Spectrum of LKB1, EGFR, and KRAS mutations in chinese lung adenocarcinomas

Additional impact of genetic ancestry over race/ethnicity to prevalence of KRAS mutations and allele-specific subtypes in non-small cell lung cancer

The KRAS mutation is the most common oncogenic driver in patients with non-small cell lung cancer (NSCLC). However, a detailed understanding of how self-reported race and/or ethnicity (SIRE), genetically inferred ancestry (GIA), and their interaction affect KRAS mutation is largely unknown. Here, we investigated the associations between SIRE, quantitative GIA, and KRAS mutation and its allele-specific subtypes in a multi-ethnic cohort of 3,918 patients from the Boston Lung Cancer Survival cohort and the Chinese OrigiMed cohort with an independent validation cohort of 1,450 patients with NSCLC. This comprehensive analysis included detailed covariates such as age at diagnosis, sex, clinical stage, cancer histology, and smoking status. We report that SIRE is significantly associated with KRAS mutations, modified by sex, with SIRE-Asian patients showing lower rates of KRAS mutation, transversion substitution, and the allele-specific subtype KRASG12C compared to SIRE-White patients after adjusting for potential confounders. Moreover, GIA was found to correlate with KRAS mutations, where patients with a higher proportion of European ancestry had an increased risk of KRAS mutations, especially more transition substitutions and KRASG12D. Notably, among SIRE-White patients, an increase in European ancestry was linked to a higher likelihood of KRAS mutations, whereas an increase in admixed American ancestry was associated with a reduced likelihood, suggesting that quantitative GIA offers additional information beyond SIRE. The association of SIRE, GIA, and their interplay with KRAS driver mutations in NSCLC highlights the importance of incorporating both into population-based cancer research, aiming to refine clinical decision-making processes and mitigate health disparities.

The Abundance of KRAS and RAS Gene Mutations in Cancer

Mutant forms of the RAS genes KRAS, NRAS, and HRAS are important and common drivers of cancer. Recently, two independent teams that integrated cancer genomics with cancer epidemiology estimated that approximately 15-20% of all human cancers harbor a mutation in one of these three RAS genes. These groups also estimate KRAS mutations occur in 11-14% of all human cancers. Although these estimates are lower than many commonly encountered values, these estimates continue to rank KRAS and the ensemble of RAS oncogenes among the most common genetic drivers of cancer across all forms of malignancy.

Efficacy of metformin adjunctive therapy as the treatment for non-diabetic patients with advanced non-small cell lung cancer: A Systematic review and Meta-analysis

Background

Currently, the anticancer effects of metformin on different types of lung cancer have been frequently studied. However, the relationship between metformin and prognosis in nondiabetic patients with lung cancer remains controversial. To systematically evaluate the efficacy of metformin adjunctive therapy as the treatment for nondiabetic patients with advanced non-small cell lung cancer (NSCLC) to provide an evidence-based reference for clinical medication.

Materials and Methods

The literatures related to Phase II or III randomized controlled trials (RCTs) of metformin adjunctive therapy in nondiabetic patients with advanced NSCLC, including EMBASE, PubMed, the Cochrane Library, and Scopus database, were retrieved by computer, and the search time ranged from January 2017 to August 2022. The risk of bias assessment tool recommended by Cochrane Systematic Evaluator Manual 5.1.0 was used to evaluate the quality of the RCTs included. Rev Man 5.3 software and STATA15.0 were used for meta-analysis.

Results

A total of 8 studies were included (925 patients). Meta-analysis results showed that there were no significant differences in progression-free survival (PFS) (hazard ratio [HR] = 0.95, 95% confidence interval [CI]: 0.66-1.36, P = 0.77), overall survival (OS) (HR = 0.89, 95% CI: 0.61-1.30, P = 0.55, n =7), objective response rate (ORR) (odds ratio [OR] = 1.37, 95% CI: 0.76-2.46, P = 0.30), and 1-year PFS rate (OR = 0.87, 95% CI: 0.39-1.94, P = 0.73, n = 3). Sensitivity analysis showed that PFS and OS indexes were stable.

Conclusion

Metformin adjunctive therapy can improve the DCR of nondiabetic patients with advanced NSCLC. In addition, the patients cannot obtain a prolonged PFS, OS, 1-year PFS rate, and higher ORR rate.

Phe354Leu polymorphism of the liver kinase B1 gene as a prognostic factor in adult egyptian patients with acute myeloid leukemia

Background

The human liver kinase B1 (LKB1) gene is a significant tumor suppressor widely expressed in all fetal and adult tissues. Despite its established role in solid tumors, the biological and clinical implications of LKB1 gene alterations in hematological malignancies have not been sufficiently recognized.

