|Ahead of print
Extended-spectrum of KRAS and NRAS mutations in lung cancer tissue specimens obtained with bronchoscopy
Muserref Basdemirci1, Adil Zamani2, Ayse G Zamani3, Siddika Findik4, Mahmut S Yildirim3
1 Department of Medical Genetics, Konya Training and Research Hospital, Konya, Turkey
2 Department of Pulmonary Medicine, Meram Medical Faculty, Necmettin Erbakan University, Konya, Turkey
3 Department of Medical Genetics, Meram Medical Faculty, Necmettin Erbakan University, Konya, Turkey
4 Department of Pathology, Meram Medical Faculty, Necmettin Erbakan University, Konya, Turkey
|Date of Submission||28-Aug-2019|
|Date of Decision||06-Sep-2019|
|Date of Acceptance||10-Jun-2020|
|Date of Web Publication||21-Jun-2021|
Department of Medical Genetics, Konya Training and Research Hospital, Konya
Source of Support: None, Conflict of Interest: None
Background: Mutations in the RAS genes, HRAS, KRAS, and NRAS, are the most common modifications in many types of human tumors and are found in approximately 30% of all human cancers. These mutations are usually found in codons 12, 13, or 61.
Methods: The aim of this study is to evaluate mutations in codons 59, 117, and 146 of KRAS and NRAS genes in addition to codons 12,13, and 61 of KRAS gene in lung cancer tissue specimens obtained with bronchoscopy. KRAS and NRAS mutation analyses with pyrosequencing were performed on DNA isolated from formalin-fixed paraffin-embedded (FFPE) tissue samples of 64 patients histopathologically diagnosed as lung cancer after bronchoscopic biopsy.
Results: In all, 20 patients (31.2%) had mutations in KRAS gene (8/27 squamous cell carcinoma, 8/11 adenocarcinoma, 3/16 small cell carcinoma, and 1/1 pleomorphic carcinoma). The most common mutation in codon 12 was in c.35G>T (G12V). When the mutation rate of adenocarcinoma (72.7%) and squamous cell carcinoma (22.9%) patients was compared with each other, a statistically significant difference was observed (P = 0.008). There were no mutations in codons 59, 117, or 146 of KRAS and NRAS genes in patients with lung cancer.
Conclusion: In this study, we firstly examined mutations in codons 59, 117, and 146 of KRAS and NRAS genes in addition to codons 12, 13, and 61 of KRAS gene in Turkish lung cancer patients both in non-small cell lung cancer and small cell lung cancer. Although no mutation was detected in codons 59, 117, and 146 of KRAS and NRAS genes, the frequency of KRAS gene mutation was higher than the rate of mutation in both Asian and Western countries, and multicenter studies including more cases should be performed to further explore our results.
Keywords: Bronchoscopy, KRAS, lung cancer, mutation, NRAS
The absence of mutations in codons 59, 117 and 146 of KRAS and NRAS genes suggests that mutations in these codons perhaps don't contribute to pathogenesis of lung cancer in Turkey.
|How to cite this URL:|
Basdemirci M, Zamani A, Zamani AG, Findik S, Yildirim MS. Extended-spectrum of KRAS and NRAS mutations in lung cancer tissue specimens obtained with bronchoscopy. Indian J Cancer [Epub ahead of print] [cited 2021 Jul 27]. Available from: https://www.indianjcancer.com/preprintarticle.asp?id=318901
| » Introductıon|| |
Non-small cell lung cancer (NSCLC), which is the most common histological type of lung cancer, has an increasing incidence and the highest cancer-related mortality rate worldwide in recent years. Results from previous studies have shown that somatic mutations in genes such as EGFR, KRAS, BRAF, NRAS, PIK3CA, Her-2, and TP53 are associated with the efficacy of epidermal growth factor receptor tyrosine kinase inhibitors, metastasis, or total survival. Therefore, molecular analyses of mutations in these genes are widely used in the management of individualized NSCLC patients' treatment.,
The incidence of oncogene mutations in NSCLC patients varies from society to society. In Western countries, the oncogene most commonly mutated in patients with NSCLC (and highly associated with smoking) is Kirsten rat sarcoma viral oncogene homolog (KRAS). In humans, there are four RAS isoforms encoded by three genes (KRAS, HRAS, and NRAS). RAS proteins are small GTPases which function as molecular switches that control signaling pathways for cell proliferation and regulation of cell survival. Irregular RAS signals are associated with oncogenesis and a class of developmental disorders called RASopathies. KRAS is the most commonly mutated RAS isoform (69% of RAS-mutant patients) found in approximately 20–25% of lung adenocarcinomas (ADC) in western countries and in 10–15% of cases in Asia. NRAS mutations with potential susceptibility to MEK inhibitors occur in lower rates in lung cancers (adenocarcinoma: 0.9%, squamous cell carcinoma: 1.2%)., However, to our knowledge, there is no extensive study of NRAS mutations.
