KRAS Mutation Testing Research Articles

Optimising primary molecular profiling in non-small cell lung cancer.

Molecular profiling of NSCLC is essential for optimising treatment decisions, but often incomplete. We assessed the efficacy of protocolised molecular profiling in the current standard-of-care (SoC) in a prospective observational study in the Netherlands and measured the effect of providing standardised diagnostic procedures. We also explored the potential of plasma-based molecular profiling in the primary diagnostic setting. This multi-centre prospective study was designed to explore the performance of current clinical practice during the run-in phase using local SoC tissue profiling procedures. The subsequent phase was designed to investigate the extent to which comprehensive molecular profiling (CMP) can be maximized by protocolising tumour profiling. Successful molecular profiling was defined as completion of at least EGFR and ALK testing. Additionally, PD-L1 tumour proportions scores were explored. Lastly, the additional value of centralised plasma-based testing for EGFR and KRAS mutations using droplet digital PCR was evaluated. Total accrual was 878 patients, 22.0% had squamous cell carcinoma and 78.0% had non-squamous NSCLC. Stage I-III was seen in 54.0%, stage IV in 46.0%. Profiling of EGFR and ALK was performed in 69.9% of 136 patients included in the run-in phase, significantly more than real-world data estimates of 55% (p<0.001). Protocolised molecular profiling increased the rate to 77.0% (p = 0.049). EGFR and ALK profiling rates increased from 77.9% to 82.1% in non-squamous NSCLC and from 43.8% to 57.5% in squamous NSCLC. Plasma-based testing was feasible in 98.4% and identified oncogenic driver mutations in 7.1% of patients for whom tissue profiling was unfeasible. This study shows a high success rate of tissue-based molecular profiling that was significantly improved by a protocolised approach. Tissue-based profiling remains unfeasible for a substantial proportion of patients. Combined analysis of tumour tissue and circulating tumour DNA is a promising approach to allow adequate molecular profiling of more patients.

Molecular Spectrum of K-RAS Mutations in Colorectal Cancer Patients in Peshawar, Pakistan

Background: The global incidence of colorectal cancer (CRC) has surged, presenting a significant health challenge with an annual occurrence of 1.7 million cases. The American Cancer Society reports that KRAS and BRAF mutations contribute to 20-50% of CRC cases. This study addresses the gap in data on KRAS mutations in CRC patients in Peshawar, Pakistan. Objective: To determine the prevalence and types of KRAS mutations in colorectal cancer patients in Peshawar, Pakistan. Methods: This retrospective, cross-sectional study was conducted at the Nuclear Medicine, Oncology, and Radiotherapy Institute (NORI) Hospital in Islamabad from April to November 2022. DNA was extracted from formalin-fixed, paraffin-embedded tissue blocks of 58 CRC patients, regardless of age and gender, following informed verbal consent. KRAS mutation testing was performed using the Cobas Z480 Real-time thermal cycler. Results: Among the 58 CRC patients, 34 (58.6%) were females, and 24 (41.4%) were males. The highest CRC incidence (36.2%) was observed in the 11-25 years age group. KRAS mutations at codons 12 and 13 were found in 18% of cases, with all isolates carrying the G12D mutation. Kaplan-Meier analysis revealed a lower survival probability for patients with codon 12 mutations compared to those with codon 13 mutations. Conclusion: The study highlights the need for broader research on KRAS mutations across diverse ethnicities and geographical regions in Pakistan to better understand CRC prevalence and improve patient outcomes.

THE EFFECT OF PRIMARY LOCALIZATION OF COLORECTAL CANCER&#x0D; ON KRAS STATUS AND ITS PROGNOSTIC VALUE

Relevance: Colorectal cancer (CRC), arising from the right-sided or left-sided colon, is a separate clinical and pathological unit. The status&#x0D; of KRAS and its predictive value in CRC remain controversial.&#x0D; The study aimed to explore the effect of primary tumor localization on KRAS gene status in CRC.&#x0D; Methods: The study included 60 patients with colon and rectal cancer. The KRAS mutation test was performed on paraffin-coated tumor samples&#x0D; using PCR methods. Colon cancer was divided into right-sided colon cancer (RSCC) and left-sided colon cancer (LSCC).&#x0D; Results: KRAS mutation was found much more often in rectal cancer (RC) and sigmoid colon (SC) (p=0.413) than in tumors in other parts&#x0D; of the colon. A combined analysis of our data and previously published data showed that KRAS mutation was more common in PSTC, especially&#x0D; in the area of the hepatic bend of the colon than in LSTC (p=0.120). The association of the KRAS mutation with the patient’s age (p&lt;0.012) and&#x0D; the duration of hospitalization (p&lt;0.001) was established.&#x0D; Conclusion: Our study revealed no significant difference in the KRAS status between colon cancer and rectal cancer. However, KRAS&#x0D; mutation was much more common in RSCC compared to LSCC. Patients with RSCC with mutated KRAS also had a worse prognosis and&#x0D; required longer hospitalization compared to wild-type KRAS. However, patients with LSCC did not demonstrate a similar effect.

