KRAS G12C mutation as a poor prognostic marker of pemetrexed treatment in non-small cell lung cancer

MYC and KRAS cooperation: from historical challenges to therapeutic opportunities in cancer

RAS and MYC rank amongst the most commonly altered oncogenes in cancer, with RAS being the most frequently mutated and MYC the most amplified. The cooperative interplay between RAS and MYC constitutes a complex and multifaceted phenomenon, profoundly influencing tumor development. Together and individually, these two oncogenes regulate most, if not all, hallmarks of cancer, including cell death escape, replicative immortality, tumor-associated angiogenesis, cell invasion and metastasis, metabolic adaptation, and immune evasion. Due to their frequent alteration and role in tumorigenesis, MYC and RAS emerge as highly appealing targets in cancer therapy. However, due to their complex nature, both oncogenes have been long considered "undruggable" and, until recently, no drugs directly targeting them had reached the clinic. This review aims to shed light on their complex partnership, with special attention to their active collaboration in fostering an immunosuppressive milieu and driving immunotherapeutic resistance in cancer. Within this review, we also present an update on the different inhibitors targeting RAS and MYC currently undergoing clinical trials, along with their clinical outcomes and the different combination strategies being explored to overcome drug resistance. This recent clinical development suggests a paradigm shift in the long-standing belief of RAS and MYC "undruggability", hinting at a new era in their therapeutic targeting.

KRAS as a Prognostic and Predictive Marker in Metastatic Non-Small Cell Lung Carcinoma: A Systematic Review

Metastatic non-small cell lung cancer (NSCLC) poses a significant clinical challenge, prompting a focused investigation into the role of KRAS mutations in prognosis and treatment response. Targeted therapies offer promising avenues for intervention, motivating a comprehensive analysis of existing evidence. Conducted in June 2023, our review delved into MEDLINE (Medical Literature Analysis and Retrieval System Online), Embase, Scopus, and the Cochrane Register of Controlled Trials. Rigorous inclusion and exclusion criteria guided the selection of 12 articles, comprising two randomized controlled trials (RCTs) and 10 observational studies. Multiple investigators independently executed data extraction, evaluating prognostic factors (overall and progression-free survival) and predictive outcomes (treatment and objective response). The Newcastle-Ottawa Scale (NOS) and modified Jadad scores were used for study quality assessment of observational studies and RCTs, respectively. From an initial pool of 120 articles, the 12 selected studies, spanning 2013 to 2022, encompassed 2,845 metastatic NSCLC patients. KRAS mutations, particularly the G12C variant, emerged as a pivotal factor influencing treatment response. Notably, KRAS wild type patients displayed enhanced responses to platinum-based chemotherapy, while those with KRAS mutations exhibited favourable outcomes with immune checkpoint inhibitors (ICIs). The role of KRAS mutations as prognostic indicators in metastatic NSCLC is underscored by this systematic review, with implications for both survival and treatment response. The discernment between KRAS wild type and mutant patients offers insights into tailored therapeutic strategies, with platinum-based chemotherapy and immune checkpoint inhibitors emerging as context-dependent options. Nevertheless, more research is required to solidify the predictive role of KRAS and explore the efficacy of KRAS inhibitors and other targeted therapies, paving the way for refined and personalized interventions in the management of metastatic NSCLC.

LncRNA-NEAT1 facilitates autophagy to boost pemetrexed resistance in lung adenocarcinoma via the mir-379-3p/HIF1A pathway

BACKGROUND

As a primary chemotherapeutic agent for lung adenocarcinoma (LUAD), pemetrexed (PEM) faces the challenge of resistance development in cancer cells due to its chronic use, which compromises its therapeutic benefits. LncRNA-NEAT1, implicated in the promotion of cancer, is a key player in LUAD. The objective of this study is to explore the contribution of lncRNA-NEAT1 to PEM resistance in LUAD and to dissect the molecular mechanisms involved.

METHOD

The expression levels of lncRNA-NEAT1 in LUAD tissues and cells were deciphered using the TCGA database and qRT-PCR. To delve into the functional implications of lncRNA-NEAT1, we engineered plasmids to modulate its expression levels in PEM-resistant A549 cells. PEM resistance in the modified cells was then quantitatively assessed via a panel of assays including cell counting kit-8 (CCK-8), and colony formation, and flow cytometry. To predict the interaction sites between lncRNA-NEAT1 and miR-379-3p, along with the miR-379-3p and hypoxia-inducible factor (HIF1A), we referred to the StarBase and TargetScan databases. The interplay between these RNA molecules was further characterized by RNA immunoprecipitation (RIP) and dual-luciferase reporter assays, while the expression of autophagy-related proteins LC3I, LC3II, and Beclin1 was profiled using western blot (WB).

