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This study was aimed to evaluate the influence of Human Leukocyte Antigens- G (HLA-G) gene polymorphisms on the risk of rheumatoid arthritis (RA). In the present study, blood samples were collected from 100 rheumatoid arthritis patients and 100 healthy controls. Serum levels of HLA-G in both patients and controls were measured using ELISA kit which was shown a higher significant differences (p< 0.05) in comparison between them (539.3 ng/ml and 139.3ng/ml) respectively. The frequency of the allele and genotypes in the patient groups and control groups were determined using Polymerase Chain Reaction (PCR) for 14 bp polymorhisms in exon 8 (rs66554220) while direct sequencing analysis was done to determine exon 2 (rs1130355) (G 1850 A) SNPs of human leucocyte antigens- G (HLA- G). There was statistically significant difference in all genotypes of HLA-G14-bp of exon 8 in RA patients in comparison with controls. The probability of homozygote genotype of insertion was (0.006), homozygote genotype of deletion was (0.003) and for heterozygote of insertion was (0.000) in comparison between RA patients and controls. From the results of odd ratio (OR) found that existence of homozygotes of insertion give protection effect from disease O.R= 0.44 while heterozygotes of deletion act as risk factor for disease O.R= 3.31. Homozygotes of deletion had no effect because was not found in patients groups. From the sequencing results of exon 2 of HLA-G gene found the mutation occur in position 1850 G>A which give three genotypes (GG, AG and AA). Calculations of genotypes frequency for exon 2 showed that GG and AA genotypes was associated with the disease with p- value (0.000) for both genotypes. While AG genotype showed no association with disease p value (0.449).From the results of odd ratio found that GG and AA of exon 2 gave protection effect from disease O.R( 0.29 and 0.76 ) respectively, while AG genotype acted as risk factor for disease O.R= 4.0. [ABSTRACT FROM AUTHOR]

Pathogenic variants in the Parkin-gene (PRKN) are among the most common genetic causes of early onset Parkinson's disease (EOPD). Patients with EOPD can present with atypical clinical features and misdiagnosis is frequent. Here, we report a clinical phenotype with atypical signs and symptoms of a 35-year-old male patient with EOPD caused by a compound heterozygous PRKN-gene deletion of exons 2 and 4. After the initial diagnosis of stiff person syndrome, the patient was admitted to our department for a second opinion after 8 years of untreated disease progression. The patient presented with prominent spastic paraparesis pronounced on the right side and hyperreflexia as well as Parkinsonism with rigidity predominantly affecting the upper limbs, bradykinesia, and resting tremor. In the diagnostic assessment, magnetic evoked potentials to the anterior tibial muscles showed a low amplitude on the right side, compatible with pyramidal tract disturbance. However, an MRI of the head and the spine did not show any pathologies or atrophy. A [123I] FP-CIT SPECT scan revealed profoundly and left-pronounced reduced striatal uptake suggesting a neurodegenerative Parkinson's syndrome. Even though an acute levodopa challenge did not show marked improvement of symptoms, the chronic levodopa challenge with up to 450 mg/day significantly reduced the rigidity and bradykinesia. Surprisingly, spastic paraparesis and hyperreflexia diminished under dopaminergic treatment. Finally, genetic analysis by next-generation sequencing via copy number variant analysis (CNV) and multiplex ligation-dependent probe amplification (MLPA) confirmed compound heterozygous deletions of exons 2 and 4 in the PRKN-gene. As presented in this case, the awareness of atypical clinical symptoms of EOPD is essential to prevent misdiagnosis in young patients.

Background: Leptin hormone, encoded by leptin (LEP) gene is involved in many biological and physiological processes in the body. Polymorphism in LEP gene has been observed and correlated with a variety of reproductive and productive traits in several sheep breeds worldwide, but its role has not been much studied in local sheep breeds of Pakistan. The present study was conducted to analyze polymorphism in LEP gene in Lohi breed of sheep. Methods: Subsequent to statistical analysis (generalized linear model), 18 animals were selected randomly from the flock for blood samples collection followed by DNA extraction, amplification using PCR prior to sequencing. The amplified product of exon 2 and partial intron 2 regions of LEP gene was 268bp. Results: Molecular analysis showed a heterozygous condition i.e. C>Y at position 15 and 18 in exon 2. The data on average daily weight gain (ADG) from birthday to 90 days were used for association study, while environmental effects were minimized by means of generalized linear model. Association of polymorphisms in LEP gene with ADG did not yield any significant results. Conclusion: In conclusion, analysis of LEP gene sequence verified the existence of genetic changes in Lohi sheep. Further investigations are needed to find variations that might be linked with traits of economic importance for upcoming breeding program sand marker-assisted selection.

