Comprehensive analysis of gene mutations and mismatch repair in Chinese colorectal cancer patients

BACKGROUND RAS,BRAF,and mismatch repair(MMR)/microsatellite instability(MSI)are crucial biomarkers recommended by clinical practice guidelines for colorectal cancer(CRC).However,their characteristics and influencing factors in Chinese patients have not been thoroughly described.AIM To analyze the clinicopathological features of KRAS,NRAS,BRAF,and PIK3CA mutations and the DNA MMR status in CRC.METHODS We enrolled 2271 Chinese CRC patients at the China-Japan Friendship Hospital.MMR proteins were tested using immunohistochemical analysis,and the KRAS/NRAS/BRAF/PIK3CA mutations were determined using quantitative polymerase chain reaction.Microsatellite status was determined using an MSI detection kit.Statistical analyses were conducted using SPSS software and logistic regression.RESULTS The KRAS,NRAS,BRAF,and PIK3CA mutations were detected in 44.6%,3.4%,3.7%,and 3.9% of CRC patients,respectively.KRAS mutations were more likely to occur in patients with moderate-to-high differentiation.BRAF mutations were more likely to occur in patients with right-sided CRC,poorly differentiated,or no perineural invasion.Deficient MMR(dMMR)was detected in 7.9% of all patients and 16.8% of those with mucinous adenocarcinomas.KRAS,NRAS,BRAF,and PIK3CA mutations were detected in 29.6%,1.1%,8.1%,and 22.3% of patients with dMMR,respectively.The dMMR was more likely to occur in patients with a family history of CRC,aged<50 years,right-sided CRC,poorly differentiated histology,no perineural invasion,and with carcinoma in situ,stage I,or stage II tumors.CONCLUSION This study analyzed the molecular profiles of KRAS,NRAS,BRAF,PIK3CA,and MMR/MSI in CRC,identifying key influencing factors,with implications for clinical management of CRC.

Analysis of an adult diabetes mellitus caused by a rare mutation of the gene:A case report

BACKGROUND This study presents the clinical and genetic mutation characteristics of an unusual case of adult-onset diabetes mellitus occurring in adolescence,featuring a unique mutation in the peroxisome proliferator-activated receptor gamma(PPARG)gene.Data Access Statement:Research data supporting this publication are available from the NN repository at www.NNN.org/download/.CASE SUMMARY The methodology employed entailed meticulous collection of comprehensive clinical data from the probands and their respective family members.Additionally,high-throughput sequencing was conducted to analyze the PPARG genes of the patient,her siblings,and their offspring.The results of this investigation revealed that the patient initially exhibited elevated blood glucose levels during pregnancy,accompanied by insulin resistance and hypertriglyceridemia.Furthermore,these strains displayed increased susceptibility to diabetic kidney disease without any discernible aggregation patterns.The results from the gene detection process demonstrated a heterozygous mutation of guanine(G)at position 284 in the coding region of exon 2 of PPARG,which replaced the base adenine(A)(exon2c.284A>Gp.Tyr95Cys).This missense mutation resulted in the substitution of tyrosine with cysteine at the 95th position of the translated protein.Notably,both of her siblings harbored a nucleotide heterozygous variation at the same site,and both were diagnosed with diabetes.CONCLUSION The PPARG gene mutation,particularly the p.Tyr95Cys mutation,may represent a newly identified subtype of maturity-onset diabetes of the young.This subtype is characterized by insulin resistance and lipid metabolism disorders.

Assessment of pathogenicity and functional characterization of APPL1 gene mutations in diabetic patients