Abstract 2547: KRAS Q61 mutations in patients with gastrointestinal malignancies and association with real-world clinical outcomes

Abstract Introduction: Gene-wide KRAS mutation has been associated with worse outcomes in multiple malignancies with newer data suggesting differential impact based on specific allele. Mutation at codon Q61 is relatively infrequent with clinical significance not well understood. Here we aim to investigate the clinical significance of KRASQ61 mutation in gastrointestinal (GI) malignancies. Methods: The Foundry software platform was used to retrospectively query electronic health records to identify patients diagnosed with colorectal (CRC), pancreatic (PDAC), appendiceal (AA), cholangiocarcinoma (CC) and gastroesophageal carcinoma who underwent clinical testing for KRAS mutations in our institution between 2002-2023; clinical, molecular, and overall survival (OS) data were collected. Results: KRAS mutation was tested in 9,088 patients with CRC, PDAC, CC, AA, and gastroesophageal carcinoma. Incidence of KRAS mutation was 47% (n= 3,181) for patient with CRC, 82% for PDAC (n= 579), 16% for CC (n= 76), 51% for AA (n= 236), and 7% for gastroesophageal carcinoma (n= 43). KRASQ61 mutation was in 5% (n=218) of patients with KRAS mutation (n= 4,115). Overall frequency of KRASQ61 was 2% (n= 156) for CRC, 5% (n= 36) for PDAC, 3% (n= 12) for CC, 2% (n= 10) for AA and 1% (n= 4) for gastroesophageal carcinoma. KRASQ61 fraction of KRAS mutations was 5% for CRC, 6% for PDAC, 16% for CC, 4% for AA, 9% for gastroesophageal carcinoma. KRASQ61H was the most frequent KRASQ61 mutation among all tumor types, 57%, 61%, 60%, 50% out of KRASQ61 for CRC, PDAC, AA, and gastroesophageal carcinoma respectively; followed by KRASQ61L (20%) for CRC, but KRASQ61R for PDAC (25%), AA (20%), and gastroesophageal (25%); Patients with CC showed exclusively KRASQ61H mutations. Compared to patients with KRAS wildtype, patients with KRASQ61 mutations had worse OS in PDAC (median OS=20 vs 37 months, HR=1.9, 95%CI=1.2-3, p=0.006), while (55 vs 63 months, HR=1.2, 95%CI=0.98-1.5, p=0.076) for CRC, (29 vs 25 months, HR=1.3, 95%CI=0.64-2.6, p=0.47) for CC, and (33 vs 52 months, HR=1.1, 95%CI=0.5-2.6, p=0.75) for AA. Compared to other KRAS mutations, KRASQ61 median OS was (55 vs 53 months, HR=1, 95%CI=0.81-1.3, p=0.96) for patients with CRC, (20 vs 26 months, HR=1.4, 95%CI=0.91-2.1, p=0.1) for PDAC, (25 vs 28 months, HR=1.1, 95%CI=0.54-2.5, p=0.72) for CC, (33 vs 78 months, HR=1.6, 95%CI=0.72-3.7, p=0.24) for AA. Conclusion: KRASQ61 mutations frequency varied from 1% to 5% across different GI malignancies, with highest frequency in PDAC and CC. KRASQ61 mutations had worse OS in patients with PDAC which may suggest different co-mutations rather than specific KRASQ61 activity difference. Further allele specific analysis of KRASQ61 and co-mutations landscape is underway. Citation Format: Mahmoud Yousef, Abdelrahman Yousef, Saikat Chowdhury, Mohammad Mahdi Fanaeian, Mark Knafl, Paul M. Roy, Ashwathy Pillai, Mohammad Zeineddine, Fadl Zeineddine, Jennifer Peterson, Brandon G. Smaglo, Robert A. Wolff, Shubham Pant, Michael Sangmin Lee, Jason A. Willis, Michael James Overman, Ethan Bernard Ludmir, Mark W. Hurd, John Paul Shen, Dan Zhao. KRAS Q61 mutations in patients with gastrointestinal malignancies and association with real-world clinical outcomes [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2547.