Abstract Background Tumor suppressor gene p16 promoter hypermethylation has been widely studied in colorectal cancer (CRC), yet its clinicopathological significance remains controversial. The methylation alterations of other regions within p16 gene are still rarely researched. The present study aimed to explore the methylation changes of p16 gene body in CRC and to find whether they were associated with clinicopathological staging of CRC. Methods Paired colorectal cancer tissues and corresponding adjacent normal tissues from 30 CRC patients were collected. The methylation levels of two CpG islands within p16 gene body, exon 1 and exon 2, were accurately assessed simultaneously by a LC-MS/MS method. The p16 protein expressions were assessed by immunohistochemistry assay. Statistical analyses were carried out using SPSS 17.0 software. Heat-map analysis was carried out by HemI 1.0 software. Results In the present study, CRC tissues showed more highly methylated than adjacent normal tissues at both CpG islands of p16 gene. And exon 2 hypermethylation was higher and more frequent than exon 1. The ROC curve analysis showed that the simultaneous use of both indicators had excellent sensitivity and specificity for distinguishing CRC tissues and adjacent normal tissues. Following, the methylation level of p16 exon 1/2 was negatively related to p16 protein expression. Further correlation analysis revealed that p16 exon 1 hypermethylation was associated with N/Dukes staging (p = 0.033), and p16 exon 2 hypermethylaiton was associated with T staging (p = 0.035). Conclusions The p16 gene body was remarkably hyper-methylated in CRC tissues and associated with p16 protein expression and cancer clinicopathological staging. The combination of p16 exon 1 and exon 2 could better reflect the overall methylation status of p16 gene body and provide potential biomarkers of CRC.

Abstract Background Breast carcinogenesis is a multistep process involving genetic and epigenetic changes. Tumor tissues are frequently characterized by gene-specific hypermethylation and global DNA hypomethylation. Aberrant DNA methylation levels have, however, not only been found in tumors, but also in tumor-surrounding tissue appearing histologically normal. This phenomenon is called field cancerization. Knowledge of the existence of a cancer field and its spread are of clinical relevance. If the tissue showing pre-neoplastic lesions is not removed by surgery, it may develop into invasive carcinoma. Methods We investigated the prevalence of gene-specific and global DNA methylation changes in tumor-adjacent and tumor-distant tissues in comparison to tumor tissues from the same breast cancer patients (n = 18) and normal breast tissues from healthy women (n = 4). Methylation-sensitive high resolution melting (MS-HRM) analysis was applied to determine methylation levels in the promoters of APC, BRCA1, CDKN2A (p16), ESR1, HER2/neu and PTEN, in CDKN2A exon 2 and in LINE-1, as indicator for the global DNA methylation extent. The methylation status of the ESR2 promoter was determined by pyrosequencing. Results Tumor-adjacent and tumor-distant tissues frequently showed pre-neoplastic gene-specific and global DNA methylation changes. The APC promoter (p = 0.003) and exon 2 of CDKN2A (p

Objective: The P21waf is a tumor-suppressor protein encoded by CDKN1A gene. In this study, we evaluated P21waf expression and CDKN1A exon 2 mutation and their relationships with clinicopathological parameters and cancer development in salivary adenoid cystic carcinoma (ACC). Patients and Methods: Forty paraffin blocks from patients with salivary ACC were collected. Immunohistochemical staining was performed using P21 antibody. Genomic DNAs were extracted from the deparaffinized sections of the embedded tissue. Exon 2 of CDKN1A gene was amplified by PCR and the PCR products were sequenced. Spearman’s correlation coefficient, Fisher’s exact test, and Kruskal-Wallis test were used for data analysis. Results: A significant inverse correlation was observed between P21 expression and histologic grade (p=0.033, r=-0.338). The correlation of tumor size with recurrence (p=0.048) and tumor stage (p=0.046) was also evidenced. No mutation was detected in the exon 2 of CDKN1A gene. Conclusions: Regarding the association of P21 expression and histologic grade as a major prognostic indicator of ACC, P21 may be a useful prognostic indicator in ACC. On the other hand, CDKN1A exon 2 mutation seems inapplicable as a risk factor for ACC development.

