Types Of KRAS Mutations Research Articles

Prognostic Role of Specific KRAS Mutations Detected in Aspiration and Liquid Biopsies from Patients with Pancreatic Cancer

Background/Objectives: Although the overall survival prognosis of patients in advanced stages of pancreatic ductal adenocarcinoma (PDAC) is poor, typically ranging from days to months from diagnosis, there are rare cases of patients remaining in therapy for longer periods of time. Early estimations of survival prognosis would allow rational decisions on complex therapy interventions, including radical surgery and robust systemic therapy regimens. Understandably, there is great interest in finding prognostic markers that can be used for patient stratification. We determined the role of various KRAS mutations in the prognosis of PDAC patients using biopsy samples and circulating tumor DNA. Methods: A total of 118 patients with PDAC, clinically confirmed by endoscopic ultrasound-guided fine-needle aspiration biopsy (EUS-FNB), were included in the study. DNA was extracted from cytological slides following a standard cytology evaluation to ensure adequacy (viability and quantity) and to mark the tumor cell fraction. Circulating tumor DNA (ctDNA) was extracted from plasma samples of 45 patients in stage IV of the disease. KRAS mutations in exons 12 and 13 were detected by denaturing capillary electrophoresis (DCE), revealing a minute presence of mutation-specific heteroduplexes. Kaplan–Meier survival curves were calculated for individual KRAS mutation types. Results:KRAS mutations were detected in 90% of tissue (106/118) and 44% of plasma (20/45) samples. All mutations were localized at exon 2, codon 12, with G12D (GGT > GAT) being the most frequent at 44% (47/106) and 65% (13/20), followed by other types including G12V (GGT > GTT) at 31% (33/106) and 10% (2/20), G12R (GGT > CGT) at 17% (18/106) and 10% (2/20), G12C (GGT/TGT) at 5% (5/106) and 0% (0/20) and G12S (GGT/AGT) at 1% (1/106) and 5% (1/20) in tissue and plasma samples, respectively. Two patients had two mutations simultaneously (G12V + G12S and G12D + G12S) in both types of samples (2%, 2/106 and 10%, 2/20 in tissue and plasma samples, respectively). The median survival of patients with the G12D mutation in tissues was less than half that of other patients (median survival 101 days, 95% CI: 80–600 vs. 228 days, 95% CI: 184–602), with a statistically significant overall difference in survival (p = 0.0080, log-rank test), and furthermore it was less than that of all combined patients with other mutation types (101 days, 95% CI: 80–600 vs. 210 days, 95% CI: 161–602, p = 0.0166). For plasma samples, the survival of patients with this mutation was six times shorter than that of patients without the G12D mutation (27 days, 95% CI: 8–334 vs. 161 days, 95% CI: 107–536, p = 0.0200). In contrast, patients with detected KRAS G12R in the tissue survived nearly twice as long as other patients in the aggregate (286 days, 95% CI: 70–602 vs. 162 days, 95% CI: 122–600, p = 0.0374) or patients with other KRAS mutations (286 days, 95% CI: 70–602 vs. 137 days, 95% CI: 107–600, p = 0.0257). Conclusions: Differentiation of specific KRAS mutations in EUS-FNB and ctDNA (above all, the crucial G12D and G12R) is feasible in routine management of PDAC patients and imperative for assessment of prognosis.

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.

Phase 1/2 trial of the XPO1 inhibitor selinexor in combination with docetaxel in previously treated, advanced KRAS mutant non-small cell lung cancer (NSCLC).

8597 Background: KRAS mutant NSCLC remains a therapeutic challenge. Although KRAS G12C inhibitors are now approved for cases harboring that specific mutation, their efficacy is modest and the G12C variant accounts for only 40% of KRAS mutations in NSCLC. To date, there are no approved targeted therapies for non-G12C KRAS mutant NSCLC. Selective inhibitors of nuclear export (SINE) modulate cancer cell biology by retaining certain proteins—such as tumor suppressors—within the nucleus, where they remain physiologically active. The XPO1 inhibitor selinexor demonstrated efficacyinpreclinicalNSCLC models harboring various KRAS mutations. Methods: In this 3 + 3 dose-escalation phase 1/2 trial, patients with previously treated advanced KRAS mutant NSCLC received selinexor (dosed orally weekly) plus docetaxel 75 mg/m2 IV every three weeks (NCT03095612). Prior treatment with KRAS G12C inhibitors was permitted. Results: Among 40 enrolled patients, median age was 66 years, 22 (55%) were female, and 34 (85%) were white. KRAS mutation types included G12C (28%), G12V (23%), G12D (20%), G12A (13%), G12R (5%), G13C (5%), and one case each of G12S, G13D, Q61L, and K117N. Patients had received a median of 2 prior lines of therapy (range 1-4). The maximum tolerated dose of selinexor was 60 mg PO weekly combined with docetaxel. The most common adverse events (AE) were nausea (73%, Gr ≥3 8%), fatigue (70%, Gr ≥3 5%), neutropenia (65%, Gr ≥3 60%), diarrhea (58%, Gr ≥3 10%), anorexia (50%, Gr ≥3 0%), and vomiting (45%, Gr ≥3 5%). Of 32 patients evaluable for efficacy, 7 (22%) had partial response (PR) and 18 (56%) had stable disease (SD) as best response. Median progression-free survival (PFS) was 4.1 months (95% CI, 2.9-5 months); median overall survival (OS) was 7.1 months (95% CI, 4.5-13.7 months). Clinical outcomes did not differ significantly among KRAS mutation types. However, TP53co-mutations (48%) were associated with significantly worse outcomes: disease control rate (PR + SD) 27% vs 92% ( P=0.006); median PFS 1.8 vs 7.4 months ( P<0.001); median OS 5.8 vs 17 months ( P=0.006). Additional biomarker studies are ongoing. Conclusions: Selinexor plus docetaxel is tolerated with multi-agent supportive care. The combination shows moderate efficacy across KRAS mutation types, with promising activity in TP53 wild type cases. Clinical trial information: NCT03095612 .