KRAS Mutation Status in Colorectal Epithelial Tumors of Colorectal Cancer

Introduction: Colorectal cancer (CRC) is one of the commonest malignancies in industrialized nations with lower incidence in Asia and Africa. Majority of CRCs are non-hypermutated. KRAS is one of the commonest mutated genes in CRC patients. Given the KRAS mutated CRCs are resistant to EGFR targeted chemotherapy, expanded KRAS mutation testing is recommended before starting chemotherapy. The aim of this study was to study the genetic variation of KRAS in group of CRC cancer patients referred to a teaching hospital in Kolkata, India.Methods: Out of 15 cases of colorectal cancer studied, 2 specimens were right hemicolectomies for clinically diagnosed colon carcinomas and 13 specimens were biopsies of colonoscopy done for anaemia, changed bowel habit, occult bleeding. Formalin fixed paraffin embedded (FFPE) tissue sections, stained by routine Hematoxylin and Eosin were examined microscopically. The DNA was extracted from FFPE tissue with Qiagen kit. KRAS Mutation analysis was done by TheraScreen – KRAS Mutation Kit.Results: The age of patients ranged from 28 to 64 years. Nine were male and remaining 6 were female. histopathological examination revealed 10 adenomas and 5 adenocarcinomas. One adenoma, tubulovillous with high grade dysplasia featured positive KRAS mutation (Gly12Asp). Three out of 4 adenocarcinomas with positive KRAS mutation, one showed Gly12Ala and 2 showed Gly12Asp. Conclusion: The frequency of KRAS mutations was very low in the studied sample.

Echoendoscopic ultrasound pancreatic adenocarcinoma diagnosis and theranostic approach: should KRAS mutation research be recommended in everyday practice?

The impact of KRAS mutation testing on pancreatic ductal adenocarcinoma (PDAC) samples by endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) for reducing the need to repeat EUS-FNA has been demonstrated. Such testing however is not part of standard practice for endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB). We aim to analyse the proportion of non-contributive samples by EUS-FNB and to evaluate the impact of KRAS mutation testing on the diagnosis, theranostics and survival. In this retrospective study, the impact on diagnosis and survival of KRAS testing for contributive and non-contributive samples by EUS-FNB was analysed. The EUS-FNB samples, combined with KRAS testing using the Idylla® technique on liquid-based cytology from patients with PDAC between February 2019 and May 2023, were retrospectively reviewed. The cytology results were classified according to the guidelines of the World Health Organization System for Reporting Pancreaticobiliary Cytopathology (WHOSRPC). A total of 85 EUS-FNB specimens were reviewed. In all, 25 EUS-FNB samples did not lead to a formal diagnosis of PDAC according to the WHOSRPC (30.2%). Out of these 25, 11 (44%) could have been considered positive for a PDAC diagnosis thanks to the KRAS mutation test without carrying out further diagnosis procedures. The sensitivity of KRAS mutation testing using the Idylla technique was 98.6%. According to the available data, survival rates were not statistically different depending on the type of mutation. KRAS mutation testing on liquid-based cytology using the Idylla or equivalent technique, combined with the PDAC EUS-FNB sample, should become a standard for diagnosis to avoid delaying treatment by doing another biopsy. Furthermore, knowledge of the KRAS status from treatment initiation could be used to isolate mutations requiring targeted treatments or inclusion in clinical research trials, especially for wild-type KRAS PDAC.

Development and characterization of anti-G12V mutated K-Ras monoclonal antibodies using hybridoma technology

Background. Kirsten rat sarcoma oncogene, KRAS, is a gene that encodes for K-Ras protein, a membrane-anchored protein which is involved in intracellular signal transduction. Cells harbouring KRAS mutations have been reported to progress toward cancer development and several studies have suggested the importance of KRAS mutational screening prior to cancer treatment. However, currently available diagnostic methods are costly, time consuming and laborious. Thus, monoclonal antibodies are proposed as an alternative in K-Ras mutational testing. Objective. This study aims to generate and characterise anti-K-Ras monoclonal antibodies based on their specificity and sensitivity towards G12V-mutated K-Ras proteins, which is one of the most commonly mutated KRAS isoforms. Methods. Mice were first immunised with G12V-mutated K-Ras peptides and spleens were harvested. Hybridoma cells which secreted K-Ras-specific antibodies were generated by fusing splenocytes with X63-Ag 8.6539 myeloma cells. Hybridoma polyclonal wells secreting G12V-mutated K-Ras antibodies were subcloned into a single clone producing monoclonal antibodies. The specificity and sensitivity of monoclonal antibodies were evaluated by ELISA and the reactivity of monoclonal antibodies were tested using immunoblotting and immunocytochemistry. Results. The cross-reactivity results indicated that anti-G12V monoclonal antibodies developed in this study is highly specific to G12V mimotopes with a cross-reactivity of 4.2-16.7% towards wild-type and other mutated K-Ras isoforms. The limit of detection of this monoclonal antibody was determined as 3.28 μg/mL. It was also found to be reactive in immunocytochemical assays and native G12V-mutated K-Ras in immunoblotting. Conclusion. A highly specific and sensitive monoclonal antibody was successfully developed, characterised and applied to several assays such as indirect ELISA, Western Blot and immunocytochemistry. These data indicate the potential for this anti-G12V KRAS monoclonal antibody to be further developed for use in various research, diagnostic and therapeutic applications.