Aim

This study aimed to determine the frequency of the LKB1 Phe354Leu polymorphism in adult Egyptian patients with cytogenetically normal AML (CN-AML), evaluate its clinical prognostic significance, and investigate its effect on the therapeutic outcome and patient survival.

Methods

Direct sequencing of amplified exon eight of the LKB1 gene was performed to detect the Phe354Leu polymorphism in 72 adult de novo CN-AML patients.

Results

The LKB1 Phe354Leu polymorphism was detected in 16.7% of patients and associated with younger age and lower hemoglobin levels (p < 0.001). Patients in the mutated group had significantly higher total leukocytic count and bone marrow blasts (p = 0.001 and p < 0.001, respectively). The most common FAB subtypes in mutated patients were M4 and M2. The relapse rate was significantly higher in the mutated group (p = 0.004). There was a significant association between the FLT3-ITD polymorphism and LKB1 F354L (p < 0.001). The mutated group had shorter overall survival (p = 0.003). In multivariate analysis, the Phe354Leu polymorphism was a significant independent prognostic variable for the overall and disease-free survival of the studied patients (p = 0.049).

Conclusion

The LKB1 Phe354Leu polymorphism was diagnosed at younger ages in Egyptian CN-AML patients and represented a poor independent prognostic factor in CN-AML. Patients who carried this polymorphism had shorter overall survival and more frequent relapses. Our findings may provide insight into the design of therapeutic targets, and molecular testing of the LKB1 gene is recommended for proper risk stratification of CN-AML patients.

Prevalence, clinical and molecular characteristics of early stage EGFR-mutated lung cancer in a real-life West-European cohort: Implications for adjuvant therapy

OBJECTIVES

The landmark ADAURA study recently demonstrated a significant disease-free survival benefit of adjuvant osimertinib in patients with resected EGFR-mutated lung adenocarcinoma. However, data on prevalence rates and stage distribution of EGFR mutations in non-small cell lung cancer in Western populations are limited since upfront EGFR testing in early stage lung adenocarcinoma is not common practice. Here, we present a unique, real-world, unselected cohort of lung adenocarcinoma to aid in providing a rationale for routine testing of early stage lung cancers for EGFR mutations in the West-European population.

MATERIAL AND METHODS

We performed routine unbiased testing of all cases, regardless of TNM stage, with targeted next-generation sequencing on 486 lung adenocarcinoma cases between 01- January 2014 and 01 February 2020. Clinical and pathological data, including co-mutations and morphology, were collected. EGFR-mutated cases were compared to KRAS-mutated cases to investigate EGFR-specific characteristics.

RESULTS

In total, 53 of 486 lung adenocarcinomas (11%) harboured an EGFR mutation. In early stages (stage 0-IIIA), the prevalence was 13%, versus 9% in stage IIIB-IV. Nine out of 130 (7%) stage IB-IIIA patients fit the ADAURA criteria. Early stage cases harboured more L858R mutations (p = 0.02), fewer exon 20 insertions (p = 0.048), fewer TP53 co-mutations (p = 0.007), and were more frequently never smokers (p = 0.04) compared to late stage cases with EGFR mutations. The KRAS-mutated cases were distributed more evenly across TNM stages compared to the EGFR-mutated cases.

CONCLUSION

As (neo-)adjuvant targeted therapy regimes enter the field of lung cancer treatment, molecular analysis of early stage non-small cell lung cancer becomes relevant. Testing for EGFR mutations in early stage lung adenocarcinoma holds a substantial yield in our population, as our number needed to test ratio for adjuvant osimertinib was 14.4. The observed differences between early and late stage disease warrant further analysis to work towards better prognostic stratification and more personalised treatment.

Evaluating Real World Mutational Differences Between Hispanics and Asians in NSCLC at a Large Academic Institution in Los Angeles

INTRODUCTION

Hispanics living in the United States have higher rates of Epidermal Growth Factor Receptor (EGFR) mutations compared with Non-Hispanic Whites. While this higher incidence is like Asian patients living in the United States, the outcomes for Hispanic patients differ. We looked to compare the variances in mutational profiles between Hispanics and Asians in Los Angeles.

PATIENTS AND METHODS

Three hundred ninety three non-small cell lung cancer (NSCLC) patients treated at Los Angeles County + University of Southern California (LAC + USC) Medical Center and Norris Comprehensive Cancer Center who received comprehensive genomic profiling (CGP) were evaluated from July 2017 to August 2020. CGP was done using tissue biopsies (n = 211) from Caris Life Sciences and liquid biopsies (n = 231) from Guardant Health. Multivariate logistic regression evaluated the role of race between Hispanics and Asians.