BACKGROUND Adaptor protein,phosphotyrosine interacting with PH domain and leucine zipper 1(APPL1)plays a crucial role in regulating insulin signaling and glucose metabolism.Mutations in the APPL1 gene have been associated with the development of maturity-onset diabetes of the young type 14(MODY14).Currently,only two mutations[c.1655T>A(p.Leu552*)and c.281G>A p.(Asp94Asn)]have been identified in association with this disease.Given the limited understanding of MODY14,it is imperative to identify additional cases and carry out comprehensive research on MODY14 and APPL1 mutations.AIM To assess the pathogenicity of APPL1 gene mutations in diabetic patients and to characterize the functional role of the APPL1 domain.METHODS Patients exhibiting clinical signs and a medical history suggestive of MODY were screened for the study.Whole exome sequencing was performed on the patients as well as their family members.The pathogenicity of the identified APPL1 variants was predicted on the basis of bioinformatics analysis.In addition,the pathogenicity of the novel APPL1 variant was preliminarily evaluated through in vitro functional experiments.Finally,the impact of these variants on APPL1 protein expression and the insulin pathway were assessed,and the potential mechanism underlying the interaction between the APPL1 protein and the insulin receptor was further explored.RESULTS A total of five novel mutations were identified,including four missense mutations(Asp632Tyr,Arg633His,Arg532Gln,and Ile642Met)and one intronic mutation(1153-16A>T).Pathogenicity prediction analysis revealed that the Arg532Gln was pathogenic across all predictions.The Asp632Tyr and Arg633His variants also had pathogenicity based on MutationTaster.In addition,multiple alignment of amino acid sequences showed that the Arg532Gln,Asp632Tyr,and Arg633His variants were conserved across different species.Moreover,in in vitro functional experiments,both the c.1894G>T(at Asp632Tyr)and c.1595G>A(at Arg532Gln)mutations were found to downregulate the expression of APPL1 on both protein and mRNA levels,indicating their pathogenic nature.Therefore,based on the patient’s clinical and family history,combined with the results from bioinformatics analysis and functional experiment,the c.1894G>T(at Asp632Tyr)and c.1595G>A(at Arg532Gln)mutations were classified as pathogenic mutations.Importantly,all these mutations were located within the phosphotyrosinebinding domain of APPL1,which plays a critical role in the insulin sensitization effect.CONCLUSION This study provided new insights into the pathogenicity of APPL1 gene mutations in diabetes and revealed a potential target for the diagnosis and treatment of the disease.

Mutation Characteristics of inhA and katG Genes in Isoniazid-Resistant Mycobacterium Tuberculosis Patients in Xinjiang

Objective:To analyze the mutation characteristics of inhA and katG genes in isoniazid-resistant Mycobacterium tuberculosis in Xinjiang.Methods:The katG and inhA in 148 strains of isoniazid-resistant Mycobacterium tuberculosis were amplified through fluorescence quantitative PCR,and the amplified products were sequenced and compared.Results:The inhA gene mutation rate of 148 strains of isoniazid-resistant mycobacterium tuberculosis was 13.51%(20/148),among which the inhA gene mutation rate among patients of Han,Uygur,and Kazakh ethnicity were 15.87%,13.21%,and 17.65%,respectively.There was no significant difference in the inhA mutation rate among nationalities(c^(2)=2.897,P>0.05).The mutation rate of the katG gene was 84.46%(125/148),among which the mutation rates of patients of Han,Uyghur,and Kazak ethnicities were 82.54%,84.91%,and 76.47%,respectively.The Hui and other ethnic groups were all affected by the katG gene mutation.There was no significant difference in the mutation rate of the katG gene among different ethnicities(c^(2)=3.772,P>0.05).The mutation rates of the inhA gene in southern Xinjiang,northern Xinjiang,and other provinces were 18.60%,9.28%,and 37.50%,respectively.The mutation rates of the inhA gene in different regions were statistically different(c^(2)=6.381,P<0.05).There was no significant difference in the inhA mutation rate between patients from southern and northern Xinjiang(c^(2)=2.214,P>0.05)and between southern Xinjiang and other provinces(c^(2)=1.424,P>0.05).However,the mutation rate of the inhA gene in patients from other provinces was higher than that in northern Xinjiang(c^(2)=5.539,P<0.05).The mutation rates of the katG gene in southern Xinjiang,northern Xinjiang,and other provinces were 81.40%,87.63%,and 62.50%,respectively.There was no significant difference in the mutation rates of the katG gene among different regions(c^(2)=3.989,P>0.05).Conclusion:katG gene mutation was predominant in isoniazid-resistant tuberculosis patients in Xinjiang Uygur Autonomous Region,and inhA and katG gene mutation were no different among different ethnic groups.