A rare case of esophageal metastasis from signet-ring cell carcinoma of the cecum

BackgroundMetastatic esophageal cancer is rare. Its common primary lesions include lung cancer and breast cancer. Metastatic esophageal cancer originating from colorectal cancer is rarer.Case presentationA 79-year-old woman visited our hospital because of lower abdominal discomfort. She was endoscopically diagnosed with type 0–IIa + IIc cancer of the cecum, and biopsy of the lesion showed signet-ring cell carcinoma. With a preoperative clinical staging of cStage I (cT2, cN0, cM0), the patient underwent laparoscopic ileocecal resection with D3 lymphadenectomy. Histopathological examination of the resected specimens revealed signet-ring cell carcinoma [type 4, pT4a, pN3 (No. 203), M0, pRM1, stage IIIc, R1]. Despite radial margin positivity, the patient refused resection of the residual tumor and received oral tegafur and uracil. KRAS mutation test showed KRAS wild-type colon cancer, but she refused anti-epidermal growth factor receptor therapy. One year after surgery, her blood carcinoembryonic antigen concentration elevated. Colonoscopy showed anastomotic recurrence and biopsy of the lesion showed signet-ring cell carcinoma. Upper gastrointestinal endoscopy showed multiple longitudinal submucosal tumors with erosions on their surfaces in the esophagus. Tumor biopsy revealed signet-ring cell carcinoma. Immunohistochemistry showed that the histological type of the esophageal tumors was the same as that of the primary colon cancer. Based on these findings, the esophageal tumors were diagnosed with metastasis from signet-ring cell carcinoma of the cecum. The oral chemotherapy was replaced with FOLFOX plus bevacizumab. However, the patient’s condition required treatment discontinuation, and she died of cancer progression 1 year and 5 months after surgery.ConclusionsTo our knowledge, this is the first case report on metastatic esophageal cancer from signet-ring cell carcinoma of the cecum. Esophagoscopy showed multiple longitudinal submucosal tumors, which is similar to an endoscopic finding of intramural metastasis from primary esophageal cancer. We consider that the multiple longitudinal submucosal tumors are a notable feature of our case. When metastatic esophageal cancer is suspected, clinicians, endoscopists, and pathologists should consider signet-ring cell carcinoma of the colon as one of potential primary lesions. This consideration could lead the specialists to appropriate examinations and treatments, thereby improving clinical outcomes in patients with the metastasis.

Adequacy of cytology and small biopsy samples obtained with rapid onsite evaluation (ROSE) for predictive biomarker testing in non-small cell lung cancer

Complete biomarker workup of non-small cell lung cancer (NSCLC) specimens is essential for appropriate and timely clinical management decisions. This can be challenging to achieve from small cytology and histology specimens, with increasing numbers of molecular and immunohistochemical biomarkers required. We conducted a 5 year retrospective audit of cases at our institution to assess the diagnostic and biomarker testing adequacy rates, particularly those specimens obtained with rapid onsite evaluation (ROSE), performed by a cytopathologist and a cytology scientist or pathology trainee, including all endobronchial ultrasound guided transbronchial needle aspirations (EBUS-TBNA), CT guided lung fine needle aspirations (FNA) and CT guided lung core biopsies. A total of 5,354 cases were identified, of which 92.2% had sufficient material for diagnosis. Of the 1506 cases identified with a recorded diagnosis of lung adenocarcinoma or NSCLC, not otherwise specified, 1001 (66.5%) had biomarker testing requested. Sufficient material was available in 89.5% of cases for a complete biomarker workup which included EGFR and KRAS mutational testing (all cases), ALK, ROS1 and PD-L1 immunohistochemistry (all cases), and ALK and ROS1 FISH (as required). For EGFR and KRAS mutational testing across both cytology and histology specimens, 99% of cases were sufficient. Of the samples in which a complete biomarker workup was unable to be performed, approximately half were only insufficient due to inadequate numbers of tumour cells for PD-L1 immunohistochemistry. Excluding PD-L1 IHC, 952 (95.1%) of samples obtained with ROSE were sufficient for the remainder of the testing requirements. Next generation sequencing using a 33 gene custom AmpliSeq panel was achieved in up to 72% of cases. In conclusion, small cytology and histology specimens obtained with ROSE are suitable for predictive biomarker testing in NSCLC, although attention needs to be paid to obtaining sufficient cells (>100) for PD-L1 immunohistochemistry.