The aim of this study is to evaluate mutations in 59, 117, and 146 codons of KRAS and NRAS genes in addition to 12, 13, and 61 codons of KRAS gene in bronchoscopic materials of patients with lung cancer.
| » Methods|| |
Consecutive patients who were suspected to have lung cancer because of signs, symptoms, and imaging findings on chest radiography, thoracic computed tomography, and/or fluorodeoxyglucose positron-emission tomography underwent fiberoptic bronchoscopy. Fiberoptic bronchoscopy using an Olympus BF-1T60 bronchoscope (Olympus Corp., Tokyo, Japan) was performed in 64 patients with endoscopically visible tumoral lesions between January 2014 and June 2016. Exclusion criteria for this study were as follows: patients under the age of 18 years, unfit to undergo an endoscopy, and unwillingness to provide written informed consent. Biopsy specimens were obtained with disposable oval-cup forceps (jaw outside diameter 1.8 mm). All bronchoscopies were performed by a single bronchoscopist. The study was approved by the medical ethics committee of the university. All patients that participated in the study signed informed consent release forms.
Demographic data collection
Patients' demographic characteristics, smoking status, and histopathological subtypes were extracted from electronic medical records (Hospital Information Management System).
A total of 64 formalin-fixed paraffin-embedded (FFPE) bronchoscopic tissue samples of patients, which were histopathologically diagnosed as lung cancer, were obtained from the pathology laboratory. Of the 64 samples, 48 were NSCLCs (35 squamous cell carcinomas, 11 adenocarcinomas, 1 large cell carcinoma, and 1 pleomorphic carcinoma) and 16 were SCLCs.
DNA isolation from FFPE tissue
For each specimen, a total of three sections and one corresponding hematoxylin and eosin-stained section were taken. For a maximum measure of tumor material, tumor-rich areas on the hematoxylin and eosin-stained slide were marked by a pathologist. Genomic DNA was isolated from the selected areas by using the QIAamp DNA FFPE Tissue Kit (Qiagen, Germany) according to the manufacturer's protocol. The concentration and quality of extracted DNA samples were measured by NanoDrop 2000c spectrophotometer (Thermo Scientific, USA). All isolated DNA samples were maintained at 4°C before use.
The mutational analysis of codon 59, 117, 146 of the KRAS and NRAS genes in addition to codon 12, 13, 61 of the KRAS gene was performed by pyrosequencing. The Therascreen KRAS Pyro Kit (Qiagen, Germany) and Therascreen RAS Extension Pyro Kit (Qiagen, Germany) were used to query the mutation status of codon 12, 13, and 61 of KRAS gene and codon 59, 117 and 146 of KRAS and NRAS genes, respectively. Target regions for mutation analysis of KRAS and NRAS genes were amplified by polymerase chain reaction (PCR) (Sensoquest, Thermocycler 48, Germany). PCR was conducted in a total volume of 25 μL, using the following reagents:
12.5 μL 2x PCR master mix, 2.5 μL 10x CoralLoad, 1 μL each PCR primer, 4 μL H2O (supplied) and 5 μL genomic DNA. Thermal cycle program for amplification was carried out as follows: the initial activation step at 95°C for 15 minutes was followed by 42 cycles of denaturation at 95°C for 20 seconds, annealing at 53°C for 30 seconds, and extension at 72°C for 20 seconds, with a final extension step of 5 minutes at 72°C. All PCR products were immobilized using immobilization mix consisting of PyroMark Binding Buffer, Streptavidin Sepharose High-Performance beads (GE Healthcare), and high-purity water. The immobilized amplicons were eluted at PyroMark Q24 Vacuum Workstation (Qiagen) using the following reagents: Ethanol (70%), PyroMark Denaturation Solution, PyroMark Wash Buffer, and high-purity water. Then, each pyrosequencing sequence primer was annealed to the purified single-stranded PCR products on the wells of PyroMark Q24 plate and pyrosequencing was performed on a PyroMark Q24 system (Qiagen) with PyroMark Gold Q24 Reagents (Qiagen) following the manufacturer's instructions. Results were analyzed using PyroMark Q24 software. The targeted sequences for KRAS (codons 12, 13, 59, 61, 117, and 146) and NRAS (codons 59, 117, and 146) are listed below.