RESULTS

Abundant lncRNA-NEAT1 expression was observed in LUAD tissues and cell lines. Its depletion resulted in impeded growth of A549/PEM cells, enhanced apoptotic rates, and a lowered threshold for PEM to exert a half-maximal inhibitory effect. The interplay between lncRNA-NEAT1 and miR-379-3p, as evidenced by dual-luciferase reporter assays, RIP, and qRT-PCR, led to the upregulation of HIF1A. WB and CCK-8 outcomes illustrated that the autophagy and PEM resistance were compromised when HIF1A expression was curtailed by miR-379-3p mimics in A549/PEM cells. The restoration of these effects was observed upon lncRNA-NEAT1-mediated downregulation of miR-379-3p.

CONCLUSION

Our study illuminates the role of lncRNA-NEAT1 in LUAD, where it mediates resistance to PEM through the activation of autophagy via the miR-379-3p/HIF1A axis. This work paves the way for new therapeutic strategies for managing PEM resistance in LUAD patients.

A Critical Review of the Prognostic and Predictive Implications of KRAS and STK11 Mutations and Co-Mutations in Metastatic Non-Small Lung Cancer

The Kirsten rat sarcoma viral oncogene homolog (KRAS) and serine/threonine kinase 11 (STK11) co-mutations are associated with the diverse phenotypic and heterogeneous oncogenic subtypes in non-small cell lung cancer (NSCLC). Due to extensive mixed evidence, there needs to be a review of the recent KRAS and STK11 mutation literature to better understand the potential clinical applications of these genomic biomarkers in the current treatment landscape. This critical review highlights the clinical studies that have elucidated the potential prognostic and predictive implications of KRAS mutations, STK11 mutations, or KRAS/STK11 co-mutations when treating metastatic NSCLC across various types of treatments (e.g., immune checkpoint inhibitors [ICIs]). Overall, KRAS mutations are associated with poor prognoses and have been determined to be a valid but weak prognostic biomarker among patients diagnosed with NSCLC. KRAS mutations in NSCLC have shown mixed results as a predictive clinical biomarker for immune checkpoint inhibitor treatment. Overall, the studies in this review demonstrate that STK11 mutations are prognostic and show mixed results as predictive biomarkers for ICI therapy. However, KRAS/STK11 co-mutations may predict primary resistance to ICI. Prospective KRAS/STK11-biomarker-driven randomized trials are needed to assess the predictive effect of various treatments on the outcomes for patients with metastatic NSCLC, as the majority of the published KRAS analyses are retrospective and hypothesis-generating in nature.

Oncogenic lncRNA MALAT-1 recruits E2F1 to upregulate RAD51 expression and thus promotes cell autophagy and tumor growth in non-small cell lung cancer

INTRODUCTION

LncRNA MALAT-1 expression is involved in regulating activities of non-small-cell lung cancer (NSCLC) cells. This study aimed to investigate the effects of lncRNA MALAT-1 on chemosensitivity of NSCLC cells by regulating autophagy.

METHODS

We first validated the expression of lncRNA MALAT-1 in NSCLC cell lines. NSCLC cell lines with high lncRNA MALAT-1 expression were exposed to doxorubicin (DOX) to assess chemosensitivity. Further LncMAP database retrieval and ChIP, RIP and luciferase activity assays were conducted to explore interplay between lncRNA MALAT-1, RAD51, and E2F1. Immunofluorescence staining was performed to evaluate formation of autophagosomes in NSCLC cells. Ectopic expression and knockdown methods were used for in vitro mechanism experiments and in vivo substantiation.

RESULTS

LncRNA MALAT-1 was overexpressed in NSCLC cells, and could promote NSCLC cell autophagy and inhibit its chemosensitivity. In vitro cell mechanism verification experiments showed that lncRNA MALAT-1 could recruit transcription factor E2F1 to bind to the promoter of RAD51, so as to promote the transcriptional expression of RAD51. In addition, cell function experiments in vitro showed that ectopically expressed lncRNA MALAT-1 promoted NSCLC cell autophagy and inhibited its chemosensitivity, while RAD51 knockdown negated its effect. Finally, in vivo animal experiments confirmed that lncRNA MALAT-1 silencing could impede the tumor growth.

CONCLUSIONS

Taken together, this study revealed that silencing lncRNA MALAT-1 enhanced chemosensitivity of NSCLC cells by promoting autophagy, highlighting a feasible approach to prevent chemoresistance in NSCLC treatment.

