortic valve disease, but without concomitant AAD (control group). Genomic DNA was extracted from the white blood cells of peripheral blood samples and was amplified using primers specific for chosen exons of the fibrillin-1 gene, including their intron/exon boundaries. Exons 26 and 27 were selected for analysis.

RESULTS:

Analysis of the intronic part situated close to exon 27 showed insertion of cytosine between nucleotide 37 682 and 37 683 of query sequence. This insertions was classified as IVS 37 682 and 37 683insC. This mutation was found in all 27 patients from group A (patients with structural aortic valve disease accompanied by significant AAD). The abovementioned mutation was not found in any of the 29 patients from group B.

CONCLUSIONS:

This finding has potential implications for risk stratification and therapeutic targeting not only for patients with existing disease, but also for the general population. Future studies are needed to determine the clinical utility of the finding; however, the present hypothesis needs to be verified by further molecular studies.     

G1896A Precore Mutation and Association With HBeAg Status,Genotype and Clinical Status in Patients With Chronic Hepatitis B

Background:

Precore stop codon (G1896A) mutation is one of the commonest mutations found in patients with chronic hepatitis B. However, over the years, this mutation was not reported much in Malaysia.

Objectives:

We therefore investigated the presence of G1896A mutation in Malaysian population and its association with HBeAg status, clinical stage, hepatitis B virus (HBV) genotype and e-seroconversion rate.

Patients and Methods:

Serum samples from 93 patients confirmed as hepatitis B carriers were collected for molecular assay. The whole genome of HBV was amplified by polymerase chain reaction and directly sequenced. The precore and basal core promoter regions were analyzed for presence of mutations.

Results:

The most commonly observed mutation in the precore region was C1858T with 64.5% prevalence. The precore mutation of interest (G1896A) was identified in 25.8% of isolates. The basal core promoter mutations detected were A1762T-G1764A (26.9%), C1653T (8.6%), A1752G (10.8%) and C1766T (2.2%). No significant association was observed between G1896A mutation and HBeAg-negativity. Nonetheless, G1896A was highly prevalent among HBV genotype B. Clinical association revealed that subjects with G1896A mutations were mainly detected in asymptomatic chronic hepatitis B (58.3%) and liver cirrhosis (41.7%). One subject was diagnosed with fulminant hepatitis (4.2%) and 8.3% had hepatocellular carcinoma (HCC).

Conclusions:

Our data suggested an intermediate prevalence of G1896A mutation among Malaysian hepatitis B carriers. The stop codon mutation has a significant association with genotype B and patients with chronic hepatitis B and liver cirrhosis.     

Detection of rearrangement of anaplastic lymphoma kinase (ALK) and mutation of epidermal growth factor receptor (EGFR) in primary pulmonary lymphoepithelioma-like carcinoma

Background

Primary pulmonary lymphoepithelioma-like carcinoma (LELC) is a distinct rare subtype of lung cancer. The prevalence of anaplastic lymphoma kinase (ALK) rearrangement and epidermal growth factor receptor (EGFR) mutation in primary pulmonary LELC had not been thoroughly investigated.

Methods

We investigated a cohort of 42 patients with primary pulmonary LELC and genotyped for ALK rearrangement and EGFR mutation. ALK rearrangement was detected by fluorescence in situ hybridization (FISH). EGFR mutational analysis of exons 18 through 21 was analyzed by TaqMan real-time polymerase chain reaction (PCR).

Results

Epstein-Barr virus-encoded RNAs (EBERs) showed positive signals in all 42 patients. By immunohistochemistry staining, all patients demonstrated positive expression of CK5/6 and P63, but almost all patients were negative for TTF-1 (34/34, 100%) or CK7 (34/35, 97.1%). None of the 42 patients had ALK rearrangement. Of 42 patients tested, only one patient (2.4%) harbored L858R mutation and gefitinib was applied to this case, however no objective response was observed and the progression free survival (PFS) time was only 1 month.

Conclusions

Primary pulmonary LELC is a unique histological subtype of lung cancer. ALK rearrangement and EGFR mutation are lack and they may not be the oncogenic driver gene in pulmonary LELC. Future efforts should be made to explore other oncogenic driver gene to guide targeted therapy in this rare disease to determine the optimal treatment.

