Distribution of KRAS and BRAF Mutations in Metastatic Colorectal Cancers in Turkish Patients

Regional and Gender-Based Distribution of KRAS Mutations in Metastatic Colorectal Cancer Patients in Turkey: An Observational Study

Background and Objectives: KRAS genes are among the most prominent oncogenes that trigger tumor formation in colorectal cancer (CRC) and serve as predictive biomarkers for resistance to anti-EGFR therapies in metastatic colorectal cancer (mCRC) patients. However, the prevalence and mutation spectrum of the KRAS gene family in mCRC patients in Turkey have not been sufficiently analyzed. This study investigates the frequency and distribution of mutations in the KRAS gene family across different regions of Turkey and examines gender-related variations. Materials and Methods: This multicenter observational study included 2458 histologically confirmed mCRC patients collected from 52 centers across Turkey. In a central laboratory, KRAS mutations in codons 12 and 13 were analyzed using polymerase chain reaction (PCR). Statistical analyses were performed using chi-square tests and Monte Carlo simulations, with a significance threshold set at p < 0.05. Results: Depending on the region, KRAS mutations were detected in 45% of patients, ranging from 39.6% to 47.5%. The mutation rate was significantly higher in female patients (48.8%) compared to male patients (42.6%) (p = 0.002). Codon 12 mutations were more frequent than codon 13 mutations. G12D, G12V, and G13D mutations accounted for 80% of all detected mutations. The G12V mutation was prevalent in female patients (p = 0.007). Based on region, mutation diversity was similar, and no statistically significant difference was found (p > 0.05). Conclusions: This large-scale, multicenter study provides the most comprehensive dataset of KRAS mutations in mCRC patients in Turkey. This study revealed regional trends, as well as gender differences. The findings highlight the importance of routine KRAS genotyping in guiding personalized treatment strategies, especially regarding candidate selection for anti-EGFR therapies. Further research is required to elucidate the prognostic and therapeutic implications of specific KRAS mutations.

Tumor profiling of KRAS, BRAF, and NRAS gene mutations in patients with colorectal cancer: A Lebanese major center cohort study

BACKGROUND

In the era of precision medicine, treatment schemes for advanced Colorectal (CRC) disease include monoclonal antibodies which block the epidermal growth factor receptor (EGFR) implicated in tumor proliferation, invasion, migration and neovascularization. Resistance to these agents has been correlated with activating downstream mutations in KRAS, BRAF and NRAS genes, among others, leading to constitutive activation of the EGFR axis bypassing EGFR blockade. The assessment of tumor RASandBRAFmutational status has thus become standard clinical practice. While multiple investigations reported roughly mutations rates of 40% in KRAS, 7% in NRAS and 5-15 % in BRAF, numbers vary across different populations with limited data specifically from the Middle East.

METHODS

This is a retrospective observational Laboratory information system (LIS) chart review of all the patients with pathologically confirmed colorectal carcinoma (CRC) or metastatic CRC who underwent KRAS, NRAS and/or BRAF mutational analysis testing at the Molecular Diagnostics Laboratory of the American University of Beirut Medical Center (AUBMC) from January 2012 to December 2018, inclusive. Data retrieved included the results of mutation testing performed for KRAS, NRAS and BRAF genes, the age, gender, and tumor location for each patient. Analysis of the mutations was performed using polymerase chain reaction (PCR) hybridization StripAssay® (ViennaLab, Vienna, Austria).

RESULTS

130 (47.6%) out of 273 histologically confirmed CRC cases, had positive KRAS mutations, namely in codons 12 (82%), 13 (17%), 146 (1.5%), 117 (0.75%), or 61 (0.75%). Two patients had two concomitant mutations: 12 + 12 (different mutations) and 12 + 146. Of 203 CRC cases tested for NRAS mutations, 16 (7.8%) were found to be positive for a mutation in codon 12 (37.5%), 61 (37.5%), or 13 (12.5%). Two patients had two concomitant mutations: 12 + 13 and 59 + 61. Of 172 CRC cases tested for BRAF mutations, 2 (1.2 %) were positive for the V600E -.

CONCLUSION

This retrospective study is the first to report the frequencies of KRAS, NRAS and BRAF gene mutations in a Lebanese CRC cohort diagnosed and managed at a tertiary care center. The frequencies of the studied somatic gene mutations were similar to previously reported cohorts in other populations however the rate of BRAF mutation was lower in this cohort than expected.