Definitive Chemoradiation and Durvalumab Consolidation for Locally Advanced, Unresectable KRAS-mutated Non-Small Cell Lung Cancer

BACKGROUND

Consolidation durvalumab immunotherapy following definitive chemoradiation (CRT) for unresectable stage III non-small cell lung cancer (NSCLC) improves overall survival. As therapeutic options for patients with KRAS-driven disease evolve, more understanding regarding genomic determinants of response and patterns of progression for durvalumab consolidation is needed to optimize outcomes.

METHODS

We conducted a single-institutional retrospective analysis of real-world patients with locally advanced, unresectable NSCLC who completed CRT and received durvalumab consolidation. Kaplan-Meier analyses compared progression-free survival (PFS) and overall survival (OS) from start of durvalumab consolidation between patients with KRAS-mutated and non-mutated tumors. Fisher's exact test was used to compare rates of intrathoracic or extrathoracic progression.

RESULTS

Of 74 response-evaluable patients, 39 had clinical genomic profiling performed. 18 patients had tumors with KRAS mutations, 7 patients had tumors with non-KRAS actionable alterations (EGFR, ALK, ERBB2, BRAF, MET, RET, or ROS1), and 14 patients had tumors without actionable alterations. Median PFS for the overall cohort was 16.1 months. PFS for patients with KRAS-mutated NSCLC was 12.6 months versus 12.7 months for patients with non-actionable tumors (P= 0.77, log-rank). Fisher's exact test revealed a statistically significantly higher rate of extrathoracic progression versus intrathoracic-only progression for patients with KRAS-driven disease compared to patients with non-actionable tumors (P= 0.015).

CONCLUSION

Patients with KRAS-mutated NSCLC derived similar benefit from durvalumab as patients with non-actionable tumors. A higher rate of extrathoracic progression was also observed among the patients with KRAS-mutated NSCLC compared to patients with non-actionable tumors. This highlights the potential unmet needs for novel systemic therapies and surveillance methods for KRAS-mutated stage III NSCLC.

Therapeutic Outcomes and Clinical Features of Advanced Non-Small Cell Lung Cancer Carrying KRAS Mutations: A Multicenter Real-life Retrospective Study

INTRODUCTION

Targeting Kirsten Rat Sarcoma (KRAS) has been deemed impossible for long time, but new drugs have recently demonstrated promising results. Evidence on the outcome of KRAS-mutant advanced-NSCLC treated with new standard regimens are still scarce. Thus, we aimed at assessing the incidence and clinical impact of KRAS mutations in a real-life population of advanced-NSCLC, exploring the prognostic significance of distinct alterations.

MATERIALS AND METHODS

The present multicenter retrospective study, conducted by 5 Italian Centers from January 2018 to February 2020, involved 297 advanced KRAS mutant NSCLC. Complete clinico-pathological data were evaluated.

RESULTS

Out of 297 patients, 130 carried KRAS_G12C mutation, while 167 presented with mutations other than G12C. Within KRAS_non-G12C group, 73%, 16.8% and 8.9% harboured G12X, codon 13 and Q61H alterations, respectively. No significant differences in survival outcome and treatment response were documented according to KRAS_G12C versus non-G12C, nor KRAS_G12C versus G12X versus other mutations. On univariate analysis ECOG PS, number and sites of metastatic lesions and PD-L1 status significantly impacted on survival. A clear trend towards worse prognosis was apparent in chemotherapy-treated patients, while immunotherapy-based regimens were associated to prolonged survival. Investigating the outcome of PD-L1 ≥ 50% population, we did not detect any significant difference between KRAS_G12C and non-G12C subsets.

CONCLUSION

Here, we report on real-life data from a large retrospective cohort of advanced NSCLC harbouring KRAS alterations, with particular attention to G12C mutation. Our study offers useful clues on survival outcome, therapeutic response and clinico-pathological correlations in KRAS-mutant setting, especially in the upcoming era of KRAS G12C targeting therapy.

