Presence Of K-ras Gene Mutations Research Articles

KRAS-mutated non-small cell lung cancer: new therapy strategies

Lung cancer remains one of the most dangerous and most common cancers, requiring constant improvement of diagnostic and treatment methods. The genetic heterogeneity of lung cancer forces us to search for new therapeutic targets in an attempt to achieve greater effectiveness for certain groups of patients. The purpose of the study was to update current knowledge about lung adenocarcinoma with a mutation in the KRAS gene, to consider new opportunities for personalized treatment of KRAS-mutated NSCLC and to form an image of a Russian patient who is potentially indicated for targeted therapy. Material and methods. A search of available literature sources published in the Pubmed, Cochrane Library, Elibrary database was carried out, publications covering the period from 2008 to 2023 were included. Results. The article discussed molecular genetic testing, including NGS next generation sequencing, and its role in determining the presence of KRAS gene mutations in patients with lung cancer. the effectiveness of targeted drugs, such as Sotorasib and Adagrasib was also discussed. The mechanism of action is aimed at suppressing the activity of the mutant KRAS G12C protein, which can significantly improve patient survival prognosis. We obtained data on the results of testing 935 patients with non-squamous non-small cell lung cancer from various medical centers in Russia. The KRAS gene mutation was identified in 160 (17.1 %) patients, of whom 96 (10.3 %) had KRAS G12C variant. The KRAS mutation was determined by PCR in 44 patients and by NGS (including on the FoundationOne platform) in 111 patients. Clinical characteristics, such as gender, age, smoking status, PD-L1 expression level, presence of co-mutations (TP53, STK11, KEAP1, were largely similar between patients from real-world clinical practice and patients included in the CodeBreak100 study. Conclusion. The research results confirm the high effectiveness of Sotorasib and Adagrasib for patients with the KRAS G12C mutation and open up new prospects in the treatment of lung cancer. The clinical data obtained from Russian patients demonstrate consistency with the patient profile from registration studies of these drugs. This once again demonstrates the need to expand the range of molecular genetic testing for timely identification of this group of patients and prescribing the most effective treatment for them.

Mutation in the kras gene as a predictor of the effectiveness of immunotherapy for non-small cell lung cancer

The purpose of the study: to conduct a systematic literature review on the effectiveness and feasibility of using information on the presence of KRAS gene mutations (in different codons), TP 53 (KP), ST K11/LKB1 (KL), and KEAP mutations and the association of KRAS m with PD -L1 status in patients with non-small cell lung cancer (NSCLC ) as a predictor of the effectiveness of immunotherapy with immune checkpoint inhibitors.Material and Methods. The review includes data from randomized clinical trials and meta-analyses on the predictive value of KRAS mutation status for response to immunotherapy in patients with NSCLC over the past 10 years.Results. The presence of KRAS mutations in NSCLC patients could be a predictive factor for their response to immunotherapy, as several studies have demonstrated benefit from immunotherapy in these patients. The combination of KRAS mutation with TP 53 (KP) co-mutation predicts a better response to immunotherapy, while a combination with ST K11/LKB1 (KL) and KEAP 1 predicts a worse response (reduced response rate and overall and disease-free survival). In PD -L1-positive patients, the presence of KRAS mutation is associated with a better prognosis after treatment with immunotherapy. Moreover, the presence of KRAS mutation is associated with a worse response to first-line and subsequent-line chemotherapy, thus indicating a more promising use of immunotherapy in these patients.Conclusion. Identification of TP 53 (KP), ST K11/LKB1 (KL), and KEAP 1 co-mutations and the presence of KRAS mutation in addition to determination PD -L expression enable selection of patients who will obtain the greatest benefit from immunotherapy. In addition, the ability to determine KRAS mutation and co-mutation status using a liquid biopsy (with acceptable specificity and sensitivity) makes it possible to use this method for determining sensitivity to immunotherapy when it is not possible to obtain tumor sample (to determine PD 1-L1 expression).

Results of in vitro test-KRAStissue reagent kit test to determine indications for target therapy of patients diagnosed with colorectal cancer.