Next-generation sequencing in patients with lung cancer undergoing immunotherapy: Retrospective analysis.

e15071 Background: Identifying targetable oncogenic drivers and resistance mechanisms by Next-generation sequencing (NGS) is critical in Non-Small Cell Lung Cancer (NSCLC). Methods: We conducted a retrospective study at the University of Vermont Center to assess the utilization of NGS in NSCLC. We examined the medical records of NSCLC patients who received Immune Checkpoint Inhibitors (ICIs) as a first-line therapy between January 2017 and June 2022. We collected demographic data, including age, sex, ethnicity, cancer stage, NGS, mutations and survival data. Survival analysis was performed for the most common mutation by measuring the Hazard Ratio (HR) via Cox regression of different mutations compared to the whole cohort. Results: We identified 95 NSCLC patients with 52.6% males, 94.7% whites and a mean age of 63.4 years (Standard Deviation (SD): 11.34). 67.4 % received Pembrolizumab and 30.5% got Durvalumab. Most patients had stage 4 and stage 3 cancers, with 54.7% and 35.8%, respectively. Mean ECOG of 0.9 (SD: 0.7), 34% had average body mass index, and overall mortality was 41%. PD L1 expression and NGS were reported in 81% of cases. NGS was reported in 88.5% of stage 4 and 76.5% of stage 3 categories. 41.8% had a type of KRAS mutation, with KRAS p.G12C being the most common. 24.1% of cases had no mutation. The mean survival months ranged from 7.6 months in MET to 52.4 months in RET mutation. Survival analysis showed decreased mortality in EGFR mutation, as seen in Table. Conclusions: The rate of NGS testing at our rural academic center in Vermont is on the higher side of the national average NGS testing, but the turnaround time (TAT) of 28 days is suboptimal compared to NCI centers. Strategies to reduce TAT need to be implemented to get timely essential for tailoring therapies in patients with NSCLC. Further research is needed to explore the prognostic utility of mutations in NSCLC patients undergoing ICIs. [Table: see text]

Abstract 3313: Discovery of a potent, selective, and orally available small molecule for disruption of the SOS1-RAS interaction

Abstract KRAS mutations represent one of the most common genetic alterations in many cancers including non-small cell lung cancer (NSCLC), pancreatic ductal adenocarcinoma (PDAC), and colorectal cancer (CRC). While Sotorasib and Adagrasib, KRAS G12C inhibitors, have received approval, they exhibit limited responsiveness in clinical trials and are not applicable to various other KRAS mutation types. SOS1 (Son of Sevenless 1) functions as a guanine nucleotide exchange factor (GEF) on RAS, facilitating the transition of inactive GDP-bound RAS to its active GTP-bound state. In addition, SOS1 plays a pivotal role in negative feedback by actively contributing to the reactivation of ERK during treatment with inhibitors targeting the RTK/RAS/MAPK pathway. Inhibiting SOS1, which impedes the reactivation of ERK, has the potential to enhance the effectiveness of inhibitors targeting the RTK/RAS/MAPK signaling cascade and prevent the emergence of resistance mechanisms via H-RAS and N-RAS bypass pathways. Therefore, combining the inhibition of SOS1 with inhibitors targeting the RTK/RAS/MAPK pathway may enhance outcomes and mitigate relapse associated with observed resistances. Here, we present the discovery of a potent, selective, and orally bioavailable small molecule SOS1 inhibitor that effectively disrupts the interaction between SOS1 and RAS. It has demonstrated remarkable synergy effects with RTK/RAS/MAPK pathway inhibitors, significantly impeding the growth of tumors carrying KRAS or EGFR mutations in vivo. Overall, our development candidate has demonstrated significant therapeutic potential in combination with inhibitors targeting the RTK/RAS/MAPK pathway for cancers bearing activating mutations in this pathway. Citation Format: Dong Hyuk Ki, Hana Yu, Donggeon Kim, Yeejin Jeon, Seongin Jo, Joonwoo Nam, Eun-Jung Kim, Sungeun Kim, Hunmi Choi, Jieun Kim, Jihyun Yu, Sungpil Choi, Wooseok Han. Discovery of a potent, selective, and orally available small molecule for disruption of the SOS1-RAS interaction [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 3313.