- KRAS codon 12 and 13: GGTGGCGTAGG
- KRAS codon 59: ACAGCAGGT
- KRAS codon 61: AGGTCAAGAG
- KRAS codon 117: ATAAATGTG
- KRAS codon 146: ATCAGCAAAG
- NRAS codon 59: ACAGCTGGA
- NRAS codon 117: AGTGTGA
- NRAS codon 146: CAGCCAAGAAC.
Pyrosequencing reading for codon 61 of KRAS is a reverse component of the target sequence (CTCTTGACCT) because its sequencing primer is a reverse primer.
Interpretation of analysis results and detection of low-level mutations
Control DNA was included in every run for comparison and as a control for background levels. The measured frequency of the control sample should be smaller or equal to the limit of blank (LOB). All samples were examined in relation to the limit of detection (LOD) and interpreted as follows:
Mutation frequency <LOD: Wild type
Mutation frequency ≥LOD and ≤LOD + 3% units: Potential low-level mutation
Mutation frequency >LOD + 3% units: Mutation
LOB and LOD were determined according to the recommendations in the Clinical and Laboratory Standards Institute (CLSI) Guideline EP17-A “Protocol for determination of limits of detection and limits of quantitation; approved guideline”.
T-test and χ2 test were used to compare the data. A P value of less than 0.05 was considered statistically significant. Statistical analysis of all data obtained from this study was performed using SPSS version 20.0 (SPSS Inc., Chicago, IL, USA).
| » Results|| |
The average age of the patients was 62 years (range: 41–84 years). Most patients were smokers and men, only two patients were women. The patients' characteristics are shown in [Table 1].
Twenty (31.2%) of the 64 patients had mutations in the KRAS gene: 14 mutations in codon 12 (21.9%), 2 mutations in codon 13 (3.1%), 3 mutations in codon 61 (4.7%), and 1 tumor showed a double mutation (codon 12 and 61) (3%). No mutation in codons 59, 117, and 146 of KRAS or the NRAS gene was observed in patients. The most common mutation in codon 12 was c.35G>T (G12V). [Table 2] shows the results of the KRAS and NRAS genes' mutational analysis of all patients.
|Table 2: KRAS and NRAS mutational analysis of bronchoscopic tissue samples of 64 patients|
Click here to view
KRAS mutations were identified in 17 of 48 NSCLC and 3 of 16 SCLC. Among the 17 KRAS mutations in NSCLC, 8 were in squamous cell carcinomas, 8 were in adenocarcinomas, and 1 was in a pleomorphic carcinoma. Although the KRAS mutations were more prevalent in the NSCLC patients than in the SCLC patients (17/48 (35.4%) versus 3/16 (18.8%)), there were no statistically significant differences between the two groups (P = 0.213). However, the KRAS mutation in adenocarcinomas was significantly more frequent compared with squamous cell carcinomas (P = 0.008). There were also no statistically significant differences in the KRAS mutational frequencies between ≤60 and >60 year old patients (P = 0.945). Interestingly, although KRAS and NRAS mutations are rare in SCLC, one SCLC patient had two mutations in codon 61 of the KRAS gene (c.182A>T (Q61L) and c.183A>C (Q61H)).
| » Discussion|| |
Changes in the genome affecting the expression or function of genes that control cell growth and differentiation are considered the main cause of cancer. The first gene family found to be mutated in human tumors is the RAS oncogene family. Point mutations in specific codons of RAS genes lead to the continuous activation of the RAS proteins, ultimately triggering uncontrolled cell proliferation. RAS oncogenes are activated in approximately 30% of malignant tumors in humans. The most mutated gene is the KRAS gene (22%), while NRAS (8%) and HRAS (3%) genes are less affected according to the COSMIC dataset.