Light at the end of the tunnel: Clinical features and therapeutic prospects of KRAS mutant subtypes in non-small-cell lung cancer

Lung cancer is one of the most common causes of cancer-related deaths, and non-small-cell lung cancer (NSCLC) accounts for approximately 85% of all lung cancer cases. Kirsten rat sarcoma virus (KRAS), one of the three subtypes of the RAS family, is the most common oncogene involved in human cancers and encodes the key signaling proteins in tumors. Oncogenic KRAS mutations are considered the initiating factors in 30% of NSCLC cases, accounting for the largest proportion of NSCLC cases associated with driver mutations. Because effective inhibition of the related functions of KRAS with traditional small-molecule inhibitors is difficult, the KRAS protein is called an "undruggable target." However, in recent years, the discovery of a common mutation in the KRAS gene, glycine 12 mutated to cysteine (G12C), has led to the design and synthesis of covalent inhibitors that offer novel strategies for effective targeting of KRAS. In this review, we have summarized the structure, function, and signal transduction pathways of KRAS and discussed the available treatment strategies and potential treatment prospects of KRAS mutation subtypes (especially G12C, G12V, and G12D) in NSCLC, thus providing a reference for selecting KRAS mutation subtypes for the treatment of NSCLC.

Molecular Biology and Therapeutic Perspectives for K-Ras Mutant Non-Small Cell Lung Cancers

In non-small cell lung cancer (NSCLC) the most common alterations are identified in the Kirsten rat sarcoma viral oncogene homolog (KRAS) gene, accounting for approximately 30% of cases in Caucasian patients. The majority of mutations are located in exon 2, with the c.34G > T (p.G12C) change being the most prevalent. The clinical relevance of KRAS mutations in NSCLC was not recognized until a few years ago. What is now emerging is a dual key role played by KRAS mutations in the management of NSCLC patients. First, recent data report that KRAS-mutant lung AC patients generally have poorer overall survival (OS). Second, a KRAS inhibitor specifically targeting the c.34G > T (p.G12C) variant, Sotorasib, has been approved by the U.S. Food and Drug Administration (FDA) and by the European Medicines Agency. Another KRAS inhibitor targeting c.34G > T (p.G12C), Adagrasib, is currently being reviewed by the FDA for accelerated approval. From the description of the biology of KRAS-mutant NSCLC, the present review will focus on the clinical aspects of KRAS mutations in NSCLC, in particular on the emerging efficacy data of Sotorasib and other KRAS inhibitors, including mechanisms of resistance. Finally, the interaction between KRAS mutations and immune checkpoint inhibitors will be discussed.

Retrospective Comparative Analysis of KRAS G12C vs. Other KRAS Mutations in mCRC Patients Treated With First-Line Chemotherapy Doublet + Bevacizumab

Background

KRAS mutations in metastatic colorectal cancer (mCRC) define a subset of tumors that have primary resistance to anti-EGFR-based therapy. Data concerning whether different KRAS mutations may also have a prognostic value are lacking. Furthermore, novel KRAS G12C inhibitors are currently in development. The aim of our analysis was to compare response rates in patients treated with first-line chemotherapy doublet + Bevacizumab among different KRAS variants. Secondary end-points were progression free survival (PFS) and overall survival (OS).

Methods

Patients with KRAS mutated mCRC treated with either FOLFIRI/FOLFOX/XELOX + Bevacizumab were eligible for enrollment. Patients whose tumor harbored NRAS mutations or that coexpressed also BRAF mutations were excluded from this retrospective analysis. Patients’ individual data were collected from patients’ records. Propensity score matching (nearest method, 1:2 ratio) was used to define the two different groups of patients for comparison (KRAS G12C mutated vs other KRAS variants). Eastern Cooperative Oncology Group Performance Status (ECOG PS), sex, metastatic site of involvement, synchronous vs metachronous metastatic disease, tumor sidedness, mucinous histology, primary tumor surgery, more than two lines of treatment for metastatic disease, and radical surgery of metastases were used as matching factors. Response rate (RR) was calculated by RECIST 1.1 criteria. Both progression free-survival and overall survival were calculated by Kaplan–Meier method. Categorical variables were compared by Fisher exact test for binomial variables and by chi-square test for all other instances. The level of statistical significance p was set at 0.05 for all tests.

Results

A total of 120 patients were assessed in the final analysis. Out of the 120 patients, 15 (12%) were KRAS G12C mutated. In the whole cohort of patients, 59/120 (49%) had partial response (PR), 42/120 (35%) had stable disease (SD), and 19/120 (16%) had progressive disease (PD) as the best response. In KRAS G12C patients, 4/15 (27%) had PR, 6/15 (40%) had SD, and the remaining 5/15 (33%) had PD as the best response. In patients with other KRAS mutations, 55/105 (52%) had PR, 37/105 (35%) had SD, and the remaining 13/105 (12%) had PD as the best response. The difference in RR between the two groups of patients was statistically significant (p=0.017). On the other hand, no difference in PFS (p=0.76) and OS (p=0.56) was observed. After matching procedures, the difference in response rates between KRAS G12C mutated patients vs the matched cohort of patients with other KRAS mutations remained statistically significant (p=0.016). KRAS G12C mutations were not associated with differences in sites of metastatic involvement, sex, and ECOG PS. On the other hand, synchronous vs metachronous metastatic disease (p=0.039), age > 75 years (p=0.043), and mucinous histology (p=0.008) were more frequent in G12C mutated tumors.