Nutlin-3a induces KRAS mutant/p53 wild type lung cancer specific methuosis-like cell death that is dependent on GFPT2

BackgroundOncogenic KRAS mutation, the most frequent mutation in non-small cell lung cancer (NSCLC), is an aggressiveness risk factor and leads to the metabolic reprogramming of cancer cells by promoting glucose, glutamine, and fatty acid absorption and glycolysis. Lately, sotorasib was approved by the FDA as a first-in-class KRAS-G12C inhibitor. However, sotorasib still has a derivative barrier, which is not effective for other KRAS mutation types, except for G12C. Additionally, resistance to sotorasib is likely to develop, demanding the need for alternative therapeutic strategies.MethodsKRAS mutant, and wildtype NSCLC cells were used in vitro cell analyses. Cell viability, proliferation, and death were measured by MTT, cell counting, colony analyses, and annexin V staining for FACS. Cell tracker dyes were used to investigate cell morphology, which was examined by holotomograpy, and confocal microscopes. RNA sequencing was performed to identify key target molecule or pathway, which was confirmed by qRT-PCR, western blotting, and metabolite analyses by UHPLC-MS/MS. Zebrafish and mouse xenograft model were used for in vivo analysis.ResultsIn this study, we found that nutlin-3a, an MDM2 antagonist, inhibited the KRAS-PI3K/Akt-mTOR pathway and disrupted the fusion of both autophagosomes and macropinosomes with lysosomes. This further elucidated non-apoptotic and catastrophic macropinocytosis associated methuosis-like cell death, which was found to be dependent on GFPT2 of the hexosamine biosynthetic pathway, specifically in KRAS mutant /p53 wild type NSCLC cells.ConclusionThese results indicate the potential of nutlin-3a as an alternative agent for treating KRAS mutant/p53 wild type NSCLC cells.

Characterization of a cohort of metastatic lung cancer patients harboring KRAS mutations treated with immunotherapy: differences according to KRAS G12C vs. non-G12C.

Approximately 20% of lung adenocarcinomas harbor activating mutations at KRAS, an oncogene with the ability to alter the tumor immune microenvironment. In this retrospective study, we examined 103 patients with KRAS-mutant lung adenocarcinoma who were treated with immunotherapy-based regimens and we evaluated the clinical outcomes according to PD-L1 expression and the type of KRAS mutation. Among all patients included, 47% carried KRAS G12C mutation whereas 53% harbored KRAS non-G12C mutations. PD-L1 status was available for 77% of cases, with higher expression among KRAS G12C tumors (p = 0.01). Better overall survival and progression-free survival were observed in high PD-L1 expression tumors, regardless of KRAS mutation type. The heterogeneous nature of KRAS-mutant tumors and the presence of other co-mutations may contribute to different outcomes to immunotherapy-based strategies.

Clinical outcomes of KRAS-mutant non-small cell lung cancer under untargeted therapeutic regimes in the real world: a retrospective observational study.

Kirsten rat sarcoma viral oncogene homolog (KRAS) mutation seemingly suffered less effective therapeutic regimens in the absence of widely-accepted targeted drugs compared with other mutation types in non-small cell lung cancer (NSCLC). However, whether these non-selective therapy schedules for KRAS mutation matters is still under debate. Correspondingly, we aimed to compare the long term expectancy of indicated therapeutic regimes and further explore the optimal schemes of KRAS mutated NSCLC in the absence of targeted drugs in this retrospective study cohort. We conducted a single-center retrospective analysis among 66 patients diagnosed with KRAS-mutant advanced NSCLC from November 2018 to December 2020. These enrolled cases were divided into different subgroups in light of mutant isotypes, pathological characteristics, and therapeutic regimes to uncover indicated long-term survival benefits. Additionally, clinical outcomes of treatment schedules and interventional lines to KRAS-mutant NSCLC were described in detail. This cohort enrolled 8 patients with stage IIIB (12.1%) and 58 patients with stage IV (87.9%) with the median age 62 years, ranging from 32 to 91 years old. Genetically, G12C conducted as the most common KRAS mutation type, accounting for 30.3%. Pemetrexed combined with platinum chemotherapy seemed to be a priority (72.7%), and chemotherapy combined with immunotherapy became an alternative (15.2%) in clinic. Performing further analysis of long-term survival of patients receiving different treatment methods indicated that the median overall survival (mOS) in first-line therapy with antiangiogenesis or untreated was 13 and 12 months, respectively (P=0.79). In the first-line regimen, median survival was 17 months for patients who received combined immune checkpoint inhibitors and 12 months for those who did not (P=0.34). The mOS was 20 months for those who had used immune checkpoint inhibitors and 12 months for those who had not (P=0.11). Survival analysis results of NSCLC patients with different KRAS mutation types showed the median survival time of patients with G12C mutation type and patients without with nonG12C mutation type was 19 and 12 months, respectively (P=0.37). In the absence of KRAS targeted drugs, available treatment plans failed to benefit KRAS mutant sufferers regardless of isotypes, making the KRAS-targeted drugs urgent.