Keywords

Pulmonary lymphoepithelioma-like carcinoma (LELC); anaplastic lymphoma kinase (ALK); epidermal growth factor receptor (EGFR); targeted therapy; Epstein-Barr virus (EBV)     

Incorporating an HPB fellowship does not diminish surgical residents' HPB experience in a high-volume training centre

Background:

Surgical residency training is evolving, and trainees who wish to practice hepato-pancreato-biliary (HPB) surgery in the future will be required to obtain advanced training. As this paradigm evolves, it is crucial that HPB fellowship incorporation into an established surgical residency programme does not diminish surgical residents'' exposure to complex HPB procedures. We hypothesized that incorporation of a HPB fellowship in a high-volume clinical training programme would not detract from residents'' HPB experience.

Methods:

Resident operative case logs and HPB fellow case logs were reviewed. Resident exposure to complex HPB procedures for 3 years prior to and 3 years after fellowship incorporation were compared.

Results:

No significant changes in surgical resident exposure to liver and pancreatic resection were seen between the two time periods. Surgical resident exposure to complex biliary procedures decreased in the 3 years after HPB fellowship incorporation (P= 0.003); however, exceeded the national average in each year except 2006. Graduating residents'' overall HPB experience was unchanged in the 3 years prior to and after incorporating an HPB fellow. Expansion of HPB volume was a critical part of successful HPB fellowship implementation.

Discussion:

An HPB fellowship programme can be incorporated into a high-volume clinical training programme without detracting from resident HPB experience. Individual training programmes should carefully assess their capability to provide an adequate clinical experience for fellows without diminishing resident exposure to complex HPB procedures.     

Impact of EGFR mutation status on tumor response and progression free survival after first-line chemotherapy in patients with advanced non-small-cell lung cancer: a meta-analysis

Objectives

Non-small-cell lung cancer (NSCLC) patients harboring sensitive epidermal growth factor receptor (EGFR) mutations derive greater benefits from EGFR-tyrosine kinase inhibitors (EGFR-TKIs) than those with wild type tumors. However, whether EGFR mutation status is associated with the efficacy of cytotoxic chemotherapy or prognosis in advanced NSCLC patients remained controversial. Thus, we sought to conduct a meta-analysis to answer this question.

Methods

Electronic databases were searched for eligible literatures. The primary outcomes were objective response rate (ORR) and 6-month progression-free survival (PFS) rate. The pooled odds ratio (OR) was calculated using random-effects model. Subgroup analyses stratified by study types, EGFR mutation detection methods, chemotherapy regimens, and patient origins were proposed.

Results

A total of 14 studies involving 1,772 advanced NSCLC patients with known EGFR mutation status who had received first-line chemotherapy were included. Patients with positive EGFR mutation had numerically higher ORR than wild type patients (36.2% vs. 30.1%) without significant differences (OR 1.24, 95% CI, 0.90 to 1.70; P=0.19). However, patients with EGFR mutants had significantly superior 6-month PFS rate than wild-type patients (58.6% vs. 47.2%; OR 1.88, 95% CI, 1.33 to 2.65; P=0.0003). Results of the subgroup analyses were concordant with the overall ones.

Conclusions

This comprehensive analysis revealed that advanced NSCLC patients with sensitivity EGFR mutation had higher 6-month PFS rate and potentially greater ORR compared with wild-type patients after first-line chemotherapy. It suggested that EGFR mutation status should be considered a significant factor for patient stratification in evaluating the efficacy of antitumor agents in addition to EGFR-TKIs.     

Portal vein arterialization: a salvage procedure for a totally de-arterialized liver. The Paul Brousse Hospital experience

Background

Portal vein arterialization (PVA) has been used as a salvage inflow technique when hepatic artery (HA) reconstruction is deemed impossible in liver transplantation (LT) or hepatopancreatobiliary (HPB) surgery. Outcomes and the management of possible complications have not been well described.

Methods

The present study analysed outcomes in 16 patients who underwent PVA during the period from February 2005 to January 2011 for HA thrombosis post-LT (n = 7) or after liver resection (n = 1), during curative resection for locally advanced HPB cancers (requiring HA interruption) (n = 7) and for HA resection without reconstruction (n = 1). In addition, a literature review was conducted.