Conclusions

In our cohort of patients, it was observed that KRAS G12C mutations are associated with worse response rates compared to other KRAS variants when treated with standard chemotherapy doublet + Bevacizumab. On the other hand, both PFS and OS were not significantly different. Based on these findings, we believe that new treatment options focused on KRAS G12C inhibition should be tested mainly in first-line setting and in addition to standard chemotherapy doublet + Bevacizumab for mCRC patients, as they might “fill the gap” in response rates that was seen in our study.

KRAS G12C-mutated advanced non-small cell lung cancer: A real-world cohort from the German prospective, observational, nation-wide CRISP Registry (AIO-TRK-0315)

OBJECTIVES

After decades of unsuccessful efforts in inhibiting KRAS, promising clinical data targeting the mutation subtype G12C emerge. Since little is known about outcome with standard treatment of patients with G12C mutated non-small cell lung cancer (NSCLC), we analyzed a large, representative, real-world cohort from Germany.

PATIENTS AND METHODS

A total of 1039 patients with advanced KRAS-mutant or -wildtype NSCLC without druggable alterations have been recruited in the prospective, observational registry CRISP from 12/2015 to 06/2019 by 98 centers in Germany. Details on treatment, best response, and outcome were analyzed for patients with KRAS wildtype, G12C, and non-G12C mutations.

RESULTS

Within the study population, 160 (15.4 %) patients presented with KRAS G12C, 251 (24.2 %) with non-G12C mutations, 628 (60.4 %) with KRAS wildtype. High PD-L1 expression (Tumor Proportion Score, TPS > 50 %) was documented for 28.0 %, 43.5 %, and 28.9 % (wildtype, G12C, non-G12C) of the tested patients; 68.8 %, 89.3 %, and 87.7 % of the patients received first-line treatment combined with an immune checkpoint-inhibitor in 2019. TPS > 50 % vs. TPS < 1 % was associated with a significantly decreased risk of mortality in a multivariate Cox model (HR 0.39, 95 % CI 0.26-0.60, p=<0.001). There were no differences in clinical outcome between KRAS wildtype, G12C or non-G12C mutations and KRAS mutational status was not prognostic in the model.

CONCLUSION

Here we describe the so far largest prospectively recruited cohort of patients with advanced NSCLC and KRAS mutations, with special focus on the G12C mutation. These data constitute an extremely valuable historical control for upcoming clinical studies that employ KRAS inhibitors.

Notch Transduction in Non-Small Cell Lung Cancer

The evolutionarily-conserved Notch signaling pathway plays critical roles in cell communication, function and homeostasis equilibrium. The pathway serves as a cell-to-cell juxtaposed molecular transducer and is crucial in a number of cell processes including cell fate specification, asymmetric cell division and lateral inhibition. Notch also plays critical roles in organismal development, homeostasis, and regeneration, including somitogenesis, left-right asymmetry, neurogenesis, tissue repair, self-renewal and stemness, and its dysregulation has causative roles in a number of congenital and acquired pathologies, including cancer. In the lung, Notch activity is necessary for cell fate specification and expansion, and its aberrant activity is markedly linked to various defects in club cell formation, alveologenesis, and non-small cell lung cancer (NSCLC) development. In this review, we focus on the role this intercellular signaling device plays during lung development and on its functional relevance in proximo-distal cell fate specification, branching morphogenesis, and alveolar cell determination and maturation, then revise its involvement in NSCLC formation, progression and treatment refractoriness, particularly in the context of various mutational statuses associated with NSCLC, and, lastly, conclude by providing a succinct outlook of the therapeutic perspectives of Notch targeting in NSCLC therapy, including an overview on prospective synthetic lethality approaches.

Prognostic Value of KRAS Mutation Subtypes and PD-L1 Expression in Patients With Lung Adenocarcinoma

BACKGROUND

The prognostic value of different KRAS (Kirsten rat sarcoma viral oncogene) mutation subtypes and their association with programmed death ligand 1 (PD-L1) expression in lung adenocarcinoma (LADC) remain unclear. We examined the association of KRAS mutation subtypes with clinical outcomes and PD-L1 expression status.