CRISPR prime editing for unconstrained correction of oncogenic KRAS variants

KRAS is the most commonly mutated RAS family gene and is a primary cause of the occurrence of several types of cancer. However, KRAS mutations have several unique and diverse molecular identities, making it difficult to find specific treatments. Here, we developed universal pegRNAs which can correct all types of G12 and G13 oncogenic KRAS mutations with CRISPR-mediated prime editors (PEs). The universal pegRNA successfully corrected 12 types of KRAS mutations, accounting for 94% of all known KRAS mutations, by up to 54.8% correction frequency in HEK293T/17 cells. We also applied the universal pegRNA to correct endogenous KRAS mutations in human cancer cells and found that G13D KRAS mutation was successfully corrected to wild-type KRAS sequences with up to 40.6% correction frequency without indel mutations. We propose prime editing with the universal pegRNA as a ‘one–to–many’ potential therapeutic strategy for KRAS oncogene variants.

Investigation into the content of red material in EUS-guided pancreatic cancer biopsies.

The red material occupying the larger portion of the acquired sample in EUS fine-needle biopsy (FNB) is seldom investigated. We aimed to evaluate the composition of the red material. Patients with a solid pancreatic mass who received EUS FNB from September 2020 to June 2021 were enrolled. The white or yellowish content with apparent bulk (white material) and the rest of pasta-like red content (red material) were separated immediately after puncture. Needle passes proceeded until 2 specimens with >4mm of white material were obtained. An extra needle pass was conducted for DNA collection. The DNA amount, Kirsten rat sarcoma virus (K-ras) mutation type, and mutation allele frequency were compared between the white and red material. Forty patients were enrolled with 68 paired white and red materials. The diagnostic accuracy was slightly higher in the white material (92.5% vs 82.5%, P= .219). On the histology slides, the area of the tumor gland was comparable in both materials, but the total tissue area was larger in the red material (9.74mm2 and 10.74mm2 larger according to generalized linear model and generalized estimating equation, respectively; both, P< .001). The amount of DNA was significantly higher in the red material (2.99 [interquartile range, 1.59-7.29] μg vs .70 [interquartile range, .27-1.24] μg; P< .001). Common pancreatic adenocarcinoma K-ras mutation was identified at a rate of 85% for the white material and 95% for the red material. Regardless of whether red or white material was used, there was a high concordance of K-ras mutation types (34 of 40 [85%]) and a high correlation of mutation allele frequency (ρ= .66, P< .001). In EUS FNB, the red material contains a higher amount of tumor DNA and can be an alternative source for tumor DNA analysis.

The clinical and genomic characteristics of KRAS G12D mutated cancers.

e15151 Background: KRAS mutations are relatively common in solid tumors. It is once considered to be “non-druggable” due to its high affinity to GTP/GDP and lack of other binding sites. Recently, irreversible inhibitors targeting specific KRAS mutations have been developed. We aimed to investigate the correlation of clinical and genomic factors with KRAS G12D mutation in pancreatic cancer (PC), colorectal cancer (CRC) and non-small-cell lung cancer (NSCLC). Methods: We retrospectively reviewed the clinical and genomic data of patients with PC (n = 300), CRC (n = 300), and NSCLC (n = 1800) who provided tumor tissues and matched peripheral blood samples (served as control to eliminate germline variants) for targeted sequencing of 450 cancer-related genes. Experiments were carried out in OrigiMed’s laboratory following the CAP/CLIA standards. Tumor mutation burden (TMB)-high was defined as TMB &gt; 10 muts/Mb. Results: The prevalence of KRAS G12D mutation in PC, CRC and NSCLC was 38.3% (115/300), 15.0% (45/300) and 2.0% (36/1800), respectively. In PC and CRC, G12D was the major type of KRAS mutations, accounting for 44.9% (115/256) and 30.8% (45/146) of all the KRAS mutations, respectively. In contrast, G12C was the most common KRAS mutation in NSCLC (35.9% [79/220]), followed by G12D (16.4% [36/220]). Patients were divided into three groups according to the KRAS mutation status: the G12D (mutated in KRAS G12D), non-G12D (mutated in KRAS, but not G12D), and wild-type (WT; no KRAS mutation) groups. Clinical features including age, sex and disease stage were not associated with the KRAS grouping in PC and CRC. However, the KRAS grouping was significantly correlated with sex in NSCLC (Female vs Male: 1.9% vs 2.1% in G12D, 4.4% vs 13.9% in non-G12D, 93.7% vs 84.1% in WT, P &lt; 0.001). In PC, KRAS G12D and BRAF mutations were mutually exclusive (P &lt; 0.01), while in CRC, KRAS G12D mutation was found to be co-occurring with PIK3CA mutation (P &lt; 0.05). For NSCLC, KRAS G12D mutation was mutually exclusive with EGFR mutation (P &lt; 0.01) and co-occurred with STK11 mutation (P &lt; 0.05). TMB was comparable between the KRAS grouping in PC and CRC. In contrast, TMB was significantly higher in the non-G12D group (median 11.7 [range 0.7-89.8] muts/Mb) compared to the G12D (median 6.9 [range 0-30.9] muts/Mb; P &lt; 0.001) and WT (median 4.6 [range 0-215.2] muts/Mb; P &lt; 0.001) groups in NSCLC. A higher proportion of TMB-high was also observed in the non-G12D group (58.5%) compared to the G12D (22.2%) and WT (22.6%) groups in NSCLC. Conclusions: Patients with KRAS G12D mutation possessed unique clinical and genomic characteristics. It was more prevalent in PC and CRC and was correlated with sex in NSCLC. KRAS G12D mutation co-occurred with STK11 mutation and showed a relatively low TMB value in NSCLC, suggesting that immunotherapy might be ineffective. While KRAS non-G12D mutated NSCLC patients may be favorable to ICI. Our results provide insights into the precision medicine of KRAS G12D-mutated cancers.