Co-existing squamous cell carcinoma and chronic myelomonocytic leukemia with ASXL1 and EZH2 gene mutations:A case report

BACKGROUND Chronic myelomonocytic leukemia(CMML),a rare clonal hematopoietic stem cell disorder characterized by myelodysplastic syndrome and myeloproliferative neoplasms,has a generally poor prognosis,and easily progresses to acute myeloid leukemia.The simultaneous incidence of hematologic malignancies and solid tumors is extremely low,and CMML coinciding with lung malignancies is even rarer.Here,we report a case of CMML,with ASXL1 and EZH2 gene mutations,combined with non-small cell lung cancer(lung squamous cell carcinoma).CASE SUMMARY A 63-year-old male,suffering from toothache accompanied by coughing,sputum,and bloody sputum for three months,was given a blood test after experiencing continuous bleeding resulting from a tooth extraction at a local hospital.Based on morphological results,the patient was diagnosed with CMML and bronchoscopy was performed in situ to confirm the diagnosis of squamous cell carcinoma in the lower lobe of the lung.After receiving azacitidine,programmed cell death protein 1,and platinum-based chemotherapy drugs,the patient developed severe myelosuppression and eventually fatal leukocyte stasis and dyspnea.CONCLUSION During the treatment and observation of CMML and be vigilant of the growth of multiple primary malignant tumors.

Clinical manifestations of adult hereditary spherocytosis with novel SPTB gene mutations and hyperjaundice:A case report

BACKGROUND The aim of the present study was to enhance understanding of the diagnosis and treatment of atypical hereditary spherocytosis(HS),and to broaden the diagnostic thoughts of physicians for patients with jaundice.CASE SUMMARY A 28-year-old male presented with jaundice,bile duct stone,and splenomegaly,but without anemia.Other causes of jaundice were excluded,and gene se-quencing revealed a novel heterozygous variant of c.1801C>T(p.Q601X)in exon 14 of the SPTB(NM_01355436)gene on chromosome 14(chr14:65260580)in the patient’s blood;the biological parents and child of the patient did not have similar variants.A splenectomy was performed on the patient and his bilirubin levels returned to normal after surgery.Thus,a novel gene variant causing HS was identified.This variant may result in the truncation ofβ-hemoglobin in the erythrocyte membrane,leading to loss of normal function,jaundice,and hemolytic anemia.The clinical manifestations of the patient were hyperjaundice and an absence of typical hemolysis during the course of the disease,which caused challenges for diagnosis by the clinicians.CONCLUSION Following a definitive diagnosis,genetic testing and response to treatment identified a gene variant site for a novel hemolytic anemia.

Novel gene mutation in maturity-onset diabetes of the young:A case report

BACKGROUND Maturity-onset diabetes of the young(MODY)is the most common monogenic type of diabetes.Recently,14 gene mutations have been found to be associated with MODY.In addition,the KLF11 gene mutation is the pathogenic gene of MODY7.To date,the clinical and functional characteristics of the novel KLF11mutation c.G31A have not yet been reported.CASE SUMMARY We report of a 30-year-old male patient with a one-year history of nonketosisprone diabetes and a 3-generation family history of diabetes.The patient was found to carry a KLF11 gene mutation.Therefore,the clinical data of family members were collected and investigated.A total of four members of the family were found to have heterozygous mutations in the KLF11 gene c.G31A,which resulted in a change in the corresponding amino acid p.D11N.Three patients had diabetes mellitus,and one patient had impaired glucose tolerance.CONCLUSION The heterozygous mutation of the KLF11 gene c.G31A(p.D11N)is a new mutation site of MODY7.Subsequently,the main treatment included dietary interventions and oral drugs.