RESULTS

In the Hispanic cohort (n = 90), 50.0% were male, median age of diagnosis was 62, 54.5% were non-smokers, and 85.5% had adenocarcinoma. In Asians (n = 142), 47.5% were male, median age of diagnosis was 65, 59.6% were non-smokers, and 83.8% had adenocarcinoma. Hispanic patients had greater prevalence of Kirsten rat sarcoma virus (KRAS) mutations (odds ratio [OR] 4.42, 95% confidence interval [95% CI]: 1.63-12.83) and lesser prevalence of EGFR mutations (OR 0.31, 95% CI: 0.16-0.59). There were a greater proportion of Hispanic smokers with KRAS mutations (14/41; 34.1%) than Asian smokers (4/58; 6.9%).

CONCLUSION

We saw a greater percentage of Hispanics with KRAS mutations despite similar smoking percentages along with a greater percentage of Asians with EGFR mutations. This study shows that ethnic and racial backgrounds of the patient can influence the effects of potentially carcinogenic exposures leading to variances of mutation frequency of NSCLC among different ethnicities.

Characterization With KRAS Mutant Is a Critical Determinant in Immunotherapy and Other Multiple Therapies for Non-Small Cell Lung Cancer

Non-small cell lung cancer (NSCLC) is a frequent type of cancer, which is mainly characterized clinically by high aggressiveness and high mortality. KRAS oncoprotein is the most common molecular protein detected in NSCLC, accounting for 25% of all oncogenic mutations. Constitutive activation of the KRAS oncoprotein triggers an intracellular cascade in cancer cells, leading to uncontrolled cell proliferation of cancer cells and aberrant cell survival states. The results of multiple clinical trials have shown that different KRAS mutation subtypes exhibit different sensitivities to different chemotherapy regimens. Meanwhile, anti-angiogenic drugs have shown differential efficacy for different subtypes of KRAS mutated lung cancer. It was explored to find if the specificity of the KRAS mutation subtype would affect PD-L1 expression, so immunotherapy would be of potential clinical value for the treatment of some types of KRAS mutations. It was discovered that the specificity of the KRAS mutation affected PD-L1, which opened up immunotherapy as a potential clinical treatment option. After several breakthrough studies, the preliminary test data of many early clinical trials showed that it is possible to directly inhibit KRAS G12C mutation, which has been proved to be a targeted treatment that is suitable for about 10%-12% of patients with advanced NSCLC, having a significant impact on the prolongation of their survival and the improvement of their quality of life. This article reviews the latest progress of treatments for NSCLC with KRAS mutation, in order to gain insight into the biological diversity of lung cancer cells and their potential clinical implications, thereby enabling individualized treatment for patients with KRAS-mutant NSCLC.

Histologic Transformation in EGFR-Mutant Lung Adenocarcinomas: Mechanisms and Therapeutic Implications

With the advent of potent EGFR tyrosine kinase inhibitors (TKIs), the treatment landscape of EGFR-mutant lung adenocarcinomas has changed drastically in recent years. However, the development of resistance to EGFR TKIs remains a critical barrier to improving survival in these patients. Histologic transformations to small cell lung carcinoma, large cell neuroendocrine carcinoma, squamous cell carcinoma, and the sarcomatoid phenotype have been increasingly recognized as important mechanisms of resistance. In this article, we summarize the known biological bases for such phenotypic switches in regard to EGFR TKIs and describe novel pathways that might be harnessed to develop effective novel therapies for patients with EGFR-mutant non-small cell lung cancers.

New Scope of Targeted Therapies in Lung Carcinoma

Lung cancer (LC) is the leading cause of cancer deaths worldwide. Recent research has also shown LC as a genomic disease, causing somatic mutations in patients. Tests related to mutational analysis and genome profiles have lately expanded significantly in the genetics/genomics field of LC. This review summarizes the current knowledge about different signalling pathways of LC based on the clinical impact of molecular targets. It describes the main molecular pathways and changes involved in the development, progression, and cellular breakdown of LC and the molecular changes. This review focuses on approved and targeted experimental therapies such as immunotherapy and clinical trials that examine the different targeted approaches to treating LC. We aimto clarify the differences in the extent of various genetic mutations in several areas for LC patients. Targeted molecular therapies for LC can be continued with advanced racial differences in genetic changes, which have a significant impact on the choice of drug treatment and our understanding of the profile of drug susceptibility/resistance. The most relevant genes described in this review are EGFR, KRAS, MET, BRAF, PIK3CA, STK11, ERBB3, PTEN, and RB1. Combined research efforts in this field are required to understand the genetic difference in LC outcomes in the future.