The impact of PD-L1 expression and co-mutations on outcome of KRAS-driven non-small-cell lung cancer.

9090 Background: Interest has surged for KRAS mutated ( KRASmut) non-small-cell lung cancer (NSCLC) after approval of the covalent KRASG12C inhibitors sotorasib and adagrasib. It remains unclear, how prognosis of these tumors is influenced by co-mutations and which cases could benefit most from novel drugs alongside immunotherapy (IO) or chemo-immunotherapy (CHT-IO). Methods: This retrospective study included all NSCLC patients with KRASmut NSCLC treated in the Thoraxklinik Heidelberg from 01/2014 until 01/2021. For molecular profiling, PCR-based next-generation sequencing (NGS) was performed with a 40-gene panel, including TP53, KEAP1 and STK11. Date of progression was verified through reevaluation of radiologic images by the investigators according to RECIST v1.1. Stratification was performed according to the type of KRAS mutation (G12C vs. other), presence of TP53, STK11 and KEAP1 co-mutations ( vs. wild-type [WT] status), and the PD-L1 tumor proportion score (TPS &lt; 1 aka PD-L1neg, vs. TPS 1-49, vs. TPS 50+ aka PD-L1high). Results: Among 370 identified patients, no differences (all p-values &gt; 0.08) were observed between KRASG12C (n = 163) and KRASnon-G12C (n = 207) regarding clinicopathological features, like age (median 65 years), sex, smoking status, initial ECOG performance status, PD-L1 TPS, type of treatment in any line, number of treatment lines, and overall survival (OS, 19.4 months in median; details in the poster). In contrast, there was a strong association of PD-L1 TPS with OS (20.2 vs. 9.7 months for PD-L1high vs. PD-L1neg, p = 0.011) and progression-free survival (PFS, 5.7 vs. 1.9 months, p = 0.004) under IO. In addition, specifically within the PD-L1neg subset, OS was longer for KRASG12C compared to KRASother patients (22.6 months vs. 12.1 months, p = 0.032). This was driven by the longer PFS under CHT-IO (9.7 vs. 4.5 months for KRASG12C vs. KRASother, p = 0.005), particularly in the absence of TP53 mutations (8.5 vs. 4.0 months with p = 0.004 for TP53wt patients; p &gt; 0.50 for TP53mut) and KEAP1 mutations (11.3 vs. 5.1 months with p = 0.01 for KEAP1wt patients; p &gt; 0.70 for KEAP1mut). Also, across all patients, KEAP1mut cases showed a trend for shorter PFS under CHT-IO (2.7 vs. 8.0 months, p = 0.07) and IO (1.9 vs. 3.9 months, p = 0.081), as well as shorter OS (15.9 vs. 19.5 months, p = 0.068) compared to KEAP1wt, in contrast to STK11mut cases (p = 0.42-0.92 for the same comparisons). Overall, KRASmut NSCLC after chemotherapy and immunotherapy showed poor prognosis under standard therapies with a median PFS of 3 months, and a median OS of 6.8 months. Conclusions: In PD-L1neg NSCLC, KRASG12C is associated with better outcome under CHT-IO and longer OS compared to KRASother, especially in the absence of TP53 and KEAP1 co-mutations. KEAP1, but not STK11 mutations are associated with impaired benefit from (CHT-)IO in KRASmut NSCLC. Treatment of KRASmut NSCLC after chemo-immunotherapy represents an unmet medical need.

Comprehensive genomic landscape in pancreatic cancer using whole-exome sequencing.

e16307 Background: Pancreatic ductal adenocarcinoma is one of the fatal malignancies in the world, mostly as a result of the absence of early detection and specific treatment solutions. Consequently, identifying mutational profiles and molecular biomarker are essential for increasing the viability of precision therapy for pancreatic cancer. Methods: We gathered blood and tumour tissue samples from 47 Chinese pancreatic cancer patients and used whole-exome sequencing (WES) to evaluate the genetic landscape. Results: Our results showed the most frequently somatic alteration genes were KRAS (74.5%), TP53 (51.1%), SMAD4 (17%), ARID1A (12.8%), CDKN2A (12.8%), TENM4 (10.6%), TTN (8.5%), RNF43 (8.5%), FLG (8.5%) and GAS6 (6.4%) in Chinese pancreatic ductal adenocarcinoma patients. We also found that three deleterious germline mutations ( ATM c.4852C &gt; T/p. R1618*, WRN c.1105C &gt; T/p. R369*, PALB2 c.2760dupA/p. Q921Tfs*7) and two novel fusions ( BRCA1-RPRML, MIR943 (intergenic)- FGFR3). When compared to the Cancer Genome Atlas (TCGA) database, there is a greater mutation frequency of TENM4 (10.6% vs. 1.6%, p= 0.01), GAS6 (6.4% vs. 0.5%, p= 0.035), MMP17 (6.4% vs. 0.5%, p= 0.035), ITM2B (6.4% vs. 0.5%, p= 0.035) and USP7 (6.4% vs. 0.5%, p= 0.035) as well as a reduced mutation frequency of SMAD4 (17.0% vs. 31.5%, p= 0.075) and CDKN2A (12.8% vs. 47.3%, p&lt; 0.001) were observed in the Chinese cohort. Among the 41 individual examined for PD-L1 expression, 15 (36.6%) had positive PD-L1 expression. The median tumour mutational burden (TMB) was found to be 12 muts (range, 0-124). The TMB index was higher in patients with mutant-type KRAS MUT/ TP53 MUT ( p&lt; 0.001), CDKN2A ( p= 0.547), or SMAD4 ( p= 0.064) compared to patients with wild-type KRAS/ TP53, CDKN2A, or SMAD4. Conclusions: We exhibited real-world genetic traits and new alterations in Chinese individuals with cancer of pancreas, which might have interesting implications for future individualized therapy and medication development.