Results

Nine patients were women. The median age of the patients was 58 years (range: 30–72 years). Recovery of intrahepatic arterial signals and PVA shunt patency were documented using Doppler ultrasound until the last follow-up (or until shunt thrombosis in some cases). Of five postoperative deaths, two occurred as a result of haemorrhagic shock, one as a result of liver ischaemia and one as a result of sepsis. The fifth patient died at home of unknown cause. Three patients (19%) had major bleeding related to portal hypertension (PHT). Of these, two underwent re-exploration and one underwent successful shunt embolization to control the bleeding. Four patients (25%) had early shunt thrombosis, two of whom underwent a second PVA. After a median follow-up of 13 months (range: 1–60 months), 10 patients (63%) remained alive with normal liver function and one submitted to retransplantation.

Conclusions

Portal vein arterialization results in acceptable rates of survival in relation to spontaneous outcomes in patients with completely de-arterialized livers. The management of complications (especially PHT) after the procedure is challenging. Portal vein arterialization may represent a salvage option or a bridge to liver retransplantation and thus may make curative resection in locally advanced HPB cancers with vascular involvement feasible.     

Clinical features and mutation status of EGFR,KRAS, BRAF,EML4-ALK and ROS1 between surgical resection samples and non surgical resection samples in lung cancer

Background

Target therapy is the first-line treatment in lung cancer. The testing of driver gene mutations is crucial for decision of treatment. Many lung cancer patients are in advanced grade, and lose the chance of operation.

Methods

The tissue used to perform mutation testing is only from biopsy. In order to analysis the difference between surgical resection samples (SRSs) and non-surgical resection samples (NSRSs), 1,357 surgical tissues and 145 biopsy samples histopathologically diagnosed with lung cancer were collected to detect the mutation status of EGFR, KRAS, BRAF, EML4-ALK and ROS1 in this study.

Results

There were no significant differences of age, gender, and histological type between the two group patients we collected; however, the significant difference was present in grade. More early stage patients were in the surgical group, but more advanced stage lung cancer patients were in non surgical group. In the mutation analysis, we also found no significant differences in all driver genes we detected between the two groups.

Conclusions

Both surgical resection samples and biopsy samples could be used to perform the testing the driver gene mutation.     

The role of heart-type fatty acid-binding protein in the diagnosis of acute coronary syndrome

BACKGROUND:

Heart-type fatty acid-binding protein (H-FABP) is a membrane-bound protein that facilitates transport of fatty acids from the blood into the heart. It is currently being used outside the United States for the early diagnosis of myocardial infarction (MI). However, previous studies have shown inconsistent correlation of H-FABP with standard cardiac biomarkers.

METHODS:

Fifty patients admitted with ST segment elevation MI (n=25), non-ST segment elevation MI (n=15) or unstable angina (n=10) were evaluated. The CardioDetect med cardiac infarction test (rennesens GmbH, Germany) was used to measure both qualitative and quantitative H-FABP.

RESULTS:

Of the 40 patients with acute MI, the initial troponin assay was positive in 35 patients (88%), the qualitative H-FABP assay was positive in 23 patients (58%) and the quantitative H-FABP assay was positive in 15 patients (38%) (P=0.001). No patient with MI had a positive H-FABP assay with a negative initial troponin assay.

CONCLUSION:

In the present study, the results of both the qualitative and quantitative H-FABP assays neither appeared earlier nor provided increased sensitivity compared with troponin in diagnosing acute MI. Accordingly, the use of H-FABP as a diagnostic tool for MI is limited.     

Evidence for a founder effect of the MPL-S505N mutation in eight Italian pedigrees with hereditary thrombocythemia

Background

Hereditary thrombocythemia is a rare disease characterized by increased megakaryopoiesis and overproduction of platelets. Germ line mutations have been identified in the genes for thrombopoietin (THPO) and its receptor, MPL. A clustering of familial cases with the MPL-G1073A mutation that results in a serine to asparagine substitution (S505N) has been recently reported in Italy. Here we performed haplotype analysis in nine families (eight Italian and one Japanese) with hereditary thrombocythemia carrying the MPL-S505N mutation in the MPL gene.