ADAMTS3 and FLT4 gene mutations result in congenital lymphangiectasia in newborns:A case report

BACKGROUND Congenital lymphangiectasia is a rare disease characterized by dilated interstitial lymphatic vessels and cystic expansion of the lymphatic vessels.Congenital lymphangiectasia can affect various organ systems;however,it frequently occurs in the lungs accompanied with unexplained pleural effusion.Further,it might not be diagnosed during prenatal examination owing to the absence of pronounced abnormalities.However,after birth the newborn rapidly develops respiratory distress that quickly deteriorates.Genetic variations in proteins controlling the development of lymphatic vessels contribute to the pathophysiology of this disease.We report a rare case of heterozygous mutation of ADAMTS3 and FLT4 genes,which have not been reported previously.CASE SUMMARY We analysed the case of a neonate who had presented with only pleural effusion at a late gestational age and eventually died due to its inability to establish spontaneous breathing after birth.An autopsy revealed lymphangiectasia of the organ systems.Further,whole exome sequencing revealed heterozygous mutations of the lymphangiogenesis-controlling genes,ADAMTS3 and FLT4,and Sanger verification revealed similar lesions in the mother with no symptoms.CONCLUSION Considering the presented case,obstetricians should observe unexplained foetal pleural effusion,and perform pathology analysis and whole exome sequencing for a conclusive diagnosis and prompt treatment.

Analysis of EGFR gene mutations in lung adenocarcinoma in Karamay,Xinjiang,China

Background:To investigate the mutation types and mutation rate of the epidermal growth factor receptor(EGFR)gene in patients with lung adenocarcinoma and the clinical features of lung adenocarcinoma with EGFR gene mutations in Karamay,Xinjiang,China.Methods:Paraffin-embedded tissue samples of adenocarcinoma patients were collected in the Karamay Central Hospital from March 2016 to June 2019,and mutations in exon 18–21 of the EGFR gene were detected by the allele-specific amplification polymerase chain reaction(Amplification RefractoryMutation System–PCR)method.The relationships between themutation types,mutation incidence,and clinical features were analyzed.Results:Of the 170 patients with lung adenocarcinoma,83 had EGFR mutations.The total mutation rate of EGFR in patients with lung adenocarcinoma was 48.8%,which included mutations in exons 18(1.2%[2/170]),19(19.4%[33/170]),20(2.4%[4/170]),and 21(20.6%[35/170]).Intriguingly,there was a case with 9 mutations in exons 20 and 21.The mutations in exon 19 of EGFR resulted in the deletion of codons 746 to 750.The main mutation in exon 21 was L858R(91.4%[32/35]).There was no significant difference in exons 19 and 21 mutation rates(P>0.05).The mutation rate of EGFR in female patients was significantly higher than that in male patients(P<0.05)but had no correlation with the age,smoking status,and clinical stage of patients with non–small cell lung cancer(P>0.05).The EGFR mutation rate may be related to the degree of tumor differentiation.Conclusions:Among patients with lung adenocarcinoma in Kelamayi(city in Xinjiang),EGFR mutations were more frequently detected in female patients,and the main sites of mutations were exons 19 and 21.

Prevalence of Myocilin Gene Mutation in Adult-Onset Primary Open Angle Glaucoma and Non-Glaucoma Subjects Who Are Indigenes of Rivers State, Nigeria

Background: Glaucoma is the leading cause of irreversible blindness incapacitating over 80 million people worldwide. Several pathogenetic mechanisms have been postulated to explain the optic nerve damage that occur in POAG among which genetic predisposition is prominent. Gene-Linkage-based studies have identified genes associated with POAG: Myocilin, Optineurin, WDR36, Tank-Binding Kinase (TBK1) and APbb-2. Objective: To investigate the prevalence of myocilin gene mutation in adult-onset POAG patients and non-glaucoma subjects who are indigenes of Rivers State. Methodology: In this comparative cross-sectional study, 393 POAG patients attending the Glaucoma Clinic of UPTH were compared with 393 age and sex-matched phenotypically normal participants. Clinical assessment combined with findings from clinical records was used. Venous blood was obtained for genomic analyses. Extracted DNA was sequenced with specific primers for myocilin and polymerase chain reaction. Zymo-Bead Genomic DNA kit protocol was used to detect allelic differences. Results: Total of 786 participants participated in the study. The mean age was 59.8 ± 11.8 years. The prevalence of myocilin gene mutation (MYOC) in the study population was 5.3%, in the POAG group was 8.4%, and 2.3% in the non-glaucoma group. This observed difference was statistically significant (p = 0.001). Location of the mutant myocilin gene was in GLC1A 171638779, 171638703, 171638610 and 171638608. Conclusion: Mutations in myocilin gene are associated with adult-onset POAG in Rivers State. Its relevance as a biomarker for diagnosis of adult-onset POAG needs further investigations.