As subjects of the clinical trial, 44 samples of paraffin-fixed tissue were used from patients diagnosed with "colorectal cancer." In the course of clinical trials, 44 samples of paraffin-fixed tissue were analyzed in two series of experiments, that is, 88 clinical-laboratory experiments were carried out, of which 48 experiments with genomic DNA samples with the established negative status of the presence of KRAS gene mutations and 40 experiments with genomic DNA samples with the established positive status of the presence of KRAS gene mutations. Analysis and evaluation of the results of clinical laboratory tests of the medical product "Kit of Reagents for Determination of the Status of KRAS Gene Mutations by PCR-RV Method in a Sample of Human Genomic DNA from Samples of Paraffin-Fixed Tissue (Test-KRAS-tissue) according to TU 21.20.23-006-97638376-2016 "confirmed that it allows to carry out qualitative determination of the status of six mutations of the twelfth codon (Gly12Asp, Gly12Ala, Gly12Arg, Gly12Val, Gly12Ser, Gly12Cys) and one mutation of the thirteenth codon (Gly13Asp) the KRAS gene by real-time allele-specific PCR in human genomic DNA sample from paraffin-fixed tissue samples, with high diagnostic sensitivity rates of 90.9% and diagnostic specificity of 95.0% with a confidence probability of 90%. Reproducibility of results is 100%, which confirms the high reliability of the set.

Biomarkers in Colorectal Cancer: Current Research and Future Prospects.

Colorectal cancer (CRC) is a leading cause of death worldwide, despite progress made in detection and management through surgery, chemotherapy, radiotherapy, and immunotherapy. Novel therapeutic agents have improved survival in both the adjuvant and advanced disease settings, albeit with an increased risk of toxicity and cost. However, metastatic disease continues to have a poor long-term prognosis and significant challenges remain due to late stage diagnosis and treatment failure. Biomarkers are a key tool in early detection, prognostication, survival, and predicting treatment response. The past three decades have seen advances in genomics and molecular pathology of cancer biomarkers, allowing for greater individualization of therapy with a positive impact on survival outcomes. Clinically useful predictive biomarkers aid clinical decision making, such as the presence of KRAS gene mutations predicting benefit from epidermal growth factor receptor (EGFR) inhibiting antibodies. However, few biomarkers have been translated into clinical practice highlighting the need for further investigation. We review a range of protein, DNA and RNA-based biomarkers under investigation for diagnostic, predictive, and prognostic properties for CRC. In particular, long non-coding RNAs (lncRNA), have been investigated as biomarkers in a range of cancers including colorectal cancer. Specifically, we evaluate the potential role of lncRNA plasmacytoma variant translocation 1 (PVT1), an oncogene, as a diagnostic, prognostic, and therapeutic biomarker in colorectal cancer.

INVESTIGATION KRAS MUTATION IN CIRCULATION TUMOR DNA IN DIFFERENT STAGES OF COLORECTAL CANCER

To determine mutations in the plasma KRAS gene in patients with colorectal cancer was the aim of this study. The material was obtained from 44 patients with colorectal cancer of different stages (T1-4N0-2bM0-1c). Plasma for the presence of KRAS gene mutation in circulating tumor DNA was investigated using digital droplet polymerase chain reaction (PCR). KRAS mutations in circulating tumor DNA isolated from 1 ml of plasma were detected in 13 (30%) patients with cancer of different stages. Of these, with stage II, there were 3 patients, with III - 5 and with IV - 5. Patients who did not have mutations in 1 ml of plasma were analyzed for mutations of KRAS in circulating tumor DNA isolated from 3 ml of plasma. Five more patients with KRAS mutations were found with II and III stages. The highest concentrations of circulating tumor DNA with KRAS mutation were found in patients with stage IV. The increase in plasma volume to 3 ml did not lead to the identification of mutations in I stage. This study showed that digital droplet PCR allows identification of circulating tumor DNA with the KRAS mutations in patients with stage II-IV of colon cancer. The results can be used to determine the degree of aggressiveness of the tumor at different stages of the disease, but not the 1st, and it is recommended to use a plasma volume of at least 3 ml.

MiR-211 regulates the expression of RRM2 in tumoral metastasis and recurrence in colorectal cancer patients with a k-ras gene mutation.