Design and Methods

The MPL gene was examined by genomic DNA sequencing. Haplotype analysis was performed using microsatellites and single nucleotide polymorphisms.

Results

Analysis of microsatellite markers and single nucleotide polymorphisms in the eight Italian families with hereditary thrombocythemia revealed the presence of a common haplotype compatible with a founder effect, which may have originated 23 generations ago. This haplotype was rarely observed in 132 unrelated individuals and was absent in a Japanese family with the MPL-S505N mutation.

Conclusions

The recurrent MPL-S505N mutation found in the eight Italian families with hereditary thrombocythemia is likely due to a founder effect.     

The utility of Xenon-133 liver scan in the diagnosis and management of nonalcoholic fatty liver disease

BACKGROUND:

Nonalcoholic fatty liver disease (NAFLD) is an important and common condition affecting approximately 20% of the general population. Given the limitation of radiological investigations, diagnosis often requires a liver biopsy.

OBJECTIVE:

To compare Xenon-133 (Xe-133) liver scanning with ultrasonography in the diagnosis of NAFLD.

METHODS:

From January 2003 to February 2007, 258 consecutive patients with suspected NAFLD underwent Xe-133 liver scanning at Royal Victoria Hospital (Montreal, Quebec). Of these, 43 patients underwent ultrasonography and liver biopsy for the evaluation of NAFLD. Patients with other liver diseases and significant alcohol consumption were excluded. Two nuclear medicine physicians assessed liver Xe-133 uptake and measured the grade of steatosis using a standardized protocol. The degree of steatosis was determined from biopsy specimens assessed by two hepatopathologists.

RESULTS:

NAFLD was identified by liver biopsy in 35 of 43 patients (81.4%). Xe-133 scan demonstrated 94.3% sensitivity (95% CI 81.4% to 98.4%) and 87.5% specificity (95% CI 52.9% to 99.4%) for the presence of NAFLD. The positive and negative predictive values for detection of steatosis by Xe-133 scan were 97.1% (95% CI 85.1% to 99.8%) and 77.8% (95% CI 45.3% to 93.7%), respectively. The positive and negative likelihood ratios were 7.54 (95% CI 1.20 to 47.26) and 0.07 (95% CI 0.02 to 0.26), respectively. Two patients with NAFLD (5.7%) who had a negative Xe-133 scan result had histologically mild steatosis (<10%). The grade of steatosis on liver biopsy was highly correlated with the results of the Xe-133 scan (r=0.87; P<0.001). The sensitivity and specificity of ultrasound in diagnosing steatosis were 62.9% and 75%, respectively.

CONCLUSION:

Xe-133 liver scan proved to be a safe, reliable, non-invasive method for diagnosing and quantifying hepatic steatosis, and was superior to ultrasound.     

Prevalence of Occult Hepatitis B Virus in Plasma and Peripheral Blood Mononuclear Cell Compartments of Patients With Chronic Hepatitis C Infection in Tehran-Iran

Background

Occult hepatitis B virus (HBV) infection (OBI) is frequently reported in patients with chronic hepatitis C virus (HCV) infection. An association between OBI and more liver damage, cirrhosis, hepatocellular carcinoma, and reduced response to interferon therapy in patients with HCV infection is suggested.

Objectives

The aim of this study was to determine the prevalence of occult HBV, and evaluate its clinical influence on patients with chronic HCV.

Patients and Methods

A cohort study including50 patients with positive results for HCV, and negative results for HBsAg tests was performed. The patients were divided into two groups: one group had positive results for both HCV and occult HBV tests (n = 18), and the other had positive results for HCV, but negative findings for occult HBV (n = 32). All were treated with PEG-IFN alpha-2a and Ribavirin. Presence of HCV RNA was followed in these patients.

Results

HBV-DNA was detected using nested-PCR in 20% of plasma and 32.6% of peripheral blood mononuclear cell (PBMC) compartments. No significant differences were observed between patients with and without occult HBV for sex, age, duration of HCV infection, histological markers, presence of anti-HBc, HCV viral load, and HCV genotype. The response rate was significantly higher in patients with positive results for HBV-DNA test compared to those with negative findings (100% vs. 71.9 %, P < 0.05).