Progress in clinical diagnosis and treatment of colorectal cancer with rare genetic variants

Targeted therapy is crucial for advanced colorectal cancer(CRC) positive for genetic drivers. With advances in deep sequencing technology and new targeted drugs, existing standard molecular pathological detection systems and therapeutic strategies can no longer meet the requirements for careful management of patients with advanced CRC. Thus, rare genetic variations require diagnosis and targeted therapy in clinical practice. Rare gene mutations, amplifications, and rearrangements are usually associated with poor prognosis and poor response to conventional therapy. This review summarizes the clinical diagnosis and treatment of rare genetic variations, in genes including erb-b2 receptor tyrosine kinase 2(ERBB2), B-Raf proto-oncogene, serine/threonine kinase(BRAF), ALK receptor tyrosine kinase/ROS proto-oncogene 1, receptor tyrosine kinase(ALK/ROS1), neurotrophic receptor tyrosine kinases(NTRKs), ret proto-oncogene(RET), fibroblast growth factor receptor 2(FGFR2), and epidermal growth factor receptor(EGFR), to enhance understanding and identify more accurate personalized treatments for patients with rare genetic variations.

Detection of LAMA2 c.715C>G:p.R239G mutation in a newborn with raised creatine kinase: A case report

BACKGROUND We report a rare case of primary clinical presentation featuring elevated creatine kinase(CK)levels in a neonate,which is associated with the LAMA2 gene.In this case,a heterozygous mutation in exon5 of the LAMA2 gene,c.715C>G(resulting in a change of nucleotide number 715 in the coding region from cytosine to gua-nine),induced an amino acid alteration p.R239G(No.239)in the patient,repre-senting a missense mutation.This observation may be elucidated by the neonatal creatine monitoring mechanism,a phenomenon not previously reported.CASE SUMMARY We analysed the case of a neonate presenting solely with elevated CK levels who was eventually discharged after supportive treatment.The chief complaint was identification of increased CK levels for 15 d and higher CK values for 1 d.Ad-mission occurred at 18 d of age,and despite prolonged treatment with creatine and vitamin C,the elevated CK levels showed limited improvement.Whole exo-me sequencing revealed the presence of a c.715C>G mutation in LAMA2 in the newborn,correlating with a clinical phenotype.However,the available informa-tion offers insufficient evidence for clinical pathogenicity.CONCLUSION Mutations in LAMA2 are associated with the clinical phenotype of increased neonatal CK levels,for which no specific treatment exists.Whole genome sequen-cing facilitates early diagnosis.

Mutational landscape of TP53 and CDH1 in gastric cancer

In this editorial we comment on an article published in a recent issue of the World J Gastrointest Surg.A common gene mutation in gastric cancer(GC)is the TP53 mutation.As a tumor suppressor gene,TP53 is implicated in more than half of all tumor occurrences.TP53 gene mutations in GC tissue may be related with clinical pathological aspects.The TP53 mutation arose late in the progression of GC and aided in the final switch to malignancy.CDH1 encodes E-cadherin,which is involved in cell-to-cell adhesion,epithelial structure maintenance,cell polarity,differentiation,and intracellular signaling pathway modulation.CDH1 mutations and functional loss can result in diffuse GC,and CDH1 mutations can serve as independent prognostic indicators for poor prognosis.GC patients can benefit from genetic counseling and testing for CDH1 mutations.Demethylation therapy may assist to postpone the onset and progression of GC.The investigation of TP53 and CDH1 gene mutations in GC allows for the investigation of the relationship between these two gene mutations,as well as providing some basis for evaluating the prognosis of GC patients.