Efficacy of immunotherapy in KRAS-mutant non-small-cell lung cancer with comutations

KRAS-mutant non-small-cell lung cancer is the most common molecular driver of lung adenocarcinoma in western populations. No KRAS specific therapy has been approved by the US FDA until 2021. Despite significant heterogeneity in comutations, patients typically receive single-agent immunotherapy or chemoimmunotherapy as standard first-line therapy. It is unclear whether KRAS mutations predict outcomes with immunotherapy; however, there is emerging data suggesting improved outcomes in patients with a TP53 comutation and worse outcomes in patients with a STK11/LKB1 or KEAP1 comutation.

Nanog maintains stemness of Lkb1-deficient lung adenocarcinoma and prevents gastric differentiation

Growing evidence supports that LKB1-deficient KRAS-driven lung tumors represent a unique therapeutic challenge, displaying strong cancer plasticity that promotes lineage conversion and drug resistance. Here we find that murine lung tumors from the KrasLSL-G12D/+ ; Lkb1flox/flox (KL) model show strong plasticity, which associates with up-regulation of stem cell pluripotency genes such as Nanog. Deletion of Nanog in KL model initiates a gastric differentiation program and promotes mucinous lung tumor growth. We find that NANOG is not expressed at a meaningful level in human lung adenocarcinoma (ADC), as well as in human lung invasive mucinous adenocarcinoma (IMA). Gastric differentiation involves activation of Notch signaling, and perturbation of Notch pathway by the γ-secretase inhibitor LY-411575 remarkably impairs mucinous tumor formation. In contrast to non-mucinous tumors, mucinous tumors are resistant to phenformin treatment. Such therapeutic resistance could be overcome through combined treatments with LY-411575 and phenformin. Overall, we uncover a previously unappreciated plasticity of LKB1-deficient tumors and identify the Nanog-Notch axis in regulating gastric differentiation, which holds important therapeutic implication for the treatment of mucinous lung cancer.

AMPKα-like proteins as LKB1 downstream targets in cell physiology and cancer

One of the key events in cancer development is the ability of tumor cells to overcome nutrient deprivation and hypoxia. Among proteins performing metabolic adaptation to the various cellular nutrient conditions, liver kinase B 1 (LKB1) and its main downstream target adenosine monophosphate (AMP)-activated protein kinase α (AMPKα) are important sensors of energy requirements within the cell. Although LKB1 was originally described as a tumor suppressor, given its role in metabolism, it potentially acts as a double-edged sword. AMPKα, a master regulator of cell energy demands, is activated when ATP level drops under a certain threshold, responding accordingly through its downstream targets. Twelve downstream kinase targets of LKB1 have been described as AMPKα-like proteins. This group is comprised of novel (nua) kinase family (NUAK) kinases (NUAK1 and 2) linked to cell cycle progression and ultraviolet (UV)-damage; microtubule affinity regulating kinases (MARKs) (MARK1, MARK2, MARK3, and MARK4) that are involved in cell polarity; salt inducible kinases (SIK) (SIK1, SIK2, also known as Qin-induced kinase or QIK and SIK3) that are implicated in cell metabolism and adipose tissue development and mitotic regulation; maternal embryonic leuzine zipper kinase (MELK) that regulate oocyte maturation; and finally brain selective kinases (BRSKs) (BRSK1 and 2), which have been mainly characterized in the brain due to their role in neuronal polarization. Thus, many efforts have been made in order to harness LKB1 kinase and its downstream targets as a possible therapeutic hub in tumor development and propagation. In this review, we describe LKB1 and its downstream target AMPK summarize major functions of various AMPK-like proteins, while focusing on biological functions of BRSK1 and 2 in different models.

The evolving landscape of biomarker testing for non-small cell lung cancer in Europe

The discovery of oncogenic driver mutations rendering non-small cell lung cancer (NSCLC) targetable by small-molecule inhibitors, and the development of immunotherapies, have revolutionised NSCLC treatment. Today, instead of non-selective chemotherapies, all patients with advanced NSCLC eligible for treatment (and increasing numbers with earlier, less extensive disease) require fast and comprehensive screening of biomarkers for first-line patient selection for targeted therapy, chemotherapy, or immunotherapy (with or without chemotherapy). To avoid unnecessary re-biopsies, biomarker screening before first-line treatment should also include markers that are actionable from second-line onwards; PD-L1 expression testing is also mandatory before initiating treatment. Population differences exist in the frequency of oncogenic driver mutations: EGFR mutations are more frequent in Asia than Europe, whereas the converse is true for KRAS mutations. In addition to approved first-line therapies, a number of emerging therapies are being investigated in clinical trials. Guidelines for biomarker testing vary by country, with the number of actionable targets and the requirement for extensive molecular screening strategies expected to increase. To meet diagnostic demands, rapid screening technologies for single-driver mutations have been implemented. Improvements in DNA- and RNA-based next-generation sequencing technologies enable analysis of a group of genes in one assay; however, turnaround times remain relatively long. Consequently, rapid screening technologies are being implemented alongside next-generation sequencing. Further challenges in the evolving landscape of biomarker testing in NSCLC are actionable primary and secondary resistance mechanisms to targeted therapies. Therefore, comprehensive testing on re-biopsies, collected at the time of disease progression, in combination with testing of circulating tumour DNA may provide important information to guide second- or third-line therapies. Furthermore, longitudinal biomarker testing can provide insights into tumour evolution and heterogeneity during the course of the disease. We summarise best practice strategies for Europe in the changing landscape of biomarker testing at diagnosis and during treatment.