Conclusions

In conclusion, occult HBV was found in 36% of patients with negative results for HBsAg, but positive results for HCV. Detection of HBV-DNA in both PBMCs and plasma together in comparison with plasma alone provided more true identification of OBI.The SVR rate was significantly higher in coinfected patients than mono-infected ones.     

Screening of HHEX Mutations in Chinese Children with Thyroid Dysgenesis

Objective:

Congenital hypothyroidism (CH) is a frequent neonatal endocrine disease with an incidence of about 1:2500 worldwide. Although thyroid dysgenesis (TD) is the most frequent cause of CH cases, its pathogenesis remains unclear. The aim of this study was to screen the hematopoietically-expressedhomeobox gene (HHEX) mutations in Chinese children with TD.

Methods:

Genomic deoxyribonucleic acid was extracted from peripheral blood leukocytes in 234 TD patients from Shandong Province. Mutations in all exons and nearby introns of HHEX were analyzed by direct sequencing after polymerase chain reaction amplification.

Results:

Sequencing analysis of HHEX indicated that no causative mutations were present in the coding regionof the TD patients. However, a genetic variant (IVS2+ 127 G/T, 10.26%) was observed in the intron 2 in HHEX.

Conclusion:

Our results indicate that the frequency of HHEX mutation is very low and may not be the main causative factor in Chinese TD patients. However, these results need to be replicated using larger datasets collected from different populations.     

The R563Q mutation of the epithelial sodium channel beta-subunit is associated with hypertension

Background

A high prevalence of the R563Q mutation of the epithelial sodium channel β-subunit has been reported in South African hypertensives compared with unrelated normotensive controls. To delineate the effects of this mutation against a more uniform genetic background, this study investigated the association of the mutation with hypertension within affected kindreds.

Methods

Forty-five index patients and members of their kindreds were studied. Blood pressure, serum potassium and the presence of the R563Q mutation were determined.

Results

Of the 136 individuals studied, 89 were heterozygous for the R563Q mutation and 47 homozygous RR. The mean arterial pressure was significantly higher in the R563Q heterozygous group (p = 0.005) after adjusting for gender, race, age and kindred membership. Of the R563Q heterozygous subjects, 71 (80%) had hypertension, while 17 (36%) of the R563Q homozygous RR subjects were hypertensive. Six R563Q heterozygous subjects had hypokalaemia and one R563Q homozygous RR subject had hypokalaemia, but the difference was not statistically significant. Two heterozygous patients had Liddle’s syndrome, both occurring during pregnancy.

Conclusion

The R563Q mutation of β-ENaC is associated with hypertension within affected kindreds, but does not usually cause the full Liddle’s syndrome phenotype.     

Characterization and Prognostic Value of Mutations in Exons 5 and 6 of the p53 Gene in Patients with Colorectal Cancers in Central Iran

Background/Aims

We aimed to investigate the relation-ships among various mutations of the p53 gene and their protein products, histological characteristics, and disease prognosis of primary colorectal cancer in Isfahan, central Iran.

Methods

Sixty-one patients with colorectal adenocarcinoma were enrolled in the study. Mutations of the p53 gene were detected by single-stranded conformation polymorphism and DNA sequencing. The protein stability was evaluated by immunohistochemistry. Patients were followed up to 48 months.

Results

Twenty-one point mutations in exons 5 and 6 were detected in the tumor specimens of 14 patients (23%). Of those, 81% and 9.5% were missense and nonsense mutations, respectively. There were also two novel mutations in the intronic region between exons 5 and 6. In 11 mutated specimens, protein stability and protein accumulation were identified. There was a relationship between the type of mutation and protein accumulation in exons 5 and 6 of the p53 gene. The presence of the mutation was associated with an advanced stage of cancer (trend, p<0.009). Patients with mutated p53 genes had significantly lower survival rates than those with wild type p53 genes (p<0.01).

Conclusions

Mutations in exons 5 and 6 of the p53 gene are common genetic alterations in colorectal adenocarcinoma in central Iran and are associated with a poor prognosis of the disease.