Different prognostic values of KRAS exon 2 submutations and BRAF V600E mutation in microsatellite stable (MSS) and unstable (MSI) stage III colon cancer: an ACCENT/IDEA pooled analysis of seven trials

The prognostic value of KRAS and BRAFV600E mutations in stage III colon cancer (CC) remains controversial and has never been clearly analyzed in patients with microsatellite instability-high (MSI-H) tumors due to sample size limitations. Data are also lacking for KRAS submutations and prognosis. We examined clinicopathological variables and prognosis in patients with surgically resected stage III CC who participated in seven clinical trials from the ACCENT/IDEA databases. Associations between KRAS exon 2 and BRAFV600E mutations and time to recurrence (TTR), overall survival (OS), and survival after recurrence (SAR) were assessed using a Cox model. We also analyzed the prognostic value of KRAS exon 2 submutations. Among 8460 patients, 11.4% had MSI-H status. In the MSI-H group, BRAFV600E, KRAS exon 2 mutants, and double-wild-type statuses were detected in 40.6%, 18.1%, and 41.3%, respectively, whereas and in the microsatellite stable (MSS) group, these were detected in 7.7%, 38.6%, and 53.8%, respectively. In the MSS group, 5-year TTR rates of 61.8%, 66.3%, and 72.9% were observed among patients with BRAFV600E, KRAS exon 2 mutants, and those who were DWT, respectively [adjusted hazard ratio (HR)= 1.58 and 1.31, both P < 0.001]. In the MSI-H group, 5-year TTR rates did not differ significantly among the mutated subgroups. Similar results were found for OS. However, survival after relapse was significantly shorter in the KRAS exon 2- and BRAFV600E-mutated patients in both MSS (adjusted HR= 2.06 and 1.15; both P < 0.05) and MSI-H (adjusted HR= 1.99 and 1.81; both P < 0.05) groups. In the MSS group, KRAS exon 2 mutations were associated with TTR, but only p.G12C, p.G12D, and p.G13D were associated with poor outcomes after disease recurrence. Testing for both KRAS and BRAFV600E mutations in stage III patients should be considered as they can better define individual patient prognosis, and may also enable patient selection for (neo)adjuvant trials dedicated to specific molecular subtypes with poor prognosis.

Construction of prediction model for KRAS mutation status of colorectal cancer based on CT radiomics

BackgroundIn this study, we used computed tomography (CT)-based radiomics signatures to predict the mutation status of KRAS in patients with colorectal cancer (CRC) and to identify the phase of radiomics signature with the most robust and high performance from triphasic enhanced CT.MethodsThis study involved 447 patients who underwent KRAS mutation testing and preoperative triphasic enhanced CT. They were categorized into training (n = 313) and validation cohorts (n = 134) in a 7:3 ratio. Radiomics features were extracted using triphasic enhanced CT imaging. The Boruta algorithm was used to retain the features closely associated with KRAS mutations. The Random Forest (RF) algorithm was used to develop radiomics, clinical, and combined clinical–radiomics models for KRAS mutations. The receiver operating characteristic curve, calibration curve, and decision curve were used to evaluate the predictive performance and clinical usefulness of each model.ResultsAge, CEA level, and clinical T stage were independent predictors of KRAS mutation status. After rigorous feature screening, four arterial phase (AP), three venous phase (VP), and seven delayed phase (DP) radiomics features were retained as the final signatures for predicting KRAS mutations. The DP models showed superior predictive performance compared to AP or VP models. The clinical–radiomics fusion model showed excellent performance, with an AUC, sensitivity, and specificity of 0.772, 0.792, and 0.646 in the training cohort, and 0.755, 0.724, and 0.684 in the validation cohort, respectively. The decision curve showed that the clinical–radiomics fusion model had more clinical practicality than the single clinical or radiomics model in predicting KRAS mutation status.ConclusionThe clinical–radiomics fusion model, which combines the clinical and DP radiomics model, has the best predictive performance for predicting the mutation status of KRAS in CRC, and the constructed model has been effectively verified by an internal validation cohort.

KRAS mutation in primary ovarian serous borderline tumors correlates with tumor recurrence.

Oncogenic activation of the mitogen-activated protein kinase (MAPK) pathway due to KRAS or BRAF gain-of-function mutation is frequently found in ovarian serous borderline tumor (SBT) and their extraovarian implants. We investigated mutational status of KRAS and BRAF of the primary ovarian SBTs that had a high stage presentation in correlation with clinical outcome. Among 39 consecutive primary SBTs with either invasive implants (20 cases) or non-invasive implants (19 cases), KRAS and BRAF mutational analysis was informative in 34 cases. Sixteen cases (47%) harbored a KRAS mutation, while 5 cases (15%) had a BRAF V600E mutation. High-stage disease (IIIC) was seen in 31% (5/16) of patients with a KRAS mutation and 39% (7/18) of patients without a KRAS mutation (p = 0.64). KRAS mutations were present in 9/16 (56%) tumors with invasive implants/LGSC versus 7/18 (39%) tumors with non-invasive implants (p = 0.31). BRAF mutation was seen in 5 cases with non-invasive implants. Tumor recurrence was seen in 31% (5/16) of patients with a KRAS mutation, compared to 6% (1/18) of patients without a KRAS mutation (p = 0.04). A KRAS mutation predicted an adverse disease-free survival (31% survival at 160months) compared to those with wild-type KRAS (94% at 160months; log-rank test, p = 0.037; HR 4.47). In conclusion, KRAS mutation in primary ovarian SBTs is significantly associated with a worse disease-free survival, independent of the high tumor stage or histological subtypes of extraovarian implant. KRAS mutation testing of primary ovarian SBT may servce as a useful biomarker for tumor recurrence.