Cigarette smoke-induced LKB1/AMPK pathway deficiency reduces EGFR TKI sensitivity in NSCLC

Smoker patients with non-small cell lung cancer (NSCLC) have poorer prognosis and survival than those without smoking history. However, the mechanisms underlying the low response rate of those patients to EGFR tyrosine kinase inhibitors (TKIs) are not well understood. Here we report that exposure to cigarette smoke extract enhances glycolysis and attenuates AMP-activated protein kinase (AMPK)-dependent inhibition of mTOR; this in turn reduces the sensitivity of NSCLC cells with wild-type EGFR (EGFR^WT) to EGFR TKI by repressing expression of liver kinase B1 (LKB1), a master kinase of the AMPK subfamily, via CpG island methylation. In addition, LKB1 expression is correlated positively with sensitivity to TKI in patients with NSCLC. Moreover, combined treatment of EGFR TKI with AMPK activators synergistically increases EGFR TKI sensitivity. Collectively, the current study suggests that LKB1 may serve as a marker to predict EGFR TKI sensitivity in smokers with NSCLC carrying EGFR^WT and that the combination of EGFR TKI and AMPK activator may be a potentially effective therapeutic strategy against NSCLC with EGFR^WT.

KRAS G12C mutations in Asia: a landscape analysis of 11,951 Chinese tumor samples

Background

Kirsten rat sarcoma vial oncogene (KRAS) is one of the most prevalent oncogenes in multiple cancer types, but the incidence is different between the Asian and non-Asian populations. The recent development of KRAS G12C targeting drug has shown great promise. It is thus important to understand the genomic landscape of KRAS G12C in a specific population.

Methods

Sequencing data of 11,951 tumor samples collected from 11/2016 to 7/2019 from multiple centres in China were analyzed for KRAS mutation status. Concomitant genomic aberrations were further analyzed in tumors with KRAS G12C mutations, which were sequenced with comprehensive cancer panel including over 450 cancer-related genes. Smoking status and its correlation with KRAS were analyzed in 2,235 lung cancer cases within this cohort.

Results

KRAS mutations were identified in 1978 (16.6%) patient samples. Specifically, KRAS G12C accounted for 14.5% (n=286) of all KRAS mutations. G12C was most commonly seen in lung cancer (4.3%), followed by colorectal cancer (2.5%) and biliary cancer (2.3%). Almost all patients (99.6%) with G12C mutations had concomitant genomic aberrations. These were most commonly associated with the RAS/RTK pathway including BRAF and PI3KCA mutations. Moreover, KRAS mutation was positively correlated with smoking status in lung adenocarcinomas.

Conclusions

The overall incidence of KRAS G12C mutations remains low in the Chinese population. The most common tumor types harboring KRAS G12C mutations are in patients suffering from lung, colorectal and biliary cancers.

KRASQ61H Preferentially Signals through MAPK in a RAF Dimer-Dependent Manner in Non-Small Cell Lung Cancer

Assembly of RAS molecules into complexes at the cell membrane is critical for RAS signaling. We previously showed that oncogenic KRAS codon 61 mutations increase its affinity for RAF, raising the possibility that KRAS^Q61H, the most common KRAS mutation at codon 61, upregulates RAS signaling through mechanisms at the level of RAS assemblies. We show here that KRAS^Q61H exhibits preferential binding to RAF relative to PI3K in cells, leading to enhanced MAPK signaling in in vitro models and human NSCLC tumors. X-ray crystallography of KRAS^Q61H:GTP revealed that a hyperdynamic switch 2 allows for a more stable interaction with switch 1, suggesting that enhanced RAF activity arises from a combination of absent intrinsic GTP hydrolysis activity and increased affinity for RAF. Disruption of KRAS^Q61H assemblies by the RAS oligomer-disrupting D154Q mutation impaired RAF dimerization and altered MAPK signaling but had little effect on PI3K signaling. However, KRAS^Q61H oligomers but not KRAS^G12D oligomers were disrupted by RAF mutations that disrupt RAF-RAF interactions. KRAS^Q61H cells show enhanced sensitivity to RAF and MEK inhibitors individually, whereas combined treatment elicited synergistic growth inhibition. Furthermore, KRAS^Q61H tumors in mice exhibited high vulnerability to MEK inhibitor, consistent with cooperativity between KRAS^Q61H and RAF oligomerization and dependence on MAPK signaling. These findings support the notion that KRAS^Q61H and functionally similar mutations may serve as predictive biomarkers for targeted therapies against the MAPK pathway. SIGNIFICANCE: These findings show that oncogenic KRAS^Q61H forms a cooperative RAS-RAF ternary complex, which renders RAS-driven tumors vulnerable to MEKi and RAFi, thus establishing a framework for evaluating RAS biomarker-driven targeted therapies.