Genetic variation features of neonatal hyperbilirubinemia caused by inherited diseases

BACKGROUND Genetic factors play an important role in neonatal hyperbilirubinemia(NH)caused by genetic diseases.AIM To explore the characteristics of genetic mutations associated with NH and analyze the correlation with genetic diseases.METHODS This was a retrospective cohort study.One hundred and five newborn patients diagnosed with NH caused by genetic diseases were enrolled in this study between September 2020 and June 2023 at the Second Affiliated Hospital of Xiamen Medical College.A 24-gene panel was used for gene sequencing to analyze gene mutations in patients.The data were analyzed via Statistical Package for the Social Sciences 20.0 software.RESULTS Seventeen frequently mutated genes were found in the 105 patients.Uridine 5'-diphospho-glucuronosyltransferase 1A1(UGT1A1)variants were identified among the 68 cases of neonatal Gilbert syndrome.In patients with sodium taurocholate cotransporting polypeptide deficiency,the primary mutation identified was Na+/taurocholate cotransporting polypeptide Ntcp(SLC10A1).Adenosine triphosphatase 7B(ATP7B)mutations primarily occur in patients with hepatolenticular degeneration(Wilson's disease).In addition,we found that UGT1A1 and glucose-6-phosphate dehydrogenase mutations were more common in the high-risk group than in the low-risk group,whereas mutations in SLC10A1,ATP7B,and heterozygous 851del4 mutation were more common in the low-risk group.CONCLUSION Genetic mutations are associated with NH and significantly increase the risk of disease in affected newborns.

Eucaryotic DNA Methylation and Gene Mutation

5-methylcytosine (m5C) as a rare base exists in eucaryotic genomes, it is a normal constituent of many eucaryotic DNA, whose existence is a character of eucaryotic DNA. In the regular physiological conditions, cytosine residue of eucaryotic DNA is methylated to be popular. Up to the present, many people consider that the m5C may be mutation hotspots by the m5C deamination leading to gene mutation. Our theoretical investigations indicated that the spontaneous mutation caused by the transition of G - C-A - T, in eukaryotic DNA, may be a result caused by the tautomer changing base pairs and may also be caused by other factor actions, however it could not be caused by the deamination of m5C.

Relations of Budd-Chiari syndrome to prothrombin gene mutation

BACKGROUND: Budd-Chiari syndrome (BCS) is a type of disease characterized by portal hypertension and/or hy- pertension of the inferior vena cava (IVC) due to the ob- struction of the hepatic veins (HV) and/or intrahepatic IVC outlet. Being etiologically complicated and obscure, BCS can be acquired or idiopathic and several gene muta- tions may be contributable. This study was to explore whether prothrombin gene mutation (F G20210A) takes part in the pathogenesis of BCS and to investigate their cor- relativity. METHODS: In 38 proven BCS patients and 70 controls, polymerase chain reaction-restriction fragment length poly- morphism (PCR-RFLP) was used to find F G20210A mutation. To detect whether there are any mutations, four steps were taken: purification of genome DNA from whole blood, amplification of special fragment by polymerase chain reaction, digestion of the fragment via restriction en- donuclease, and analysis of results by polyacrylamide gel electrophoresis. RESULTS: F G20210A mutation was not detected in all patients and controls. CONCLUSIONS: No F G20210A mutation exists in Chi- nese patients with BCS, nor correlativity between the oc- currence of BCS and F G20210A mutation. The etiology of BCS in the Chinese needs further investigation.

Mutation Analysis of AVPR2 and AQP2 Gene in Chinese Patients with Congenital Nephrogenic Diabetes Insipidus

To detect mutations of the aquaporin 2 gene（AQP2） and the arginine vasopressin V2 receptor gene（AVPR2） of Chinese congenital nephrogenic diabetes insipidus, and to establish the foundation for further studying the emergence mechanism of the disease and clinical diagnosis, all the exons and part of introns of AQP2 and AVPR2 genes were amplified with intronic primers, using genomic DNA extracted from three patients with congenital nephrogenic diabetes insipidus and two mothers as template, PCR product was ligated into a T-vector and then sequenced. The result was compared with the database sequence to identify the mutable sites via a BLAST search, the incidence of every mutation was analyzed, and the putative transcription factor binding sites that maybe disturbed were analyzed by MAPPER. Mutation g.1394A〉G in exon 3 of AVPR2 was detected in all the subjects, g.861C〉T（S167L） in exon 2 of AVPR2 and IVS1＋3G〉A in intron of AQP2 were detected, respectively, in two patients, and c.836A〉C in 3′ untranslated region of AQP2 was detected in two patients and one mother. Four mutations were identified. g.1394A〉G of AVPR2 and c.836A〉C of AQP2 have high incidence in patients with nephrogenic diabetes insipidus. Detection on the two sites may become auxiliary diagnosis index of congenital nephrogenic diabetes insipidus.