Studies performed on farm animals like cattle and pig have shown that there has been a relationship between leptin gene (LEP) and carcass meat quality, milk production and content, and economic parameters such as reproduction and food consumption. There has been scarce research conducted related to leptin gene of sheep and especially goat. The aim of the study is to reveal the genetic structures of goats living in Turkey through nucleotide sequence analysis in targeted zones of LEP gene Exon 2 and Intron 2 of Anatolian Black, Kilis and Angora goat breeds which are commonly fed in Anatolia. According to the sequence analysis results of each three breeds, Anatolian Black goat breed have the highest haplotype number with nucleotide and haplotype diversity both in exon 2 and intron 2. There was only one haplotype found in both exon 2 and intron 2 in Angora goat breed. There was no nucleotide diversity found in individuals belonging to Angora goat breed. Taking the regions analyzed for LEP gene into consideration, it is seen that Anatolian Black goat breed has the highest genetic diversity among other goat breeds fed in Anatolia. Future studies upon the LEP gene in goats should take into account of increasing the sample size and of base in order to obtain more useful information for better understanding the gene structure.

The tyrosine kinase receptor RET, which is the protein product of the RET gene, is involved in the development of the mammalian nervous system that causes Hirschsprung’s disease (HSCR). RETs are cell surface molecules that are expressed in cells derived from the neural crest. The purpose of this study was to investigate the polymorphism of the RET gene in HSCR in the Yogyakarta population. Genomic DNA was extracted from surgically removed bowel tissues of 54 unrelated HSCR patients. Exon 2 of the RET gene was amplified by polymerase chain reaction (PCR) and analyzed by restriction fragment length polymorphism (RFLP). Molecular results were compared with clinical performance of Hirschsprung patients. RET polymorphism was detected in exon 2 in all of the 54 Indonesian HSCR patients. The allelic distribution of the c135GàA polymorphism in the RET exon 2 indicated that the A allele was more frequent in patients than in control individuals (chi-square test, p= 0.001). Thus the RET variant allele A is over-represented in patients affected with the HSCR phenotype. Polymorphism of exon 2 of the RET gene was found in sporadic Hirschsprung’s disease in the Yogyakarta population, which suggests that the RET gene plays important roles in the pathogenesis of HSCR.

Objective: Familial Mediterranean fever (FMF) is the most common autoinflammatory disease. Most of the identified disease-causing mutations are located on exon 10. As the number of studies about the effect of the exonal location of the mutation and its phenotypic expression is limited, we aimed to investigate whether the exonic location of the Mediterranean fever (MEFV) mutation has an effect on the clinical manifestation in patients with FMF. Methods: Study population was derived from the main FMF registry that included 2246 patients from 15 different rheumatology clinics. We categorized the mutations according to their exon locations and retrieved the clinical and demographic information from the database. Results: Patients having the MEFV mutations on exon 2 or 10 (n:1526) were divided into three subgroups according to the location of the MEFV mutations: Group 1 (exon 2 mutations), Group 2 (exon 10 mutations), and Group 3 (both exon 2 and exon 10 mutations). Group 2 patients were of a significantly younger age at onset, and erysipel-like erythema, arthritis, amyloidosis, and a family history of FMF were more common in this group. Conclusion: Patients with FMF and exon 10 mutations show more severe clinical symptoms and outcome. Exon 2 mutations tend to have a better outcome. [ABSTRACT FROM AUTHOR]

Objective: Familial Mediterranean fever (FMF) is the most common autoinflammatory disease. Most of the identified disease-causing mutations are located on exon 10. As the number of studies about the effect of the exonal location of the mutation and its phenotypic expression is limited, we aimed to investigate whether the exonic location of the Mediterranean fever (MEFV) mutation has an effect on the clinical manifestation in patients with FMF. Methods: Study population was derived from the main FMF registry that included 2246 patients from 15 different rheumatology clinics. We categorized the mutations according to their exon locations and retrieved the clinical and demographic information from the database. Results: Patients having the MEFV mutations on exon 2 or 10 (n:1526) were divided into three subgroups according to the location of the MEFV mutations: Group 1 (exon 2 mutations), Group 2 (exon 10 mutations), and Group 3 (both exon 2 and exon 10 mutations). Group 2 patients were of a significantly younger age at onset, and erysipel-like erythema, arthritis, amyloidosis, and a family history of FMF were more common in this group. Conclusion: Patients with FMF and exon 10 mutations show more severe clinical symptoms and outcome. Exon 2 mutations tend to have a better outcome. [ABSTRACT FROM AUTHOR]