KRAS mutations in patients with colorectal cancer in Libya

Large prospective clinical trials have demonstrated that colorectal cancers (CRCs) with wild-type KRAS respond favorably to anti-epidermal growth factor receptor treatment, thus making mutational analysis obligatory prior to treatment. In our study, frozen CRC tissues from Libyan patients were analyzed for KRAS and HRAS mutations in codons 12/13 by direct sequencing and the correlations with clinical and pathological parameters were investigated. A total of 34 CRC cases, comprising 19 men and 15 women (age range, 24-87 years), were subjected to systematic analysis for RAS mutations. Although HRAS mutations were not detected in any of the patients in the study group, KRAS codon 12/13 mutations were present in 38.2% (13/34) of the patients. The frequent types of codon 12 mutations were glycine to aspartate (G12D, 46.1%); glycine to valine (G12V, 30.8%) and glycine to cysteine (G12C, 15.4%), while the codon 13 mutations were glycine to aspartate (G13D, 7.7%). G→A mutations occurred in 53.8% (7/13) of the patients, while G→T mutations occurred in 46.2% (6/13) of the patients. Mutations occurred at the first base of codon 12 or 13 in 2/13 (15.4%) and at the second base in 11/13 (84.6%) patients. There was no significant association between clinicopathological characteristics and KRAS mutation status, except the site of the tumors harboring KRAS mutations, which was as follows: The frequency was higher among tumors located in the left colon (8/13, 61.5%) compared to other sites (P=0.027). KRAS mutations were correlated with advanced age, with 10/13 being aged >50 years and affected 8/15 female patients (53%) compared with 5/19 male patients (26%). The highest frequency of KRAS mutations was observed in highly differentiated CRCs (8/13).

Catalog of Lung Cancer Gene Mutations Among Chinese Patients

Background: Detailed catalog of lung cancer-associated gene mutations provides valuable information for lung cancer diagnosis and treatment. In China, there has never been a wide-ranging study cataloging lung cancer-associated gene mutations. This study aims to reveal a comprehensive catalog of lung cancer gene mutations in china, focusing on EGFR, ALK, KRAS, HER2, PIK3CA, MET, BRAF, HRAS, and CTNNB1 as major targets. Additionally, we also aim to correlate smoking history, gender, and age distribution and pathological types with various types of gene mutations. Patients and Methods: A retrospective data acquisition was conducted spanning 6 years (2013-2018) among all patients who underwent lung cancer surgeries not bronchial or percutaneous lung biopsy at three major tertiary hospitals. Finally, we identified 1,729 patients who matched our inclusion criteria. Results: 1081 patients (62.49%) harbored EGFR mutation. ALK (n = 42, 2.43%), KRAS (n = 201, 11.62%), CTNNB1 (n = 28, 1.62%), BRAF (n = 31, 1.79%), PIK3CA (n = 51, 2.95%), MET (n = 14, 0.81%), HER2 (n = 47, 2.72%), HRAS (n = 3, 0.17%), and other genes(n = 232, 13.4%). Females expressed 55.38% vs. males 44.62% mutations. Among subjects with known smoking histories, 32.82% smokers, 67.15% non-smokers were observed. Generally, 51.80% patients were above 60 years vs. 48.20% in younger patients. Pathological types found includes LUADs 71.11%, SQCCs 1.68%, ASC 0.75%, LCC 0.58%, SCC 0.35%, ACC 0.17%, and SC 0.06%, unclear 25.19%. Conclusion: We offer a detailed catalog of the distribution of lung cancer mutations. Showing how gender, smoking history, age, and pathological types are significantly related to the prevalence of lung cancer in China.

Prevalence of RAS and BRAF mutations in metastatic colorectal cancer patients by tumor sidedness: A systematic review and meta-analysis

Studies have shown that the prevalence of RAS and BRAF mutations may differ by tumor sidedness among metastatic colorectal cancer (mCRC) patients. Both mutation status and tumor sidedness may impact survival and disease progression and RAS mutation status has been shown to predict response to anti‐epidermal growth factor receptor (EGFR) therapy. A systematic literature review and meta‐analysis were conducted to estimate the pooled prevalence of RAS and BRAF mutations by tumor sidedness in studies of mCRC patients. Forty‐four studies comprising 15 981 mCRC patients tested for RAS and/or BRAF mutations were included in the meta‐analyses. The prevalence of RAS mutations differed significantly by tumor side (32.4% among left‐sided tumors, 41.3% among right‐sided tumors; P = .017), as did the prevalence of KRAS mutations (35.8% among left‐sided tumors, 46.3% among right‐sided tumors; P < .0001) and BRAF mutations (4.3% among left‐sided tumors, 16.3% among right‐sided tumors; P < .0001). Among right‐sided tumors, the prevalence of RAS and KRAS mutations varied significantly by study design, with higher prevalence among observational studies than clinical trials, and there was significant variation by study location for the prevalence of KRAS mutations in left‐sided tumors and the prevalence of BRAF mutations in right‐sided tumors. These results help to better characterize the mCRC population to better inform clinicians and researchers. Few of the included studies reported overall or progression‐free survival (PFS) by both tumor sidedness and mutation status. As both of these factors may have prognostic impact, future studies should consider evaluating survival by these variables.

Prevalence of BRAF gene mutation in samples of primary and metastatic colorectal cancer: A meta-analysis

INTRODUCTION

Understanding the prevalence and biology of BRAF gene can improve the treatment methods of cancerous patients. This study aims to estimate the prevalence of BRAF gene mutation in samples of primary and metastatic colorectal cancer using meta-analysis method.