PATIENTS AND METHODS

Patients diagnosed with KRAS-mutated LADC were evaluated for PD-L1 expression, cancer staging, overall survival (OS), and relapse-free survival.

RESULTS

A cohort of 254 KRAS-mutated LADC patients (median follow-up, 17 months) was studied. The 3 major subtypes of KRAS mutations were G12C (46.1%), G12V (21.7%), and G12D (15.7%). We found that all these subtypes had no impact on cancer stages, brain metastasis at diagnosis, OS, and relapse-free survival. Among this cohort, 33% of 94 patients who had PD-L1 staining data available had PD-L1-positive disease (≥ 1% of tumor cells). PD-L1 expression status was not significantly different among the 3 major mutation subtypes. Of interest, among patients with G12C mutation, positive PD-L1 expression was associated with significantly shorter OS (median survival, 5.7 vs. 12.8 months, P = .007). In multivariable analysis, PD-L1 positivity remained as an adverse factor for OS, with hazard ratio of 4.44 (P = .0007). PD-L1 status did not affect OS in other subtypes of mutations.

CONCLUSION

KRAS mutation subtype is not associated with patient clinical outcomes or PD-L1 expression status. However, PD-L1 positivity appears to negatively affect OS in LADC patients with G12C mutation. Further study is needed to confirm our observation and to determine if programmed cell death 1/PD-L1 antagonist may affect the clinical outcome of patients with different KRAS mutation subtypes.

A Real-World Study in Advanced Non-Small Cell Lung Cancer with KRAS Mutations

BACKGROUND

KRAS gene mutations are well known as a key driver of advanced non-small cell lung cancer (NSCLC). The impact of KRAS-mutant subtypes on the survival benefit from salvage chemotherapy is controversial. Here, we present a real-world study in patients across China with advanced NSCLC with KRAS mutations using a website-based patient self-report system.

METHODS

We identified a total of 75 patients diagnosed with KRAS-mutant (determined by molecular sequencing) advanced NSCLC between 2014/5/9 and 2019/5/30. KRAS mutation subtypes were divided into G12C and non-G12C groups for statistical analysis. The clinicopathological characteristics and treatment survival benefit in all patients with a KRAS mutation were evaluated. Programmed death-ligand 1 (PD-L1) expression data were collected from 30 patients in the same cohort.

RESULTS

In this study, 23 patients with stage IIIB NSCLC and 52 patients with stage IV NSCLC were enrolled with 58 men and 17 women; the median age was 60 years (39-84). All patients received regular chemotherapy/radiotherapy/targeted therapy/immune therapy as per the disease condition. Four main KRAS mutation subtypes were detected: G12C (33%), G12V (19%), G12A (12%), and G12D (12%). Three predominant KRAS comutations were detected: TP53-KRAS (31%), EGFR-KRAS (11%), and STK11-KRAS (8%). Compared with the KRAS non-G12C mutation subtype, patients with the KRAS G12C mutation had potentially longer progression-free survival (PFS) after first-line chemotherapy (4.7 vs. 2.5 months, p < 0.05). Pemetrexed-based chemotherapy appeared to be superior to taxanes- and gemcitabine-based chemotherapies in all patients (PFS: 5.0 vs. 1.5 and 2.3 months, respectively, p > 0.05). Cox regression analysis showed that the KRAS G12C mutation and pemetrexed-based first-line chemotherapy were positive influencers for PFS after first-line (hazard ratios = 0.31 and 0.55, respectively, P < 0.05), but not second-line chemotherapies.

CONCLUSION

The KRAS G12C mutation could be a predictive biomarker for better survival benefit from first-line chemotherapy in patients with advanced NSCLC and KRAS mutations. The first-line chemotherapy regimen could possibly influence the outcome in patients with KRAS mutations. Larger and prospective clinical trials are warranted to confirm our conclusions.

New Horizons in KRAS-Mutant Lung Cancer: Dawn After Darkness

In non-small cell lung cancer (NSCLC), the most frequent oncogenic mutation in western countries is KRAS, for which, however, there remains no clinically approved targeted therapies. Recent progress on high biological heterogeneity including diverse KRAS point mutations, varying dependence on mutant KRAS, wide spectrum of other co-occurring genetic alterations, as well as distinct cellular status across the epithelial-to-mesenchymal transition (EMT), has not only deepened our understanding about the pathobiology of KRAS-mutant NSCLC but also brought about unprecedented new hopes for precision treatment of patients. In this review, we provide an update on the most recent advances in KRAS-mutant lung cancer, with a focus on mechanistic insights into tumor heterogeneity, the potential clinic implications and new therapies on horizons tailored for KRAS-mutant lung cancer.