Understanding Lineage Plasticity as a Path to Targeted Therapy Failure in EGFR-Mutant Non-small Cell Lung Cancer

Somatic alterations in the epidermal growth factor receptor gene (EGFR) result in aberrant activation of kinase signaling and occur in ∼15% of non-small cell lung cancers (NSCLC). Patients diagnosed with EGFR-mutant NSCLC have good initial clinical response to EGFR tyrosine kinase inhibitors (EGFR TKIs), yet tumor recurrence is common and quick to develop. Mechanisms of acquired resistance to EGFR TKIs have been studied extensively over the past decade. Great progress has been made in understanding two major routes of therapeutic failure: additional genomic alterations in the EGFR gene and activation of alternative kinase signaling (so-called “bypass activation”). Several pharmacological agents aimed at overcoming these modes of EGFR TKI resistance are FDA-approved or under clinical development. Phenotypic transformation, a less common and less well understood mechanism of EGFR TKI resistance is yet to be addressed in the clinic. In the context of acquired EGFR TKI resistance, phenotypic transformation encompasses epithelial to mesenchymal transition (EMT), transformation of adenocarcinoma of the lung (LUAD) to squamous cell carcinoma (SCC) or small cell lung cancer (SCLC). SCLC transformation, or neuroendocrine differentiation, has been linked to inactivation of TP53 and RB1 signaling. However, the exact mechanism that permits lineage switching needs further investigation. Recent reports indicate that LUAD and SCLC have a common cell of origin, and that trans-differentiation occurs under the right conditions. Options for therapeutic targeting of EGFR-mutant SCLC are limited currently to conventional genotoxic chemotherapy. Similarly, the basis of EMT-associated resistance is not clear. EMT is a complex process that can be characterized by a spectrum of intermediate states with diverse expression of epithelial and mesenchymal factors. In the context of acquired resistance to EGFR TKIs, EMT frequently co-occurs with bypass activation, making it challenging to determine the exact contribution of EMT to therapeutic failure. Reversibility of EMT-associated resistance points toward its epigenetic origin, with additional adjustments, such as genetic alterations and bypass activation, occurring later during disease progression. This review will discuss the mechanistic basis for EGFR TKI resistance linked to phenotypic transformation, as well as challenges and opportunities in addressing this type of targeted therapy resistance in EGFR-mutant NSCLC.

Use of biomarker testing in lung cancer among Puerto Rico and Florida Physicians: Results of a comparative study

BACKGROUND

Lung cancer biomarker-driven therapies are the gold standard of treatment and recent studies suggest a higher prevalence of specific targetable biomarkers among Hispanic/Latinos (H/L) than Non-Hispanic Whites (NHW). The study aimed (1) to identify Florida (FL) and Puerto Rico (PR) physicians' knowledge and perceived value of newer genomic data regarding race/ethnicity in relation to optimal lung cancer treatment and survival; and (2) to identify modifiable practice barriers both across and within each location regarding biomarker testing in lung cancer.

METHODS

A 25-item survey was administered to a stratified random sample of physicians in FL and PR (medical oncologists, radiation oncologists, pulmonologists, and pathologists). Questions targeted domains of biomarker knowledge, attitudes toward testing, barriers, and practice behaviors regarding lung cancer biomarker testing.

RESULTS

The response rate was 45%. Participants identified guiding treatment decisions (82%) and personalizing treatments for patients (78%) as key benefits to mutation testing. PR physicians were more likely (p=0.022) to believe H/L had an elevated incidence of targetable epidermal growth factor receptor (EGFR) mutations compared to NHW. They also perceived lack of appropriate testing resources as a primary barrier compared to FL physicians (43.6% vs. 20.6%, p<0.001), whereas FL physicians identified mutation tests not conducted routinely as part of patient diagnosis as a primary barrier (43.1% vs 24.2%, p= 0.008).

CONCLUSIONS

Practice behaviors differed by specialty and between locations, and differences were noted concerning physician's preferences for ordering mutation testing, indicating a clear need for education among physicians in both locations.

IMPACT

Educating physicians regarding biomarker testing is imperative to improve patient care.