METHODS

We searched PubMed, Scopus, ScienceDirect, Ovid and Google Scholar motor engine using MeSH terms of relevant keywords. During the screening phase, titles, abstracts and full texts were reviewed and risk of bias was assessed for all selected papers based on Newcastle-Ottawa Scale (NOS) checklist. The results of the primary studies were combined using meta-analysis.

RESULTS

Of 95 eligible studies entered into the meta-analysis, prevalence of BRAF gene mutation had been assessed among 19,484 primary tumour samples as well as 12,256 metastatic samples. The total prevalence of BRAF gene mutation among primary tumour samples was estimated as of 10.16% (8.09-12.22) in the world, 0.41% (0-1.89) in EMRO region, 10.06% (7.54-12.59) in EURO region, 10.33% (7.24-13.43) in SEARO region and 11.33% (7.29-15.37) in WPRO region. The pooled estimates for BRAF gene mutation in metastatic samples were 6.53% (5.09-7.96), 8.07% (5.57-10.56), 5.38% (3.75-7.02) and 5.55% (1.72-9.38) for all regions, EURO, WPRO and PAHO regions respectively.

CONCLUSION

Our results showed evidences of BRAF gene mutation in one-tenth of primary colorectal tumour samples in EURO, PAHO, SEARO and WPRO regions which was considerably higher than that of the EMRO region.

BRAF Inhibitors for BRAF V600E Mutant Colorectal Cancers: Literature Survey and Case Report

The main method of fighting against colon cancer is targeted treatment. BRAF inhibitors, which are accepted as standard treatment for V600E mutant malign melanomas, are the newest approach for targeted treatment of V600E mutant colorectal cancers. In this case report, we share our experience about the use of BRAF inhibitor vemurafenib on a V600E mutant metastatic right colon adenocarcinoma patient. A 59-year-old male with only lung multiple metastatic V600E mutant right colon cancer presented to our clinic. The patient was evaluated and FOLFOX + bevacizumab treatment was initiated, which was then continued with vemurafenib. A remarkable response was achieved with vemurafenib treatment in which the drug resistance occurred approximately in the sixth month. Even though the patient benefited majorly from vemurafenib, he died on the 20th month of the diagnosis. The expected overall survival for metastatic V600E mutant colon adenocarcinoma patients is 4.7 months. BRAF inhibitors provide new treatment alternatives for V600E mutant colorectal cancers, with prolonged overall survival. BRAF inhibitors in combination with MEK inhibitors are reported as feasible treatment to overcome BRAF inhibitor drug resistance on which phase studies are still in progress. To conclude, BRAF inhibitors alone or in combination with other drugs provide a chance for curing BRAF V600E mutant colorectal cancer patients.

KRAS and NRAS Testing in Metastatic Colorectal Cancer in Central Iran (Tehran): A Review on Literature of the Middle East

Context: The incidence of colorectal cancer (CRC) in the past three decades in Iran has made it as a major public health burden. Aims: The aim of this study is to report the prevalence of KRAS and NRAS mutations in Iran and the correlation between KRAS mutation status with clinicopathological factors and survival.Materials and Methods: In a cross-sectional study, 144 patients were entered into the study based on the criteria. Age, sex, tumor site, grade, metastasis location, familial history, KRAS/NRAS status, and survival were checked for all patients, and the patients were followed for 1 year. DNA was extracted with FFPE QIAGEN kit and then polymerase chain reaction for amplification of gene segments of KRAS and NRAS genes. Results: The mean age at diagnosis was 52.9 years (range: 27–72 years) that 39.6% patients had age <50 years and 54.2% were men. KRAS mutation was significantly more in the patients with age ≥50 compared with KRAS wild type. Furthermore, the 6-month overall survival rate in KRAS mutation patients was significantly more than KRAS wild-type patients. Liver metastasis (72.9%) had the highest prevalence of metastasis in the patients, and Grade II with 64.6% had the most prevalence. Conclusions: The metastatic CRC was more prevalent in men than women, and the mean age varied around 50–60 years. The results showed that the present study had the highest prevalence of KRAS mutation in the Middle East and Pakistan with the lowest prevalence in CRC patients.

Effect of KRAS mutation status on efficacy of EGFR monoclonal antibody treatment in colorectal cancer

Colorectal cancer is one of the most common malignant tumors. With the development of economy and the improvement of living standard in China, which have resulted in great changes in lifestyle and eating habits, the incidence of colorectal cancer has increased year by year. Among all treatments currently available, targeted therapy is considered to be the most ideal treatment for metastatic colorectal cancer. KRAS mutation is closely related to the efficacy of targeted therapy for colorectal cancer. Thus, it is important to clarify the KRAS mutation status before targeted therapy is considered. This paper mainly elaborates the effect of KRAS mutation status on the efficacy of epidermal growth factor receptor monoclonal antibody treatment of colorectal cancer with regard to the structure and function of KRAS gene, KRAS mutations and heterogeneity.