Colorectal cancer (CRC) ranks as the third-leading cause of cancer-associated mortalities in Taiwan. The expression of ribonucleotide reductase M2 (RRM2) and p53R2 is associated with tumoral malignancy and progression in several types of cancer. The aim of the present study was to determine the association of p53R2/RRM2 with the upstream expression of microRNA (miR)-211 and the association of expression levels of p53, APC and k-ras with clinical outcomes in patients with CRC. The study consisted of 192 tumor tissue samples obtained from patients with CRC. Immunohistochemistry and direct sequencing of DNA were performed to analyze p53R2/RRM2 protein expression and p53/APC/k-ras gene mutations in these samples. The expression level of miR-211 was detected by reverse transcription-quantitative polymerase chain reaction. The results showed that the expression of p53R2 was lower and that of RRM2 was higher in patients with lymph node metastasis, distant metastasis, and late-stage CRC compared with patients without lymph node metastasis, distant metastasis and early-stage CRC. A high expression of RRM2 in patients had a negative effect on overall survival (OS) and disease-free survival (DFS) in CRC. Positive expression of RRM2 was detected in tumor tissues, and expression associated with the presence of k-ras gene mutation. Furthermore, it was detected that the upstream miR-211 expression was negatively associated with RRM2 expression in tumor tissues of patients with CRC. miR-211 expression was associated with survival and tumoral recurrence in patients with k-ras mutations. The present authors suggest that the downregulation of miR-211 and overexpression of RRM2 in tumor tissues of patients with CRC could be used to predict metastases and disease prognosis, particularly in patients with k-ras gene mutations.

K-ras gene mutations and loss of heterozygosity at the p53 gene locus relative to histological characteristics of mucin-producing tumors of the pancreas

Mucin-producing tumors (MPTs) of the pancreas accompanied by carcinomas usually include various grades of dysplasia in the ductal epithelium, and invasive areas are histologically similar to those of common invasive ductal carcinomas, suggesting that MPTs provide a good tool to investigate early stages of pancreatic carcinogenesis. Thus, to clarify genetic alterations in the early stage of pancreatic carcinogenesis, we analyzed K-ras gene mutations and loss of heterozygosity (LOH) at the p53 gene locus using 37 cases of MPTs harboring dysplastic epithelium. Further, we conducted an extended, multifocal microdissection analysis focusing on the histological features of ductal epithelium and the distribution of genetic alterations for 3 cases of MPT positive for LOH of the p53 gene to determine the relation to tumor progression. K-ras gene mutations were detected with high frequency in 50% or more cases of the adenomas (14 of 19), borderline tumors (4 of 7), and carcinomas (8 of 11), whereas LOH of the p53 gene was limited to carcinomas (3 of 5 informative cases, 60%) and always accompanied by K-ras gene mutation. Investigation of a total of 126 microdissection sites from 3 cases showed the presence of K-ras gene mutations in mild dysplasia and all (100%) regions of moderate or more marked dysplasia, whereas LOH of the p53 gene showed more gradual tendency to increase with grade from moderate dysplasia. In addition, the multifocal genetic analysis showed K-ras gene mutations to be widely distributed throughout tumors, whereas LOH of the p53 gene was localized to 1 or a few areas. Further, topographically delimited areas with the same histology in the same tumor did not always show the same genetic alteration. In conclusion, we could confirm that both the K-ras and p53 gene alterations occur in the intraductal stage of MPT, and the latter is superimposed on the former during the course of tumor progression. However, the pattern of association of histological features with genetic alteration differs from tumor to tumor. HUM PATHOL 31:795-803.

A relationship between K-ras gene mutations and some clinical and histologic variables in patients with primary colorectal carcinoma.

Mutations in the Kirsten ras 2 (K-ras) gene were described as early events in the process of colorectal carcinogenesis. The aim of this study was to find a possible relationship between the presence of K-ras mutation in samples of primary colorectal carcinomas and the clinico-pathological data of the investigated patients. Mutation in codon 12 of the K-ras gene was determined in 18 of 53 colorectal carcinomas (34%) in our group of patients. The presence of K-ras gene mutations was not related to gender, age of subject at diagnosis, staging or cancer location (p > 0.05). Sixteen of the 42 (38%) moderately differentiated carcinomas, and two of the eight (25%) well differentiated carcinomas contained K-ras mutation in codon 12, but none of the three poorly differentiated carcinomas contained the mutation. Moderately differentiated tumours contained an aspartate code GAT (in eight cases), a valine code GTT (in six cases), an alanine code GCT (in one case) and a serine code AGT (in one case) in codon 12. Well differentiated tumours contained only the valine code GTT (two cases). Our results show that the frequency of mutations in the K-ras gene in carcinomas in Central Europe is not different from the frequencies found in other parts of the world. The homogeneous incidence of K-ras mutation does not seem to be related to ethnic factors, dietary habits, or the composition of the diet.

Increased telomerase activities in human pancreatic duct adenocarcinomas.