Combination of Metformin and Gefitinib as First-Line Therapy for Nondiabetic Advanced NSCLC Patients with EGFR Mutations: A Randomized, Double-Blind Phase II Trial

PURPOSE

Preclinical and retrospective studies suggested a role for metformin in sensitizing patients who have diabetes with non-small cell lung cancer (NSCLC) to EGFR tyrosine kinase inhibitors (TKIs). We therefore examined its effects in combination with gefitinib in patients without diabetes harboring EGFR mutations (EGFRm).

PATIENTS AND METHODS

A total of 224 patients without diabetes with treatment-naïve stage IIIB-IV EGFRm NSCLC were randomly assigned in a 1:1 ratio to receive gefitinib plus either metformin or placebo. The primary endpoint was progression-free survival (PFS) rate at 1 year and secondary endpoints included overall survival (OS), PFS, objective response rate (ORR), and safety. Serum levels of IL6 were also examined in an exploratory analysis.

RESULTS

The median duration of follow-up was 19.15 months. The estimated 1-year PFS rates were 41.2% [95% confidence interval (CI), 30.0-52.2] with gefitinib plus metformin and 42.9% (95% CI, 32.6-52.7) with gefitinib plus placebo (P = 0.6268). Median PFS (10.3 months vs. 11.4 months) and median OS (22.0 months vs. 27.5 months) were numerically lower in the metformin group, while ORRs were similar between the two arms (66% vs. 66.7%). No significant treatment group differences were detected across all subgroups with respect to PFS, including those with elevated levels of IL6. Metformin combined with gefitinib resulted in a remarkably higher incidence of diarrhea compared with the control arm (78.38% vs. 43.24%).

CONCLUSIONS

Our study showed that addition of metformin resulted in nonsignificantly worse outcomes and increased toxicity and hence does not support its concurrent use with first-line EGFR-TKI therapy in patients without diabetes with EGFRm NSCLC.

Oncogenic driver mutations in Swiss never smoker patients with lung adenocarcinoma and correlation with clinicopathologic characteristics and outcome

PURPOSE

Lung cancer in never smokers is recognized as a distinct molecular, clinicopathologic and epidemiologic entity. The aim of the study was to investigate the molecular profile in Swiss never smokers with lung adenocarcinoma and to correlate the mutation status with clinicopathologic and demographic patient characteristics and outcome.

METHODS

One hundred thirty-eight never smokers diagnosed with lung adenocarcinoma at the University Hospital Zurich between 2011-2018 were included in the study. Data from the electronic medical records were reviewed to characterize clinicopathologic and demographic features, molecular profile, treatment and outcome.

RESULTS

The majority of patients were female (58.7%) with a median age at diagnosis of 64.5 years (range, 27.1-94.2 years). The most common mutations were EGFR (58.7%) followed by ALK (12.3%), TP53 (5.8%), MET (5.8%), KRAS (4.3%), ERBB2 (4.3%), PIK3CA (2.9%), BRAF (2.2%), ROS1 (1.4%), RET (1.4%), CTNNB1 (0.7%), PARP1 (0.7%), TET1 (0.7%) and PIK3CG (0.7%). Median overall survival (mOS) was 51.0 months (mo). Early clinical stage (p = 0.002) and treatment with targeted therapy (HR 2.53, 95% CI 1.35-4.74, p = 0.004) were independently associated with longer mOS. Patients with oncogenic driver mutations had significantly longer mOS (52.2 mo) compared to patients without mutations (16.9 mo) (HR 3.38, 95% CI 1.52-7.55, p = 0.003). Besides, patients with EGFR mutated (57.8 mo) or ALK rearranged (59.9 mo) tumors had significantly longer mOS compared to the EGFR wildtype (35.0 mo), ALK wildtype (46.5 mo) and pan-negative (16.9 mo) cohorts (HR 2.35, 95% CI 1.37-4.04, p = 0.002; HR 7.80, 95% CI 3.28-18.55, p < 0.001; HR 3.96, 95% CI 1.21-12.95, p = 0.023 and HR 34.78, 95% CI 3.48-34.65, p = 0.003).

CONCLUSION

Never smokers with lung adenocarcinoma display distinct clinicopathologic and molecular features and are characterized by a high incidence of targetable mutations. Never smokers with targetable mutations have significantly longer survival compared to patients without mutations.