Background: Tumor suppressor gene p16 promoter hypermethylation has been widely studied in colorectal cancer (CRC), yet its clinicopathological significance remains controversial. The methylation alterations of other regions within p16 gene are still rarely researched. The present study aimed to explore the methylation changes of p16 gene body in CRC and to find whether they were associated with clinicopathological staging of CRC.Methods: Paired colorectal cancer tissues and corresponding adjacent normal tissues from 30 CRC patients were collected. The methylation levels of two CpG islands within p16 gene body, exon 1 and exon 2, were accurately assessed simultaneously by a LC-MS/MS method. The p16 protein expressions were assessed by immunohistochemistry assay. Statistical analyses were carried out using SPSS 17.0 software. Heat-map analysis was carried out by HemI 1.0 software.Results: In the present study, CRC tissues showed more highly methylated than adjacent normal tissues at both CpG islands of p16 gene. And exon 2 hypermethylation was higher and more frequent than exon 1. The ROC curve analysis showed that the simultaneous use of both indicators had excellent sensitivity and specificity for distinguishing CRC tissues and adjacent normal tissues. Following, the methylation level of p16 exon 1/2 was negatively related to p16 protein expression. Further correlation analysis revealed that p16 exon 1 hypermethylation was associated with N/Dukes staging (p = 0.033), and p16 exon 2 hypermethylaiton was associated with T staging (p = 0.035).Conclusions: The p16 gene body was remarkably hyper-methylated in CRC tissues and associated with p16 protein expression and cancer clinicopathological staging. The combination of p16 exon 1 and exon 2 could better reflect the overall methylation status of p16 gene body and provide potential biomarkers of CRC. [ABSTRACT FROM AUTHOR]

Background: Breast carcinogenesis is a multistep process involving genetic and epigenetic changes. Tumor tissues are frequently characterized by gene-specific hypermethylation and global DNA hypomethylation. Aberrant DNA methylation levels have, however, not only been found in tumors, but also in tumor-surrounding tissue appearing histologically normal. This phenomenon is called field cancerization. Knowledge of the existence of a cancer field and its spread are of clinical relevance. If the tissue showing pre-neoplastic lesions is not removed by surgery, it may develop into invasive carcinoma.Methods: We investigated the prevalence of gene-specific and global DNA methylation changes in tumor-adjacent and tumor-distant tissues in comparison to tumor tissues from the same breast cancer patients (n = 18) and normal breast tissues from healthy women (n = 4). Methylation-sensitive high resolution melting (MS-HRM) analysis was applied to determine methylation levels in the promoters of APC, BRCA1, CDKN2A (p16), ESR1, HER2/neu and PTEN, in CDKN2A exon 2 and in LINE-1, as indicator for the global DNA methylation extent. The methylation status of the ESR2 promoter was determined by pyrosequencing.Results: Tumor-adjacent and tumor-distant tissues frequently showed pre-neoplastic gene-specific and global DNA methylation changes. The APC promoter (p = 0.003) and exon 2 of CDKN2A (p < 0.001) were significantly higher methylated in tumors than in normal breast tissues from healthy women. For both regions, significant differences were also found between tumor and tumor-adjacent tissues (p = 0.001 and p < 0.001, respectively) and tumor and tumor-distant tissues (p = 0.001 and p < 0.001, respectively) from breast cancer patients. In addition, tumor-adjacent (p = 0.002) and tumor-distant tissues (p = 0.005) showed significantly higher methylation levels of CDKN2A exon 2 than normal breast tissues serving as control. Significant correlations were found between the proliferative activity and the methylation status of CDKN2A exon 2 in tumor (r = -0.485, p = 0.041) and tumor-distant tissues (r = -0.498, p = 0.036).Conclusions: From our results we can conclude that methylation changes in CDKN2A exon 2 are associated with breast carcinogenesis. Further investigations are, however, necessary to confirm that hypermethylation of CDKN2A exon 2 is associated with tumor proliferative activity. [ABSTRACT FROM AUTHOR]

The tyrosine kinase receptor RET, which is the protein product of the RET gene, is involved in the development of the mammalian nervous system that causes Hirschsprung’s disease (HSCR). RETs are cell surface molecules that are expressed in cells derived from the neural crest. The purpose of this study was to investigate the polymorphism of the RET gene in HSCR in the Yogyakarta population. Genomic DNA was extracted from surgically removed bowel tissues of 54 unrelated HSCR patients. Exon 2 of the RET gene was amplified by polymerase chain reaction (PCR) and analyzed by restriction fragment length polymorphism (RFLP). Molecular results were compared with clinical performance of Hirschsprung patients. RET polymorphism was detected in exon 2 in all of the 54 Indonesian HSCR patients. The allelic distribution of the c135GàA polymorphism in the RET exon 2 indicated that the A allele was more frequent in patients than in control individuals (chi-square test, p= 0.001). Thus the RET variant allele A is over-represented in patients affected with the HSCR phenotype. Polymorphism of exon 2 of the RET gene was found in sporadic Hirschsprung’s disease in the Yogyakarta population, which suggests that the RET gene plays important roles in the pathogenesis of HSCR.