Telomerase is a key enzyme with regard to immortalization of cancer cells and increased activity has been demonstrated in various human malignant neoplasms. Since little is known of its role in pancreatic cancers, we investigated changes in telomerase activity in human pancreatic duct adenocar‐cinomas and compared the frequency of increased telomerase activity with the presence of K‐ras gene mutations. The samples were obtained from 38 pancreatic duct adenocarcinomas and 7 tumor surrounding tissues at surgical resection. Telomerase activity was examined by telomeric repeat amplification protocol assay and terminal restriction fragment (TRF) length was examined by Southern analysis. K‐ras mutation was examined by means of polymerase chain reaction‐single strand conformation polymorphism analysis. Among 38 pancreatic carcinomas, 32 (84%) exhibited increased telomerase activities with no apparent relation to the histological type of tumor, tumor size, regional lymphnode involvement and distant metastasis or clinical stage. In tissue surrounding the tumor, telomerase activity was not detected. TRF length tended to be reduced in pancreatic carcinomas. Mutations of K‐ras gene were found in 24 out of the 38 (63%) cases. Among the 38 cases, 14 showed increased telomerase activity without K‐ras mutation and 4 cases showed K‐ras mutation without telomerase activity. These results suggest that increased telomerase activity might be a sensitive genetic diagnostic marker and could be a target for future therapy of pancreatic duct carcinomas.

Adenoma-Carcinoma Sequence of Colorectum

One hundred and fifty colorectal adenomas were investigated in order to detect the presence of K-ras gene mutation. The adenomas were classified according to the severity of the histological lesion (mild, moderate, or severe dysplasia and carcinomatous transformation) and to the degree of aneuploidy. K-ras mutation was found in 30.8% of cases, mostly consisting of a point mutation of codon 12. K-ras mutation was more frequently found in adenomas > 1 cm and in the villous type. No correlation was otherwise demonstrable with the ploidy pattern of the lesion.

K-ras gene mutations: an unfavorable prognostic marker in stage I lung adenocarcinoma.

Activation of K-ras gene by point mutations, a common finding in lung adenocarcinomas, has been suggested to decrease patient survival. We investigated 109 lung adenocarcinomas, mostly small, peripheral, stage I tumours (81/109) for presence of K-ras gene mutations at codons 12 and 13. Mutations were detected by denaturing gradient gel electrophoresis analysis of specific sequences amplified by polymerase chain reaction from DNA extracted from archival pathological material. Thirty-three of 109 (30.3%) tumours showed mutations at codon 12 (28/33, 84.8%) or 13 (5/33, 15.2%) of the gene. Mutations and type of nucleotide substitutions were differently distributed among cytological subtypes, being more prevalent among less differentiated (G2 and G3) tumours and among bronchial than bronchiolo-alveolar type adenocarcinomas. Survival analysis showed an adverse effect of K-ras mutation on survival, restricted to stage I tumours. Median survival for 81 stage I patients was 30 months for non-mutated tumours versus 20 months for mutated tumours (p = 0.016). Multivariate analysis showed that age of patient (p = 0.001) and K-ras mutation status (p = 0.04) were the only independent factors influencing survival significantly. These data strengthen the hypothesis that K-ras gene mutations may be useful in identifying a subgroup of patients with poor outcome.

K‐ras Gene Mutation in Early Ductal Lesions Induced in a Rapid Production Model for Pancreatic Carcinomas in Syrian Hamsters

The presence of K‐ras gene mutation was examined in experimentally induced preneoplastic pancreatic ductal lesions. Syrian hamsters received 70 mg/kg of N‐nitrosobis(2‐oxopropyl)amine (BOP) followed by repeated exposure to an augmentation pressure regimen consisting of choline‐deficient diet combined with dl‐ethionine and l‐methionine and administration of 20 mg/kg BOP. After two augmentation pressure cycles, pancreatic ductal cell hyperplasias appeared and after three cycles, atypical hyperplasias of pancreatic ductal cells and intraductal carcinomas developed. K‐ras mutations were detected by single‐strand conformation polymorphism analysis of polymerase chain reaction products and nucleotide sequencing. The results showed that K‐ras mutation had occurred in one of 9 simple hyperplasias of pancreatic ductal epithelium, in 5 of 9 atypical hyperplasias, and in 4 of 8 intraductal carcinomas. The findings thus suggested that K‐ras is activated in association with very early stage malignant transformation of pancreatic ductal cells in hamsters.