Clinical outcomes to pemetrexed-based versus non-pemetrexed-based platinum doublets in patients with KRAS-mutant advanced non-squamous non-small cell lung cancer

PURPOSE

KRAS mutation has been associated with enhanced dependency on the folate metabolism in preclinical studies. However, whether KRAS mutation correlates to increased sensitivity to pemetrexed in patients with advanced NSCLC is unknown.

METHODS

Patients with advanced non-squamous NSCLC who had a documented EGFR and ALK WT genotype with simultaneous KRAS mutation assessment were evaluated for clinical outcome to pemetrexed- and non-pemetrexed-based first-line platinum doublet according to KRAS mutation status.

RESULTS

Of 356 patients identified, 138 harbored a KRAS mutation. Among KRAS-mutant NSCLCs, those treated with platinum/pemetrexed (81/138) had significantly lower ORR (30.9% versus 47.4%, P = 0.05), DCR (51.8% versus 71.9%, P = 0.02) and shorter median progression-free survival [mPFS 4.1 versus 7.1 months, HR 1.48 (95% CI 1.03-2.12), P = 0.03] and median overall survival [mOS 9.7 versus 26.9 months, HR 1.93 (95% CI 1.27-2.94), P = 0.002] compared to those who received a non-pemetrexed-based platinum doublet (57/138). No difference in ORR, DCR, mPFS and mOS was observed between KRAS WT patients who received a pemetrexed-based (124/218) versus non-pemetrexed base platinum doublets (94/218). After adjusting for performance status, age and the presence of brain metastasis at baseline, treatment with pemetrexed-based platinum doublet was associated with an increased risk of death [HR 2.27 (95% CI 1.12-4.63), P = 0.02] among KRAS-mutant patients in multivariate analysis.

CONCLUSION

Patients with KRAS-mutant lung adenocarcinoma have a poorer outcome on pemetrexed-based first-line chemotherapy. Whether KRAS-mutant NSCLCs should be excluded from pemetrexed-containing regimens should be assessed prospectively.

Comparison of PANAMutyper and PNAClamp for Detecting KRAS Mutations from Patients With Malignant Pleural Effusion

BACKGROUND/AIM

KRAS is one of the frequently mutated genes in human cancers and often relates with drug resistance and poor prognosis. PANAMutyper™ is a novel technology that integrates PNAClamp™ and PANA S-Melting™. In the present study, PANAMutyper™ and PNAClamp™ were compared for the detection of KRAS mutations using different samples of patients with malignant pleural effusion.

PATIENTS AND METHODS

A total of 103 patients (including 56 lung adenocarcinoma, 10 lung squamous carcinoma, 17 small cell lung cancer, 3 large cell lung cancer, 3 stomach cancer, 2 ovarian cancer, and others) with malignant pleural effusion were investigated using matched tumor tissue, cell block, and pleural effusion samples. The diagnostic performance of these two methods was compared.

RESULTS

KRAS mutations were detected in 18 (17.5%) of 103 patients using tissue, cell block, and pleural effusion samples. All 18 patients with KRAS mutations were detected by PANAMutyper™ using any sample type, however, only 7 cases were detected by PNAClamp™. Among the subtypes of KRAS mutations, substitution in codon 12, 35G>T was the most frequent, followed by substitution in codon 12, 35G>A and codon 12, 34G>A. In pleural effusion specimens, PANAMutyper™ showed a better diagnostic performance compared to PNAClamp™.

CONCLUSION

PANAMutyper™ had a diagnostic superiority for the detection of KRAS mutations in patients with malignant pleural effusion compared to PNAClamp™, although there was a concordance between PANAMutyper™ and PNAClamp™ results. Therefore, PANAMutyper™ can be used for a more sensitive and accurate detection of KRAS mutations.