Abstract 5399: Deep learning-based ensemble model using H&amp;E images for the prediction of KRAS G12C mutations in non-small cell lung cancer

Abstract Background: As the KRAS G12C mutation became targetable in non-small cell lung cancer (NSCLC), tissue based KRAS mutation test is now an essential practice for the treatment decision. Recently, predicting KRAS mutations using deep-learning models with H&amp;E images to potentially increase the pre-test probability has been reported with modest performance. Herein, we conducted a novel approach to improve the performance of KRAS G12C prediction based on an ensemble model trained not solely on H&amp;E images, but also with multi-layered semantic content produced by a pre-trained artificial-intelligence (AI) analyzer, Lunit SCOPE IO. Methods: The Cancer Genome Atlas LUAD and LUSC (TCGA-Lung) samples were used for model development. A self-supervised vision transformer was used to extract deep features from raw H&amp;E images; and an AI-based pathology profiling analyzer extracted semantic contents such as the spatial information of tumor cells, lymphocytes, cancer epithelium, and cancer stroma. A set of classifiers was trained based on the two features, and the ensemble of these features was used to improve robustness. The final model was evaluated through cross-validation and assessed on independent NSCLC samples from Samsung Medical Center (SMC) who tested KRAS mutation by various methods including whole exome sequencing or target sequencing. Results: TCGA-Lung dataset (n = 930) includes 150 (16.1%) KRAS driver mutations, and 62 (6.7%) KRAS G12C. The best cross-validation performances of the models predicting KRAS G12C, measured by mean area-under-the-curve (AUC), were 0.768 trained by only H&amp;E images (HE-only), 0.714 by AI semantic content (AISC) with MLP classifier (AI-MLP), and 0.697 by AISC with random forest (AI-RF), respectively. An ensemble of the three models showed an increased AUC of 0.787 in TCGA-Lung by cross-validation. These models were applied to an independent SMC dataset (n = 363), including 54 (14.9%) KRAS driver mutations, and 22 (6.1%) KRAS G12C. The mean AUC to predict KRAS G12C by HE-only, AI-MLP, and AI-RF models were 0.599, 0.644, and 0.678, respectively, implying limited robustness. However, the AUC of an ensemble of the 3 models was 0.745 in the SMC dataset, showing 71.0% sensitivity and 72.7% specificity. Similar results were observed regardless of the KRAS testing method (TruSight Oncology 500 panel; n = 249; AUC 0.787, other tests; n = 114; AUC 0.720), the tissue size (surgical resection; n = 138; AUC 0.724, biopsy n = 225; AUC 0.763), and histology (excluding squamous cell carcinoma, n = 286; AUC 0.697). Conclusions: An AI-based ensemble model combining H&amp;E images with semantic contents extracted from pre-developed AI model significantly improved the accuracy and the robustness of KRAS G12C mutation prediction using H&amp;E sample in NSCLC. Citation Format: Sehhoon Park, Jongchan Park, Minuk Ma, Hyun-Ae Jung, Jong-Mu Sun, Yoon-La Choi, Jin Seok Ahn, Myung-Ju Ahn, Sanghoon Song, Gahee Park, Sukjun Kim, Huijeong Kim, Seunghwan Shin, Chan-Young Ock, Se-Hoon Lee. Deep learning-based ensemble model using H&amp;E images for the prediction of KRAS G12C mutations in non-small cell lung cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5399.