Genetic aberration in primary hepatocellular carcinoma:correlation between p53 gene mutation and loss-of-heterozygosity on chromosome 16q21-q23 and 9p21-p23

To elucidate the molecular pathology underlying the development of hepatocellular carcinoma (HCC), we used 41 highly polymorphic microsatellite markers to examine 55 HCC and corresponding non-tumor liver tissues on chromosome 9, 16 and 17. Loss-of-heterozygosity (LOH) is observed with high frequency on chromosomal region 17p13 (36/55, 65%), 9p21-p23 (28/55, 51%), 16q21-q23 (27/55, 49%) in tumors. Meanwhile, microsatellite instability is rarely found in these microsatellite loci. Direct sequencing was performed to detect the tentative mutation of tumor suppressor genes in these regions: p53, MTS1/p16, and CDH1/E-cadherin. Within exon 5-9 of p53 gene, 14 out of 55 HCC specimens (24%) have somatic mutations, and nucleotide deletion of this gene is reported in HCC for the first time. Mutation in MTS1/pl6 is found only in one tumor case. We do not find mutations in CDH1/E-cadherin. Furthermore, a statistically significant correlation is present between p53 gene mutation and loss of chromosome region 16q21q23 and 9p21-p23, which indicates that synergism between p53 inactivation and deletion of 16q21-q23 and 9p21-p23 may play a role in the pathogenesis of HCC. Genetic aberration in hepatocellular

Frequency of primary iron overload and HFE gene mutations (C282Y,H63D and S65C) in chronic liver disease patients in north India

AIM:To identify the frequency of iron overload and study the three mutations in the HFE gene (C282Y,H63D,and S65C) in patients with chronic liver disorders (CLD) and controls. METHODS:To identify patients with iron overload (transferrin saturation > 45% in females and > 50% in males and serum ferritin > 1000 ng/mL) we evaluated 236 patients with CLD,including 59 with non-alcoholic steatohepatitis (NASH),22 with alcoholic liver disease (ALD),19 of cirrhosis due to viruses (HBV,HCV),and 136 with cryptogenic cirrhosis. Mutations of the HFE gene were analyzed by PCR-RE. hundred controls were screened for iron status and the mutations. RESULTS:Seventeen patients with CLD showed evidence of iron overload. Fifteen cases of iron overload had cryptogenic cirrhosis and two had ALD. None of the controls showed iron overload. We did not find any individual with 282Y or 65C either in the cases or in the controls. The prevalence of H63D heterozygosity was 12% in normal individuals,14.8% in 236 patients (16.9% in NASH,13.6% in ALD,26.3% in viral and 12.5% in cryptogenic cirrhosis) and the overall prevalence was 13.98%. Only two of the 17 patients with primary iron overload were heterozygous for H63D. One patient with NASH and one normal individual who were homozygous for H63D showed no iron overload.CONCLUSION:Primary iron overload in Indians is nonHFE type,which is different from that in Europeans and further molecular studies are required to determine the defect in various iron regulatory genes.

ANALYSIS OF C-HA-RAS GENE AMPLIFICATION AND MUTATION IN LARYNGEAL CARCINOMA

In order to study the altered molecular events during laryngeal carcinogenesis and elucidate the role of Haras oncogene amplification and mutation. we have examined their profile by polymerase chain reaction (PCR) and selective oligonucleotide hybridization. We analyzed the mutational status of codon 12 of Haras in 22 laryngeal carcinomas and 10 normal tissues. and found that 7 of 22 laryngeal carcinomas contained a Ha-ras mutation at codon 12. The frequency of mutation was 32%. None of the normal tissues revealed mutation. Moreover. no amplification was found in cancers when compared to the normal. Ourfindings indicated that the activated Ha-ras gene existed in laryngeal carcinoma. and activation of the Haras gene by mutation at codon 12 might play a key role in laryngeal carcinogenesis.