Clinical and genetic characteristics in pancreatic cancer from Chinese patients revealed by whole exome sequencing.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most fatal malignancies worldwide, mostly as a result of the absence of early detection and specific treatment solutions. Consequently, identifying mutational profiles and molecular biomarkers is essential for increasing the viability of precision therapy for pancreatic cancer. We collected blood and tumor tissue samples from 47 Chinese pancreatic cancer patients and used whole-exome sequencing (WES) to evaluate the genetic landscape. Our results showed the most frequently somatic alteration genes were KRAS (74.5%), TP53(51.1%), SMAD4 (17%), ARID1A (12.8%), CDKN2A (12.8%), TENM4 (10.6%), TTN (8.5%), RNF43(8.5%), FLG (8.5%) and GAS6 (6.4%) in Chinese PDAC patients. We also found that three deleterious germline mutations (ATM c.4852C>T/p. R1618*, WRN c.1105C>T/p. R369*, PALB2 c.2760dupA/p. Q921Tfs*7) and two novel fusions (BRCA1-RPRML, MIR943 (intergenic)-FGFR3). When compared to the Cancer Genome Atlas (TCGA) database, there is a greater mutation frequency of TENM4 (10.6% vs. 1.6%, p = 0.01), GAS6(6.4% vs. 0.5%, p = 0.035), MMP17(6.4% vs. 0.5%, p = 0.035), ITM2B (6.4% vs. 0.5%, p = 0.035) and USP7 (6.4% vs. 0.5%, p= 0.035) as well as a reduced mutation frequency of SMAD4 (17.0% vs. 31.5%, p = 0.075) and CDKN2A (12.8% vs. 47.3%, p < 0.001) were observed in the Chinese cohort. Among the 41 individuals examined for programmed cell death ligand 1(PD-L1) expression, 15 (36.6%) had positive PD-L1 expression. The median tumor mutational burden (TMB) was found to be 12muts (range, 0124). The TMB index was higher in patients with mutant-type KRAS MUT/TP53 MUT (p < 0.001), CDKN2A (p = 0.547), or SMAD4 (p = 0.064) compared to patients with wild-type KRAS/TP53, CDKN2A, or SMAD4. We exhibited real-world genetic traits and new alterations in Chinese individuals with cancer of the pancreas, which might have interesting implications for future individualized therapy and medication development.

Genomic and transcriptomic insights into the precision treatment of pulmonary enteric adenocarcinoma

BackgroundPulmonary enteric adenocarcinoma (PEAC) is a rare subtype of lung adenocarcinoma. More investigations about precision therapy in PEAC were required to improve the prognosis. Methods: Twenty-four patients with PEAC were enrolled in this study. Tumor tissue samples were available from 17 patients for both DNA and RNA based next-generation sequencing, PD-L1 IHC staining and PCR-based microsatellite instability (MSI) analysis. Results: TP53 (70.6%) and KRAS (47.1%) were the most frequently mutated genes in PEAC. For KRAS mutations, the prevalence of G12D (37.5%) and G12V (37.5%) was higher than G12A (12.5%) and G12C (12.5%). Actionable mutations in receptor tyrosine kinase (including one EGFR and two ALK mutations), PI3K/mTOR, RAS/RAF/MEK, homologous recombination repair (HRR) and cell cycle signaling pathways were identified in 94.1% of patients with PEAC. While PD-L1 expression was observed in 17.6% (3/17) patients, no MSI-H patients were identified. Transcriptomic data showed that two patients with positive PD-L1 expression had relatively high immune infiltration. In addition, prolonged survival was obtained with the treatment of osimertinib, ensartinib, and immunotherapy combined with chemotherapy in two EGFR-mutated, one ALK-rearranged, and one PD-L1 expressed patients, respectively. Conclusion: PEAC is a disease of genetic heterogeneity. The administration of EGFR and ALK inhibitors was effective in patients with PEAC. PD-L1 expression and KRAS mutation type may be used as predictive biomarkers for immunotherapy in PEAC. This study provided both theoretical basis and clinical evidence for PEAC.

Impact of KRAS mutation variants on clinicopathological features and outcomes in patients with metastatic pancreatic adenocarcinoma.