Kristen Rat Sarcoma Viral Oncogene Mutations in Colorectal Carcinomas at the University Teaching Hospital in Lusaka, Zambia

Background: The second leading cause of cancer-related deaths worldwide is colorectal cancer. With an incidence rate of 4.8 per 100,000, this is Zambia’s sixth most prevalent cancer;&#x0D; &#x0D; Methods: This laboratory-based, cross-sectional study examined the frequency of Kirsten rat sarcoma viral oncogene homolog (KRAS) mutation and its association with prognostic factors in colorectal carcinoma cases from the University Teaching Hospital-Adult Hospital (UTHs), Lusaka, Zambia;&#x0D; &#x0D; Results: Thirty (30) formalin-fixed paraffin-embedded (FFPE) samples collected between June 2017 and June 2018 were sent to the Lancet laboratories and analyzed for KRAS mutations (codons 12 and 13). One FFPE block did not meet the inclusion criteria and was excluded. The demographic and clinicopathological data were analyzed using STATA 12. Males outnumber females by 20 to nine. The average age of the patient was 45 ± 16 years. The rectum was the location of 44.8% of the tumors, with the majority being conventional adenocarcinoma (CAC) (65.6 %). All cases (100%) had advanced-stage (stages 3 and 4) disease; however, only 27.6% of patient tumors exhibited lymphovascular invasion. KRAS mutation was detected in 11 (37.9%) cases and mainly in left-sided tumors (62.5%). KRAS mutations were only detected in CAC and serrated adenocarcinoma subtypes. No significant associations were observed between the KRAS mutation status and tumor or patient’s clinical and sociodemographic factors;&#x0D; &#x0D; Conclusion: We advocate for incorporating KRAS mutation testing into the standard of care for treating colorectal cancer.

Kristen Rat Sarcoma Viral Oncogene Mutations in Colorectal Carcinomas at the University Teaching Hospital in Lusaka, Zambia

Background: The second leading cause of cancer-related deaths worldwide is colorectal cancer. With an incidence rate of 4.8 per 100,000, this is Zambia’s sixth most prevalent cancer;&#x0D; Methods: This laboratory-based, cross-sectional study examined the frequency of Kirsten rat sarcoma viral oncogene homolog (KRAS) mutation and its association with prognostic factors in colorectal carcinoma cases from the University Teaching Hospital-Adult Hospital (UTHs), Lusaka, Zambia;&#x0D; Results: Thirty (30) formalin-fixed paraffin-embedded (FFPE) samples collected between June 2017 and June 2018 were sent to the Lancet laboratories and analyzed for KRAS mutations (codons 12 and 13). One FFPE block did not meet the inclusion criteria and was excluded. The demographic and clinicopathological data were analyzed using STATA 12. Males outnumber females by 20 to nine. The average age of the patient was 45 ± 16 years. The rectum was the location of 44.8% of the tumors, with the majority being conventional adenocarcinoma (CAC) (65.6 %). All cases (100%) had advanced-stage (stages 3 and 4) disease; however, only 27.6% of patient tumors exhibited lymphovascular invasion. KRAS mutation was detected in 11 (37.9%) cases and mainly in left-sided tumors (62.5%). KRAS mutations were only detected in CAC and serrated adenocarcinoma subtypes. No significant associations were observed between the KRAS mutation status and tumor or patient’s clinical and sociodemographic factors; &#x0D; Conclusion: We advocate for incorporating KRAS mutation testing into the standard of care for treating colorectal cancer.

Evaluation of the KRAS mutations in colorectal and pancreatic cancer patients

The RAS gene family is among the most studied and best characterized of the known cancer related genes. Of the three human RAS isoforms, KRAS is the most frequently altered gene, with mutations occurring in 17%–25% of all cancers. KRAS mutations are one of the most dominant mutations at 7% to 80% for colorectal cancer, 25% to 87% for pancreatic cancer, and 25% to 48% for lung cancer. The impact of KRAS mutations on the prognosis and survival of patients with adenocarcinoma and other types of cancer stimulates a lot of scientific research on their developmental mechanisms. To further develop a protocol for the treatment of mutant KRAS cases in Kazkahstan we study KRAS mutations status in Kazakhstani colorectal cancer and pancreatic patients. In this article, we review the literature on the role of KRAS mutation testing for management of patients and demonstrate preliminary data on KRAS mutation status in Kasakhstani patients with colorectal and pancreatic cancer.

KRAS Mutation Testing on Endoscopic Ultrasound-Guided Fine-Needle Aspiration Samples Improves the Diagnostic Accuracy of Pancreatic Cancer.

Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) cytology was one of the investigations for pancreatic masses. While the specificity approached 100%, its sensitivity remained low because of high rate of indeterminate and false-negative results. Meanwhile, KRAS gene was frequently mutated in up to 90% of pancreatic ductal adenocarcinoma and its precursor lesions. This study aimed to determine whether KRAS mutation analysis could improve the diagnostic sensitivity in EUS-FNA samples for pancreatic adenocarcinoma. The EUS-FNA samples from patients with a pancreatic mass obtained between January 2016 and December 2017 were reviewed retrospectively. The cytology results were classified as malignant, suspicious for malignancy, atypical, negative for malignancy, and nondiagnostic. KRAS mutation testing was performed using polymerase chain reaction followed by Sanger sequencing. A total of 126 EUS-FNA specimens were reviewed. The overall sensitivity and specificity by cytology alone were 29% and 100%, respectively. When KRAS mutation testing was performed in cases with indeterminate and negative cytology, the sensitivity increased to 74.2%, and the specificity remained at 100%. KRAS mutation analysis, especially when performed in cytologically indeterminate cases, improves the diagnostic accuracy for pancreatic ductal adenocarcinoma. This may reduce the need to repeat invasive EUS-FNA for diagnosis.