Most of KRAS mutations (80%) occur in codons 12 or 13, whereas very few mutations are observed at codon 61. By contrast, approximately 60% of NRAS mutations are occur in codon 61 and 35% in codon 12. Mutations in codon 12, 13, or 61 of KRAS are reported as 20–30%, in patients with lung cancers, especially in NSCLC.
The incidence of KRAS mutations in lung cancer is dependent upon tumor histopathological subtypes, and reported in 22–34% of adenocarcinomas, 0–25% of squamous cell carcinomas, 8–33% of large cell carcinomas, and 8–11% of adenosquamous cell carcinomas. In our study, KRAS gene mutations were detected in 20 of 64 patients (31.2%), a higher mutation rate than in similar studies in the literature. Seventeen of the detected mutations (35.4%) were in patients with NSCLC and 3 (18.8%) were in cases with SCLC. There was no statistically significant difference between these two groups. In one of the cases with SCLC, double mutation was detected in codon 61 of KRAS.
In Western countries, KRAS mutation rate is higher in patients with NSCLC, especially in those with ADC (30–50). In contrast, most studies from East Asian regions reported a much lower mutation rate in patients with NSCLC than the rate reported in Western countries. However, the mutation rate of KRAS gene in patients with ADC was reported as >10%in 2 studies, including one study from Japan (13%) and one study from Korea (31.2%).,
In most studies that analyzed KRAS mutation status in NSCLC, the patient groups consisted adenocarcinoma cases. However the number of studies with squamous cell cancer cases is limited. In a largest study from Japan by Noda et al., the KRAS mutation rate was 8% (33 of 410 patients) in NSCLC, 9.2% (21 of 217 patients) in ADC and 5.5% (8 of 145 patients) in SCC. Another of the largest, prospective study from Asian patients with SCC by Kenmatsu et al., KRAS mutation rate was 4%. In a study with SCC patients from Prague by Vachtenheim et al., KRAS mutation rate was reported as 8% (9 of 118). In our report, we have summarized the results of the KRAS mutations studies in patients with NSCLC from different countries, including our results [Table 3].,,,,,,,,,,,,,,,,,,,,,,
|Table 3: Comparison of the mutation rates in KRAS gene in patients with NSCLC from different countries|
Click here to view
In the present study, the rate of KRAS mutation were 35.4% in NSCLC (17 of 48 patients), 72.7% in ADC (8 of 11 patients), and 22.9% in SCC (8 of 35 patients) as higher than the mutation rate in both East Asian and Western populations. KRAS mutation rates obtained in NSCLC cancer studies conducted in Turkey and the results of the present study are presented in [Table 4].,,,
|Table 4: Comparison of the mutation rates in KRAS gene in patients with NSCLC from different regions in Turkey|
Click here to view
High mutation rate in our study may be related to the low number of patients included in the study. In addition, the number of patients with adenocarcinoma who were included in the study was very low (17.2%). In many studies, only codon 12 of KRAS gene mutations were evaluated. In our study, we also looked for mutations in codon 13 or 61 of KRAS gene and detected mutations in these codons as well. These might partially explain higher mutation rate than other studies.
The number of studies evaluating KRAS gene mutations in SCLC was limited. Wakuda et al. detected KRAS gene mutation in only one of 60 Japanese patient with SCLC. In our study, we observed that KRAS mutations were detected more frequently (3 of 16 patients with SCLC) than in patients from Japan.
The reason of the changes in KRAS mutation rates between countries and regions are evaluated as ethnical and geographical differences.