749 Background: Most pancreatic ductal adenocarcinoma (PDAC) exhibit KRAS mutations. A subset of PDACs harbor KRAS wild-type (WT) and appear to carry better prognosis. Given the recent development of KRAS G12C inhibitors, it is imperative to better understand KRAS variants in contemporary cohorts. Herein, we characterized the prevalence of the different KRAS variants and its impact on clinicopathological features and outcomes. Methods: A retrospective review of patients with metastatic PDAC and a known KRAS mutation status who underwent next-generation sequencing (NGS) from liver biopsy was performed. Descriptive statistics analyzed the differences in clinicodemographic features by presence and type or absence of KRAS variants. Kaplan-Meier method was used to assess overall survival (OS). Cox regression was used to study the relationship between KRAS variants and OS when confounding factors were adjusted. Results: 50 pts with PDAC diagnosed at a single community-based institution between 2011-2018 were evaluated. Median age at diagnosis was 68 years (24-80 range), 68% were male, and 76% presented with metastases. Most (86%) tumors harbored KRAS mutations. The most frequent variants were G12V (44%), G12D (37%), G12R (9%), Q61R (5%), G12C (2%), Q61H (2%). Sex (p=0.03) and tumor differentiation (p=0.04) varied according to mutation status and KRAS variant subtype. However, no significant difference was observed in age, race, smoking status, location of primary, and performance status (PS) in KRAS variants. Overall, median OS in months was 8.9 (95% CI 6.7-14.3) for KRAS mutated patients and 11.2 (95% CI 2.1-33.5) for patients with WT. Among patients with KRAS mutations, median OS in months by variant was as following: G12V 9.6 (95%CI 6.6-17.2), G12D 8.4 (95%CI 3.9-15.4), G12R 8.2 (95%CI 1-20.8), and Q61R 11.8 (95%CI 1.3-22.3). However, these differences did not reach statistical significance (p=0.72). In multivariable analyses, female sex (HR 0.16, 95% CI 0.03-0.81, p=0.03) and no receipt of chemotherapy (38.5 95% CI 2.1-698.50, p=0.01) were significant predictors of death. KRAS mutation variant type was not an independent predictor of death. Conclusions: No significant difference was observed in metastatic PDAC with KRAS mutations compared to WT. However, numerical difference in OS were observed among the various KRAS mutation type. Hence, larger studies are needed to better define the effect of KRAS type on outcomes.

Tailored modulation of stemness and drug resistance marker characteristics in K-Ras mutant lung cancer cells via PD-L1 gene suppression

AimsWe aimed to analyze the association of tumor cell-specific Programmed Cell Death Ligand 1 (PD-L1) expression with stemness markers and multi-drug resistance genes in non-small cell lung cancer. Main methodsATP Binding Cassette Subfamily G Member 2 (ABCG2), Aldehyde dehydrogenase 1 family, member A1 (ALDH1A1), CD44, Epithelial cell adhesion molecule (EPCAM), Kruppel-like factor 4 (KLF4), MYC Proto-Oncogene (MYC), Nanog Homeobox (NANOG), SRY-Box Transcription Factor 2 (SOX2) as well as ATP Binding Cassette Subfamily C Member (ABCC) 1–6, ABCC10–12 with ATP Binding Cassette Subfamily B Member (ABCB) 1 and ABCB4–9 belongs to ABC transporters family were analyzed and their correlation with PD-L1 was evaluated using Cancer Cell Line Encyclopedia and The Cancer Genome Atlas data sets. We validated potential lung cancer stemness markers harboring ABCG2, CD44, ALDH1A1 and SOX-2, which are affected as a result of siRNA-mediated suppression of PD-L1 via flow cytometry. K-Ras downstream signaling proteins as well as multidrug resistance proteins were also investigated. Key findingsPD-L1 was found to be positively correlated with CD44, whereas negatively correlated with ALDH1A1 (Pearson r = 0.44, r = −0.48; respectively) in 45 K-Ras mutated NSCLC cells based on CCLE database. While ABCC5 was dominantly decreased in K-Ras mutant lung cancer cells affected by PD-L1 gene suppression, expression changes were observed in the activation of distinct signaling pathways in a cell line-dependent manner. SignificanceThe evaluation of markers in lung adenocarcinoma with different types of K-Ras mutations in terms of both stemness and drug resistance markers will contribute to the development of personalized immunotherapy regimens.

KRAS mutated Non-Small Lung Carcinoma: A Real World Context from the Indian subcontinent.

KRAS, although a common variant of occurrence (~20% of non-small-cell lung carcinoma [NSCLC]) has been untargetable, owing to the molecular structure which inherently prevents drug binding. KRAS mutations in NSCLC are associated with distinct clinical profiles including smokers and mucinous histology. KRAS G12C mutations account for ~40% KRAS altered NSCLC, but NSCLC being a geographically diverse disease, the features may be distinct in this part of the world. This is a single-center experience of KRAS-mutated NSCLC including clinical, imaging, pathologic features, and treatment patterns and outcomes. This is a single-center retrospective study of KRAS-mutated NSCLC. The clinicopathological features and outcomes were retrieved and collated from the medical record archives of the hospital. Fifty (30.6%) patients with advanced-stage NSCLC with alterations in the KRAS gene were enrolled in the 163 patients who were tested for KRAS alterations. The median age was 61 years. Molecular detection revealed three main types of KRAS mutations viz-a-vis: G12C in 17 (34%), G12V in 9 (18%), and G12D in 6 (12%) patients. Comparing G12C versus the non-G12C mutated cases, co-mutations were common in the non-G12C subgroup (p < 0.05). Among the 36, who were treated at our center, all received chemotherapy as the first line with a median progression-free survival (PFS)of 5.4months. The PFS of G12C was higher than the non-G12C subgroup (6.4 vs 3.8months). This is the largest single-center experience from the Indian subcontinent for KRAS-mutated NSCLC with distinct clinical features. It highlights the unmet need for G12C inhibitors in our country, where prevalence is equivalent to the West.