Practical Implications of KRAS Mutation Status and Sidedness of Primary Tumour in Patients with Colorectal Cancer and Synchronous Liver Metastases: A Subset Analysis of the CoSMIC Study.

Simple SummaryPatients presenting with liver metastases at the time of diagnosis of their colorectal cancer (termed ‘synchronous disease’) have a worse outcome than those whose disease is limited to the primary bowel tumour. There is evidence to show that patients with tumours on the right side of the colon have worse survival. Furthermore, mutations in the KRAS gene have also been shown to adversely affect outcome. This study explores the association between the side of the primary colorectal tumour in patients with synchronous disease and mutations in the KRAS gene on survival. We analyse a specific cohort of patients from the previously published CoSMIC study who presented with colorectal cancer and synchronous liver metastases and who had their colorectal tumour analysed for KRAS mutations. We find that for this cohort, neither mutations in the KRAS gene nor the side of the colon tumour influenced survival.Patients with colorectal cancer presenting with synchronous liver metastases have less favourable outcomes than those with primary-only disease. There is evidence of different genetic mutational signatures according to the sidedness of the primary tumour. KRAS mutations are key driver mutations in colorectal cancer progression. This post hoc analysis of the previously reported CoSMIC inception cohort explores the association between primary tumour sidedness and KRAS mutational status on the outcome of patients with colorectal cancer and synchronous liver metastases. Patients diagnosed with synchronous disease were recruited between April 2014 and March 2017 and, after exclusions, 83 patients undergoing colorectal primary KRAS mutation testing constituted the final study population. Data were collected prospectively on demographic profiles, treatment, and outcomes. Twenty-one patients (25%) had right-sided tumours and 62 (75%) had left-sided tumours, with 46 (55%) and 37 (45%) exhibiting wildtype and mutated KRAS, respectively. There was no difference in distribution of liver metastases by KRAS status (unilobar vs. bi-lobar; p = 0.58; Fisher’s Exact test) and no difference in 5-year survival according to KRAS mutation status (Log-rank test, p = 0.82) or tumour sidedness (p = 0.16). In summary, in this cohort of patients with colorectal cancer and synchronous liver metastases, neither KRAS mutation status nor tumour sidedness influenced survival.

Colorectal cancers with a residual adenoma component: Clinicopathologic features and KRAS mutation.

Background/AimColorectal cancer is well known for its “adenoma-carcinoma” sequential carcinogenesis. Some colorectal cancers demonstrate a residual adenoma component during progression from adenoma to invasive carcinoma. However, the clinicopathological significance of residual adenoma component remains unclear. In this study, we aimed to investigate the clinicopathologic and molecular characteristics including the KRAS mutation in colorectal cancers containing a residual adenoma component.Materials and methodsIn this study, 498 surgically resected colorectal cancer patients were enrolled. Their detailed clinicopathologic features and results of molecular study including KRAS mutation test and microsatellite instability were analyzed.ResultsA residual adenoma component was identified in 42 (8.4%) patients with colorectal cancer. The presence of a residual adenoma component was associated with a high frequency of the KRAS mutation (65%, p = 0.031) as well as indolent clinicopathological features, including polypoid gross type (p < 0.001), well-differentiated histology (p < 0.001), low pT (p < 0.001) and pN stage (p = 0.003), absence of vascular invasion (p = 0.005), and a better progression-free prognosis (p = 0.029). The cases with an adenoma component had a 35.7% discordance rate on the KRAS mutation tests in their adenoma and carcinoma regions.ConclusionIn conclusion, colorectal cancer with a residual adenoma component showed indolent clinicopathologic features and frequent KRAS mutations. Due to the discordance in the incidence of the KRAS mutation between the adenoma and carcinoma components, the adenoma component should be documented in the pathology report, and care should be taken not to include the adenoma component when collecting samples for molecular testing.

922P Automated and rapid KRAS mutation testing in non-small cell lung cancer

Detecting KRAS mutations in tumor samples can be challenging in low-middle-income countries due to limited access to molecular biology laboratories. The Idylla TM KRAS mutation test (IKMT) is an IVD, automated, and rapid qPCR assay to detect KRAS mutations, validated in colorectal cancer. We studied the concordance of the IKMT in KRAS mutation detection, compared with NGS, and performed a prospective KRAS mutation test feasibility study in samples from patients with NSCLC.