All studies evaluating the frequency of KRAS gene mutations in lung cancer were focused mainly on codons 12, 13, or 61. In addition to these known KRAS mutations, a large-scale analysis which also includes codons 59, 117, and 146 of both KRAS and NRAS was performed in this study. Due to the design of the primers used for these regions, codons 58, 60, 118, 145, and 147 were also analyzed for mutations. No mutation was detected in these 8 codons of KRAS and NRAS. However, in studies with colorectal cancers, mutations were detected in these codons.,,, In fact, data have shown that these mutations play a role in response to chemotherapy. Based on our study, the absence of mutations in additional codons suggests that these mutations perhaps do not contribute to pathogenesis among patients in this region.
In conclusion, according to our literature review, this is the first study to evaluate extended spectrum of KRAS and NRAS mutations in lung cancer patients. KRAS mutation rate in codon 12, 13, or 61 reported herein is the highest among all reported series to date [Table 3]. In addition, there were no mutations in codons 59, 117 or 146 of KRAS and NRAS genes. In our opinion, multicenter studies should be conducted with a larger number of patients to further explore these findings.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
This work was supported by the Scientific Research Project of Necmettin Erbakan University (grant number 151518011).
Conflicts of interest
There are no conflicts of interest.
| » References|| |
Jing C, Mao X, Wang Z, Sun K, Ma R, Wu J, et al
. Next-generation sequencing-based detection of EGFR, KRAS
, BRAF, NRAS
, PIK3CA, Her-2 and TP53 mutations in patients with non-small cell lung cancer. Mol Med Rep 2018;18:2191-7.
Sutton BC, Birse RT, Maggert K, Ray T, Hobbs J, Ezenekwe A, et al
. Assessment of common somatic mutations of EGFR, KRAS
, BRAF, NRAS
in pulmonary non-small cell carcinoma using iPLEX® HS, a newhighly sensitive assay for the MassARRAY® System. PLoS One 2017;12:e0183715.
Tan DS, Mok TS, Rebbeck TR. Cancer genomics: Diversity and disparity across ethnicity and geography. J Clin Oncol 2016;34:91-101.
Ferrer I, Zugazagoitia J, Herbertz S, John W, Paz-Ares L, Schmid-Bindert G. KRAS
-Mutant non-small cell lung cancer: From biology to therapy. Lung Cancer 2018;124:53-64.
Mo SP, Coulson JM, Prior IA. RAS variant signalling. Biochem Soc Trans 2018;46:1325-32.
Ohashi K, Sequist LV, Arcila ME, Lovly CM, Chen X, Rudin CM, et al
. Characteristics of lung cancers harboring NRAS
mutations. Clin Cancer Res 2013;19:2584-91.
NCCLS. Protocols for Determination of Limits of Detection and Limits of Quantitation; Approved Guideline. NCCLS document EP17-A [ISBN 1-56238-551-8]. NCCLS, 940 West Valley Road, Suite 1400, Wayne, Pennsylvania 19087-1898 USA, 2004.
Bos JL. Ras oncogenes in human cancer: A review. Cancer Res 1989;4:4682-9.
Prior IA, Lewis PD, Mattos C. A comprehensive survey of Ras mutations in cancer. Cancer Res 2012;72:2457-67.
Aviel-Ronen S, Blackhall FH, Shepherd FA, Tsao MS. K-ras mutations innon-small-cell lung carcinoma: A review. Clin Lung Cancer 2006;8:30-8.
Wu CC, Hsu HY, Liu HP, Chang JW, Chen YT, Hsieh WY, et al
. Reversed mutation rates of KRAS
and EGFR genes in adenocarcinoma of the lung in Taiwan and their implications. Cancer 2008;113:3199-208.
Kosaka T, Yatabe Y, Endoh H, Kuwano H, Takahashi T, Mitsudomi T. Mutations of the epidermal growth factor receptor gene in lung cancer: Biological and clinical implications. Cancer Res 2004;64:8919-23.
Cho JY, Kim JH, Lee YH, Chung KY, Kim SK, Gong SJ, et al.
Correlation between K-ras gene mutation and prognosis of patients with nonsmall cell lung carcinoma. Cancer 1997;79:462-67.
