Abstract 937: Molecular analysis of KRAS exon 2 wild type colorectal cancer patients enrolled in the CAPRI clinical trial reveals high degree of tumor heterogeneity

Author(s):  
Anna Maria Rachiglio ◽  
Matilde Lambiase ◽  
Francesca Fenizia ◽  
Claudia Esposito ◽  
Cristin Roma ◽  
...  
2019 ◽  
Vol 121 (5) ◽  
pp. 378-383 ◽  
Author(s):  
Elena Elez ◽  
Carles Pericay ◽  
Manuel Valladares-Ayerbes ◽  
Inmaculada Bando ◽  
Maria Jose Safont ◽  
...  

2019 ◽  
Author(s):  
Muhammad Awidi ◽  
Nidaa Ababneh ◽  
Maha Shomaf ◽  
Feras Al Fararjeh ◽  
Laila Owaidi ◽  
...  

Abstract Background A constitutively active RAS protein in the absence of stimulation of the epidermal growth factor receptor (EGFR) is the result of mutations in KRAS and NRAS genes. Mutations in the KRAS exon 2 and outside exon 2 have been found to predict the resistance to anti-EGFR monoclonal therapy. A substantial proportion of metastatic colorectal cancer cases (mCRC) exhibit RAS mutations outside KRAS exon 2, particularly in KRAS exon 3 and 4 and NRAS exons 2, 3. No data about RAS mutations outside KRAS exon 2 are available for Jordanian patients with mCRC. We aim to study the molecular spectrum, frequency, and distribution pattern of KRAS and NRAS mutations in Jordanian patients with mCRC. Methods A cohort of 190 Jordanian metastatic colorectal cancer patients were enrolled in the trial. We detected mutations in exon 2 of the KRAS and NRAS gene as well as mutations outside of exon 2 using the StripAssay technique. The KRAS StripAssay covered 29 mutations and 22 NRAS mutations. Results Mutations were observed in 92 (48.42%) cases, and KRAS exon 2 accounted for 76 cases (83.69%). KRAS G12D was the most common mutation, occurring in 18 cases, followed by KRAS G12A in 16 cases, and G12T in 13 cases. Mutations outside of KRAS exon 2 represented 16.3% of the mutated cases. Among those, 6 cases (6.48%) carried mutations in NRAS exon 2, 3 and 10 cases (10.87%) in KRAS exon 3 and 4. Conclusion The frequency of NRAS and KRAS mutations outside of exon 2 appears to be higher in Jordanian patients in comparison with patients from western countries. KRAS mutations outside of exon 2 should be tested routinely to identify patients who should not be treated with anti-EGFR antibodies.


2021 ◽  
pp. 172460082110171
Author(s):  
Ye Yuan ◽  
Yingting Liu ◽  
Ye Wu ◽  
Junling Zhang ◽  
Chunti Shen ◽  
...  

Background: The KRAS mutations are high-frequency somatic mutations found in colorectal cancer patients from Western and Asian countries however, with the exception of exon 2 of KRAS, other prevalence and prognostic values have not been adequately assessed in Asian patients. The aim of this study was to determine the mutation frequencies of whole exon mutations of KRAS in Chinese colorectal cancer patients and to investigate their impact on prognosis. Methods: A total of 7189 tumor tissue samples (iCohort) were subjected to next-generation sequencing for detection of KRAS mutations. All pathologic or likely pathologic mutations of KRAS were considered. In addition, clinical features and prognostic dates were collected from 145 patients at The Third Affiliated Hospital of Soochow University, China (sCohort) and used droplet digital™ polymerase chain reaction to detect KRAS mutations. Results: In the iCohort, 2706 patients (37.6%) were confirmed harboring KRAS mutations. The most frequent of these mutations were G12D (32.19%), G12V (17.96%), and G13D (17.59%). In the sCohort, 51 colorectal cancer patients (35.17%) had KRAS mutations, among which KRAS G12D (64.71%), G13D (29.41%), and G14D (3.92%) were high-frequency. The KRAS mutations were associated with shorter median overall survival than wild-type tumors (69 vs. 55 months; HR 1.80; 95% Cl 1.22, 2.64; P=0.0003). In the Cox multivariate analysis, age (HR 1.562; 95% Cl 1.10, 2.22; P=0.013), tumor differentiation (HR 0.417; 95% Cl 0.19, 0.90; P=0.026), and KRAS mutation (HR 1.897; 95% Cl 0.19, 0.90; P=0.001) remained independent predictors of shorter overall survival. Among the common KRAS mutations, G12D was significantly associated with shorter overall survival (HR 2.17; 95% Cl 1.31, 3.58; P < 0.0001) compared with KRAS wild-type patients. Conclusions: Our findings indicate that KRAS genes are frequently mutated, and over 30% harbored the KRAS G12D mutation subtype. We found that the KRAS G12D mutation is associated with inferior survival and is a biomarker of poor prognosis in Chinese patients. Our data emphasize the importance of molecular features in colorectal cancer patients, which could potentially be improved by G12D-specific related inhibitors.


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