[Research Progress of KRAS Mutation in Non-small Cell Lung Cancer]

肺癌是全球癌症相关死亡的主要原因。非小细胞肺癌（non-small cell lung cancer, NSCLC）占所有肺癌患者中的80%-85%，大多数肺癌患者在确诊时已处于晚期阶段。目前，基于驱动基因的靶向治疗的发展改变了晚期NSCLC患者的治疗模式。在NSCLC中，表皮生长因子受体突变（epidermal growth factor receptor, EGFR）和棘皮动物微管相关蛋白和间变性淋巴瘤激酶（echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase, EML4-ALK）融合已被验证为强大的生物标志物。众所周知KRAS也是NSCLC中最常见的突变致癌基因之一，尽管20多年前在NSCLC中发现了KRAS突变，迄今为止用于治疗KRAS突变的NSCLC患者的药物有很多，但目前还没有针对直接消除KRAS活性的选择性和特异性抑制剂。此外具有KRAS突变的NSCLC患者对大多数系统性治疗的反应性差。然而使用靶向药物针对活化的信号通路个体化治疗对KRAS突变的NSCLC患者的预后有很好疗效。此外KRAS突变在NSCLC中的预后和预测作用尚不清楚。在这篇综述中，我们重点讨论了KRAS突变的NSCLC的研究进展，包括分子生物学、临床病理特征、KRAS突变的预后和预测等方面，进而有助于提高临床工作者对KRAS突变的NSCLC的认知。。

TTF-1 and EGFR expression are related to EGFR mutation in lung adenocarcinoma

Thyroid transcription factor-1 (TTF-1) is routinely used in the diagnosis of lung carcinoma and the subclassification of non-small cell lung cancer (NSCLC) in combination with other markers. The epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) are particularly effective in NSCLC patients harboring active EGFR mutations. EGFR protein is a poor prognostic factor for NSCLC patients. The relationship between TTF-1 expression and EGFR mutation and EGFR expression has not been well documented. The aim of this study was to investigate the relationship between TTF-1 and EGFR expression and mutation, and the clinical significance in lung adenocarcinoma. We analyzed TTF-1 expression, EGFR expression and mutation in 213 cases of lung adenocarcinoma. TTF-1 and EGFR expression levels were detected by immunohistochemical staining with monoclonal antibodies. EGFR mutations in exon 18, 19, 20 and 21 were assayed by the scorpion amplification refractory mutation system (ARMS) method. Forty-eight patients with EGFR mutations in exon 19 or 21 were detected from 91 patients with TTF-1 strong positive expression (3+) (52.74%), and 35 patients were detected with either exon 19 or 21 mutations from 54 patients with both TTF1 and EGFR positive expression (64.81%). Our data indicate that TTF-1 expression was positively related to EGFR mutation (P < 0.001) and EGFR expression (P < 0.001). EGFR expression level was positively related to its mutation (P = 0.003). These results indicate TTF-1 and EGFR positive lung adenocarcinomas frequently harbor EGFR mutations.

Drug Resistance in Non-Small Cell Lung Cancer: A Potential for NOTCH Targeting?

Drug resistance is a major cause for therapeutic failure in non-small cell lung cancer (NSCLC) leading to tumor recurrence and disease progression. Cell intrinsic mechanisms of resistance include changes in the expression of drug transporters, activation of pro-survival, and anti-apoptotic pathways, as well as non-intrinsic influences of the tumor microenvironment. It has become evident that tumors are composed of a heterogeneous population of cells with different genetic, epigenetic, and phenotypic characteristics that result in diverse responses to therapy, and underlies the emergence of resistant clones. This tumor heterogeneity is driven by subpopulations of tumor cells termed cancer stem cells (CSCs) that have tumor-initiating capabilities, are highly self-renewing, and retain the ability for multi-lineage differentiation. CSCs have been identified in NSCLC and have been associated with chemo- and radiotherapy resistance. Stem cell pathways are frequently deregulated in cancer and are implicated in recurrence after treatment. Here, we focus on the NOTCH signaling pathway, which has a role in stem cell maintenance in non-squamous non-small lung cancer, and we critically assess the potential for targeting the NOTCH pathway to overcome resistance to chemotherapeutic and targeted agents using both preclinical and clinical evidence.

Management of KRAS-Mutant Non-Small Cell Lung Cancer in the Era of Precision Medicine

OPINION STATEMENT

The discovery of genomic alterations that drive the development and progression of non-small cell lung cancer (NSCLC) has transformed how we treat metastatic disease. However, the promise of precision medicine remains elusive for the most commonly mutated oncogene in NSCLC, KRAS. This is perhaps due to the substantial heterogeneity within the broader genomic context of KRAS-mutant NSCLC. At this time, approaches for treating metastatic KRAS-mutant NSCLC mirror those for treating NSCLC that lacks a known driver mutation, including standard chemotherapeutic and immunotherapeutic approaches. Ongoing research aims to define further subgroups of KRAS-mutant NSCLC based on mutation subtype and co-occurring mutations. These efforts offer the potential to optimize standard-of-care regimens within these emerging subgroups and harness innovative strategies to realize precision medicine in this setting.