OBJECTIVE: The present study evaluated the association between lactotransferrin (LTF) gene polymorphism (exon 2, A/G, Lys/Arg) and dental caries. MATERIAL AND METHODS: A convenience sample of 110 individuals, 12 years old, was divided into: group 1, 48 individuals without caries experience (DMFT=0), and group 2, 62 subjects with caries experience (DMFT>1). DNA was obtained from a mouthwash with 3% glucose solution, followed by a scrapping of the oral mucosa. After DNA purification, polymerase chain reaction (PCR), single strand conformation polymorphism (SSCP) was performed to access the study polymorphism. The LTF A/G (Lys/Arg) polymorphism had been previously reported as located in exon 1. RESULTS: Allele 1 of the study polymorphism was associated with low DMFT index and showed a protective effect against caries experience (OR=0.16, IC=0.03-0.76, p=0.01). CONCLUSIONS: Lactotransferrin A/G (exon 2, Lys/Arg) polymorphism was associated with susceptibility to dental caries in 12-year-old students.

Background: The Major Histocompatibility Complex (MHC) is a genomic region containing genes with crucial roles in immune responses. MHC class I and class II genes encode antigen-presenting molecules expressed on the cell surface. To counteract the high variability of pathogens, the MHC evolved into a region of considerable heterogeneity in its organization, number and extent of polymorphism. Studies of MHCs in different model species contribute to our understanding of mechanisms of immunity, diseases and their evolution. Camels are economically important domestic animals and interesting biomodels. Three species of Old World camels have been recognized: the dromedary (Camelus dromedarius), Bactrian camel (Camelus bactrianus) and the wild camel (Camelus ferus). Despite their importance, little is known about the MHC genomic region, its organization and diversity in camels. The objectives of this study were to identify, map and characterize the MHC region of Old World camelids, with special attention to genetic variation at selected class MHC II loci. Results: Physical mapping located the MHC region to the chromosome 20 in Camelus dromedarius. Cytogenetic and comparative analyses of whole genome sequences showed that the order of the three major sub-regions is "Centromere - Class II - Class III - Class I". DRA, DRB, DQA and DQB exon 2 sequences encoding the antigen binding site of the corresponding class II antigen presenting molecules showed high degree of sequence similarity and extensive allele sharing across the three species. Unexpectedly low extent of polymorphism with low numbers of alleles and haplotypes was observed in all species, despite different geographic origins of the camels analyzed. The DRA locus was found to be polymorphic, with three alleles shared by all three species. DRA and DQA sequences retrieved from ancient DNA samples of Camelus dromedarius suggested that additional polymorphism might exist. Conclusions: This study provided evidence that camels possess an MHC comparable to other mammalian species in terms of its genomic localization, organization and sequence similarity. We described ancient variation at the DRA locus, monomorphic in most species. The extent of molecular diversity of MHC class II genes seems to be substantially lower in Old World camels than in other mammalian species. [ABSTRACT FROM AUTHOR]

Background Familial Mediterranean Fever (FMF), characterized by recurrent fever and inflammation of serous membranes, is an autosomal recessive disease caused by mutations in the Mediterranean fever (MEFV) gene. Around 296 mutations have been reported to date. Methods Two two-generation Turkish families with a total of four members diagnosed with FMF clinically were screened with DNA sequencing performed on exon 2 and exon 10 of the MEFV genes. Then, complete exome sequencing analysis of MEFV gene was done for four patients in whom novel mutation was detected. Results A novel single base Guanine (G) insertion mutation in the coding region of MEFV gene, named c.2330dupG (p.Gln778Serfs*4 or Q778SfsX4) resulting in a mutated Pyrin/Marenostrin protein was identified. Conclusions This is the first report of a new mutation in exon 10 of the MEFV gene in two Turkish families. This novel pattern of insertion mutation may provide important information for further studies on FMF pathogenesis. [ABSTRACT FROM AUTHOR]