Identification of Synergistic Drug Combinations to Target KRAS-Driven Chemoradioresistant Cancers Utilizing Tumoroid Models of Colorectal Adenocarcinoma and Recurrent Glioblastoma.

Treatment resistance is observed in all advanced cancers. Colorectal cancer (CRC) presenting as colorectal adenocarcinoma (COAD) is the second leading cause of cancer deaths worldwide. Multimodality treatment includes surgery, chemotherapy, and targeted therapies with selective utilization of immunotherapy and radiation therapy. Despite the early success of anti-epidermal growth factor receptor (anti-EGFR) therapy, treatment resistance is common and often driven by mutations in APC, KRAS, RAF, and PI3K/mTOR and positive feedback between activated KRAS and WNT effectors. Challenges in the direct targeting of WNT regulators and KRAS have caused alternative actionable targets to gain recent attention. Utilizing an unbiased drug screen, we identified combinatorial targeting of DDR1/BCR-ABL signaling axis with small-molecule inhibitors of EGFR-ERBB2 to be potentially cytotoxic against multicellular spheroids obtained from WNT-activated and KRAS-mutant COAD lines (HCT116, DLD1, and SW480) independent of their KRAS mutation type. Based on the data-driven approach using available patient datasets (The Cancer Genome Atlas (TCGA)), we constructed transcriptomic correlations between gene DDR1, with an expression of genes for EGFR, ERBB2-4, mitogen-activated protein kinase (MAPK) pathway intermediates, BCR, and ABL and genes for cancer stem cell reactivation, cell polarity, and adhesion; we identified a positive association of DDR1 with EGFR, ERBB2, BRAF, SOX9, and VANGL2 in Pan-Cancer. The evaluation of the pathway network using the STRING database and Pathway Commons database revealed DDR1 protein to relay its signaling via adaptor proteins (SHC1, GRB2, and SOS1) and BCR axis to contribute to the KRAS-PI3K-AKT signaling cascade, which was confirmed by Western blotting. We further confirmed the cytotoxic potential of our lead combination involving EGFR/ERBB2 inhibitor (lapatinib) with DDR1/BCR-ABL inhibitor (nilotinib) in radioresistant spheroids of HCT116 (COAD) and, in an additional devastating primary cancer model, glioblastoma (GBM). GBMs overexpress DDR1 and share some common genomic features with COAD like EGFR amplification and WNT activation. Moreover, genetic alterations in genes like NF1 make GBMs have an intrinsically high KRAS activity. We show the combination of nilotinib plus lapatinib to exhibit more potent cytotoxic efficacy than either of the drugs administered alone in tumoroids of patient-derived recurrent GBMs. Collectively, our findings suggest that combinatorial targeting of DDR1/BCR-ABL with EGFR-ERBB2 signaling may offer a therapeutic strategy against stem-like KRAS-driven chemoradioresistant tumors of COAD and GBM, widening the window for its applications in mainstream cancer therapeutics.

The Effect of the Kirsten Rat Sarcoma Viral Oncogene Homolog (Kras) Proto-Oncogene, GTPase Genetic Polymorphism on the Safety and Efficacy of Bevacizumab Combination Treatment Regimens for Patients with Nonsquamous, Non-Small Cell Lung Cancer with Brain Metastases.

Background:Non-small cell lung cancer with brain metastasis (NSCLCBM) is normally observed in advanced-stage patients. Bevacizumab has shown to improve survival in the first-line treatment of metastatic brain NSCLC when added as a bolus plus irinotecan. However, a better understanding of the molecular mechanism is required to further drive progress in this field.Methods:A total of 155 patients were selected, including 42.10% with Kirsten rat sarcoma viral oncogene homolog (Kras)-mutant tumors. Of the 155 patients, 62.04% had developed brain metastasis (BM). Seven functional single-nucleotide polymorphisms (SNPs) in the Kras gene were extracted from the HapMap SNP database and were used for genotyping. The haplologit command in Statistical Software for Data Science (STATA) was used to model the association between haplotypes and case status. A Cox analysis was used to evaluate the prognostic value of the SNPs.Results:Among the patients treated with combination regimens, recurrence after local treatment was more frequent in those with two types of Kras mutations (odds ratio [OR] = 2.033 [0.5015–4.2552], p = 0.009). Among the patients with untreated BM, overall survival was shorter than that of patients with Kras mutations according to univariate analysis (OR = 5.130 [1.240–41.012], p = 0.033).Conclusions:Kras mutations have a predictive role for BM recurrence and outcome in patients with NSCLC treated with bevacizumab combination regimens.