Noda N, Matsuzoe D, Konno T, Kawahara K, Yamashita Y, Shirakusa T. K-ras gene mutations in non-small cell lung cancer in Japanese. Oncol Rep 2001;8:889-92.
Kenmotsu H, Serizawa M, Koh Y, Isaka M, Takahashi T, Taira T, et al
. Prospective genetic profiling of squamous cell lung cancer and adenosquamous carcinoma in Japanese patients by multitarget assays. BMC Cancer 2014;14:786.
Vachtenheim J, Horáková I, Novotná H, Opáalka P, Roubková H. Mutations of K-ras oncogene and absence of H-ras mutations in squamous cell carcinomas of the lung. Clin Cancer Res 1995;1:359-65.
Fukuyama Y, Mitsudomi T, Sugio K, Ishida T, Akazawa K, Sugimachi K. K-ras and p53 mutations are an independent unfavourable prognostic indicator in patients with non-small-cell lung cancer. Br J Cancer 1997;75:1125-30.
Suzuki M, Shigematsu H, Hiroshima K, Iizasa T, Nakatani Y, Minna JD, et al.
Epidermal growth factor receptor expression status in lung cancer correlates with its mutation. Hum Pathol 2005;36:1127-34.
Bae NC, Chae MH, Lee MH, Kim KM, Lee EB, Kim CH, et al
. EGFR, ERBB2, and KRAS
mutations in Korean non-small cell lung cancer patients. Cancer Genet Cytogenet 2007;173:107-13.
Lung ML, Wong M, Lam WK, Lau KS, Kwan S, Fu KH, et al
. Incidence of ras oncogene activation in lung carcinomas in Hong Kong. Cancer 1992;70:760-3.
Tam IY, Chung LP, Suen WS, Wang E, Wong MC, Ho KK, et al
. Distinct epidermal growth factor receptor and KRAS
mutation patterns in non-small cell lung cancer patients with different tobacco exposure and clinicopathologic features. Clin Cancer Res 2006;12:1647-53.
Wang YC, Lee HS, Chen SK, Yang SC, Chen CY. Analysis of K-ras gene mutations in lung carcinomas: Correlation with gender, histological subtypes, and clinical outcome. J Cancer Res Clin Oncol 1998;124:517-22.
Zhang G, Sun Y, Wang M. [Detection of K-ras oncogene activation in human lungcancer and its possible clinical application]. Zhonghua Jie He He Hu Xi Za Zhi 1995;18:282-317.
Pesek M, Benesova L, Belsanova B, Mukensnabl P, Bruha F, Minarik M. Dominance of EGFR and insignificant KRAS
mutations in prediction of tyrosine-kinase therapy for NSCLC patients stratified by tumor subtype and smoking status. Anticancer Res 2009;29:2767-73.
Rodenhuis S, van de Wetering ML, Mooi WJ, Evers SG, van Zandwijk N, Bos JL. Mutational activation of the K-ras oncogene. A possible pathogenetic factor in adenocarcinoma of the lung. N Engl J Med 1987;317:929-35.
Boch C, Kollmeier J, Roth A, Stephan-Falkenau S, Misch D, Grüning W, et al
. The frequency of EGFR and KRAS
mutations in non-small cell lungcancer (NSCLC): Routine screening data for central Europe from a cohort study. BMJ Open 2013;3:e002560.
Husgafvel-Pursiainen K, Hackman P, Ridanpää M, Anttila S, Karjalainen A, Partanen T, et al
. K-ras mutations in human adenocarcinoma of the lung: Association with smoking and occupational exposure to asbestos. Int J Cancer 1993;53:250-6.
Cadranel J, Mauguen A, Faller M, Zalcman G, Buisine MP, Westeel V, et al
. Impact of systematic EGFR and KRAS
mutation evaluation on progression-free survival and overall survival in patients with advanced non-small-cell lung cancer treated by erlotinib in a French prospective cohort (ERMETIC project--part 2). J Thorac Oncol 2012;7:1490-502.
Rosell R, Monzo M, Molina F, Martinez E, Pifarre A, Moreno I, et al
. K-ras genotypes and prognosis in non-small-cell lung cancer. Ann Oncol 1995;6(Suppl 3):15-20.