The DQB1 locus is located in the major histocompatibility complex (MHC) class II region and involved in immune response. We identified 20 polymorphic sites in a 228 bp fragment of exon 2, one of the most critical regions of the MHC DQB1 gene, in 60 Nigerian goats. Four sites are located in the peptide binding region, and 10 amino acid substitutions are peculiar to Nigerian goats, compared with published sequences. A significantly higher ratio of nonsynonymous/synonymous substitutions ( dN/ dS) suggests that allelic sequence evolution is driven by balancing selection ( P < 0.01). In silico functional analysis using PANTHER predicted that substitution P56R, with a subPSEC score of −4.00629 (P deleterious = 0.73229), is harmful to protein function. The phylogenetic tree from consensus sequences placed the two northern breeds closer to each other than either was to the southern goats. This first report of sequence diversity at the DQB1 locus for any African goat breed may be useful in the search for disease-resistant genotypes. [ABSTRACT FROM AUTHOR]

Abstract: Abnormal tau cleavage is prominent in the neurofibrillary degeneration characteristic of Alzheimer’s disease (AD) and related tauopathies. We recently showed that cleaved human tau is secreted by specific mechanisms when overexpressed. Here we examined the effect of expressing N-terminal and full length tau constructs in transiently and stably transfected neuronal lines. We show that secreted tau exhibits a cleavage pattern similar to CSF-tau from human AD patients and that tau secretion is specifically inhibited by the presence of the exon 2 insert. These results suggest that tau secretion may play a hitherto unsuspected role in AD and related tauopathies. [Copyright &y& Elsevier]

Potential links between fish life history traits, an immune investment as measured by variability of the MHC genes and parasitism were analysed in 14 species of cyprinid fish. The hypothesis of the diversity of MHC genes being driven by high parasite diversity, i.e. species richness, was tested and a potential relationship between the MHC diversity and fish life-history traits including adult mortality rate, fecundity, longevity and maturity was investigated. Molecular techniques (SSCP and sequencing) were applied to analyse the MHC nucleotide diversity of the exons 2 and 3 of DAB genes belonging to the MHC class IIB. The comparative analyses, using phylogenetic independent contrasts, revealed a negative relationship between parasite species richness and adult fish mortality rate. We also found a positive relationship between nucleotide diversity of the exon 2 and parasite species richness. Our results suggest that fish species, of which populations are exposed to high parasite pressure, in terms of high parasite species richness, maintain a high genetic diversity of the exon 2 of the MHC genes (presenting the peptide binding regions), allowing them to decrease their natural mortality rate. [ABSTRACT FROM AUTHOR]

Background: Rat Sarcoma (RAS) protein encoded Guanosine Triphosphate (GTP-ase) activity, known as a switch of cell proliferation. The mutation of this protein alters the early stage of carcinogenesis and along with the interaction with other oncogene drivers and environmental factors affect the clinical characteristics and prognosis in cancer patients, particularly lung cancer., Objective: This study aims to determine the Kristen Rat Sarcoma (KRAS) mutation in lung cancer patients in North Sumatera and evaluate factors that might contribute in the development of lung cancer in the absence of KRAS mutation., Methods: This was a retrospective cohort study enrolled 44 subjects age > 18 year with the diagnosis of lung cancer. Histopathology preparation was obtained from surgery, bronchoscopy, and percutaneus needle biopsy then formed as paraffin-block. KRAS mutation was analyzed using Polymerase Chain Reaction (PCR) method with specific primer of exon 2 for evaluating the expression of RAS protein then continued with Sanger Sequencing Method at 12th and 13th codon., Results: The majority of subjects were male, age > 40 years old, bataknese, heavy smoker, with Adenocarcinoma. Almost all the subjects showed the expression of exon 2 of RAS protein in PCR examinations. However, Sequencing analysis using Bioedit Software, BLASTs and Finch T showed GGT GGC as protein base 219-224 which represented 12th and 13th Codon 12 and 13. The results interpreted there was no mutations of exon 2 of KRAS in North Sumatera Population., Conclusion: The absence of KRAS mutation in exon 2 in several ethnics in North Sumatera populations was not the main factors of lung cancer., Competing Interests: There are no conflicts of interest., (© 2021 Noni Novisari Soeroso, Fannie Rizki Ananda, Andika Pradana, Setia Putra Tarigan, Elisna Syahruddin, Dimas Ramadhian Noor.)