Keohavong P, DeMichele MA, Melacrinos AC, Landreneau RJ, Weyant RJ, Siegfried JM. Detection of K-ras mutations in lung carcinomas: Relationship to prognosis. Clin Cancer Res 1996;2:411-18.
Graziano SL, Gamble GP, Newman NB, Abbott LZ, Rooney M, Mookherjee S, et al
. Prognostic significance of K-ras codon 12 mutations in patients with resected stage I and II non-small-cell lung cancer. J Clin Oncol 1999;17:668-75.
Sarkar FH, Li Y, Vallyathan V. Molecular analysis of p53 and K-ras in lung carcinomas of coal miners. Int J Mol Med 2001;8:453-9.
Pao W, Wang TY, Riely GJ, Miller VA, Pan Q, Ladanyi M, et al
mutations and primary resistance of lung adenocarcinomas to gefitinib or erlotinib. PLoS Med 2005;2:e17.
Massarelli E, Varella-Garcia M, Tang X, Xavier AC, Ozburn NC, Liu DD, et al
mutation is an important predictor of resistance to therapy with epidermal growth factor receptor tyrosine kinase inhibitors in non-small-cell lung cancer. Clin Cancer Res 2007;13:2890-6.
Marks JL, Broderick S, Zhou Q, Chitale D, Li AR, Zakowski MF, et al
. Prognostic and therapeutic implications of EGFR and KRAS
mutations in resected lung adenocarcinoma. J Thorac Oncol 2008;3:111-6.
Vatan O, Bilaloglu R, Tunca B, Cecener G, Gebitekin C, Egeli U, et al
. Low frequency of p53 and k-ras codon 12 mutations in non-small cell lung carcinoma (NSCLC) tumors and surgical margins. Tumori 2007;93:473-7.
Bircan S, Baloglu H, Kucukodaci Z, Bircan A. EGFR and KRAS
mutations in Turkish non-small cell lung cancer patients: A pilot study. Med Oncol 2014;31:87.
Demiray A, Yaren A, Karagenc N, Bir F, Demiray AG, Karagür ER, et al
., The Frequency of EGFR and KRAS
mutations in the Turkish population with non-small cell lung cancer and their response to erlotinib therapy. Balkan J Med Genet 2018;21:21-6.
Buyuksimsek M, Togun M, Oguz KI, Bisgin A, Boga I, Tohumcuoglu M, et al
. Results of liquid biopsy studies by next generation sequencing in patients with advanced stage non-small cell cung cancer: Single center experience from Turkey. Balkan J Med Genet 2019;22:17-24.
Wakuda K, Kenmotsu H, Serizawa M, Koh Y, Isaka M, Takahashi S, et al
. Molecular profiling of small cell lung cancer in a Japanese cohort. Lung Cancer 2014;84:139-44.
Edkins S, O'Meara S, Parker A, Stevens C, Reis M, Jones S, et al
. Recurrent KRAS
codon 146 mutations in human colorectal cancer. Cancer Biol Ther 2006;5:928-32.
Janakiraman M, Vakiani E, Zeng Z, Pratilas CA, Taylor BS, Chitale D, et al
. Genomic and biological characterization of exon 4 KRAS
mutations in human cancer. Cancer Res 2010;70:5901-11.
Richman S, Chambers P, Hemmings G, Taylor M, Seymour M, Quirke P. Identification of NRAS and KRAS
-146 mutations and double-mutant cases in 817 patients with advanced colorectal cancer (aCRC). J Pathol 2011;224:S7.
Van Cutsem E, Lenz HJ, Köhne CH, Heinemann V, Tejpar S, Melezínek I, et al
. Fluorouracil, leucovorin, andirinotecan plus cetuximab treatment and RAS mutations in colorectal cancer. J Clin Oncol 2015;33:692-700.
Douillard JY, Oliner KS, Siena S, Tabernero J, Burkes R, Barugel M, et al
. Panitumumab-FOLFOX4 treatment and RAS mutations incolorectal cancer. N Engl J Med 2013;369:1023-34.
[Table 1], [Table 2], [Table 3], [Table 4]