Loss of FGL1 induces epithelial‑mesenchymal transition and angiogenesis in LKB1 mutant lung adenocarcinoma

Liver kinase b1 (LKB1) is a tumor suppressor, and the inactivated mutation frequency of LKB1 in lung adenocarcinoma is ~20%. The present study aimed to explore potential novel biomarkers in LKB1 mutant lung adenocarcinoma. Gene expression data from lung adenocarcinoma patients were downloaded from The Cancer Genome Atlas and the Gene Expression Omnibus databases. R software was used to analyze the gene expression profiles. Reverse transcription‑quantitative PCR (RT‑qPCR), western blot and immunohistochemistry (IHC) analyses were used to examine gene expression and function. Gene function was further explored via gene set enrichment analysis. A colony formation assay was used to evaluate cell proliferation. A wound‑healing assay and immunofluorescence analysis were used to evaluate cell migration and epithelial‑mesenchymal transition (EMT), respectively. Wound healing assay, immunofluorescence, western blot, RT‑qPCR and IHC results for EMT‑associated markers demonstrated that a loss of fibrinogen‑like 1 (FGL1) induced EMT in LKB1 mutant lung adenocarcinoma. RT‑qPCR and IHC analyses of angiogenesis‑related markers revealed that loss of FGL1 promoted angiogenesis in LKB1 mutant lung adenocarcinoma. Overall, the present results demonstrated that loss of FGL1 induced EMT and angiogenesis in LKB1 mutant lung adenocarcinoma. FGL1 may be a novel biomarker to indicate EMT and angiogenesis in patients with LKB1 mutant lung adenocarcinoma.

Analysis of Genetic Alterations in Tunisian Patients with Lung Adenocarcinoma

The identification of the mutations that drive lung cancer have furnished new targets for the treatment of non-small cell lung cancer (NSCLC) and led to the development of targeted therapies such as tyrosine kinase inhibitors that are used to combat the molecular changes promoting cancer progression. Furthermore, biomarkers identified from gene analysis can be used to detect early lung cancer, determine patient prognosis, and monitor response to therapy. In the present study we analyzed the molecular profile of seventy-three Tunisian patients with lung adenocarcinoma (LAD). Mutational analyses for EGFR and KRAS were performed using direct sequencing, immunohistochemistry or MassARRAY. Anaplastic lymphoma kinase (ALK) rearrangement was evaluated by immunohistochemistry using the D5F3 clone, and p53 expression was also assessed. The median age of patients at diagnosis was 61 years (range 23-82 years). Using different methodologies, EGFR mutations were found in 5.47% of patients and only exon 19 deletions "E746-A750 del" were detected. KRAS mutations were present in 9.58% of cases, while only one patient was ALK-positive. Moreover, abnormal immunostaining of p53 was detected in 56.16% of patients. In conclusion, the detected rates of EGFR and KRAS mutation and ALK rearrangement were lower than those found in European and Asian countries, whereas, abnormal p53 expression was slightly more frequent. Furthermore, given the small sample size of this study, a more comprehensive analysis of this patient set is warranted.

Analysis of the frequency of oncogenic driver mutations and correlation with clinicopathological characteristics in patients with lung adenocarcinoma from Northeastern Switzerland

BACKGROUND

Molecular testing of lung adenocarcinoma for oncogenic driver mutations has become standard in pathology practice. The aim of the study was to analyze the EGFR, KRAS, ALK, RET, ROS1, BRAF, ERBB2, MET and PIK3CA mutational status in a representative cohort of Swiss patients with lung adenocarcinoma and to correlate the mutational status with clinicopathological patient characteristics.

METHODS

All patients who underwent molecular testing of newly diagnosed lung adenocarcinoma during a 4-year period (2014-2018) were included. Molecular analyses were performed with Sanger sequencing (n = 158) and next generation sequencing (n = 311). ALK, ROS1 and RET fusion gene analyses were also performed with fluorescence in situ hybridization and immunohistochemistry/immunocytochemistry. Demographic and clinical data were obtained from the medical records.

RESULTS

Of 469 patients with informative EGFR mutation analyses, 90 (19.2%) had EGFR mutations. KRAS mutations were present in 33.9% of the patients, while 6.0% of patients showed ALK rearrangement. BRAF, ERBB2, MET and PIK3CA mutations and ROS1 and RET rearrangements were found in 2.6%, 1.9%, 1.9%, 1.5%, 1.7% and 0.8% of the patients, respectively. EGFR mutation was significantly associated with female gender and never smoking status. ALK translocations were more frequent in never smokers, while KRAS mutations were more commonly found in ever smokers. The association between KRAS mutational status and female gender was statistically significant only on multivariate analysis after adjusting for smoking.

CONCLUSION

The EGFR mutation rate in the current study is among the higher previously reported mutation rates, while the frequencies of KRAS, BRAF, ERBB2 and PIK3CA mutations and ALK, ROS1 and RET rearrangements are similar to the results of previous reports. EGFR and KRAS mutations were significantly associated with gender and smoking. ALK rearrangements showed a significant association with smoking status alone.

Auranofin Enhances Ibrutinib's Anticancer Activity in EGFR-Mutant Lung Adenocarcinoma

We previously found that ibrutinib has anticancer activity in EGFR-mutant non-small cell lung cancer (NSCLC). One of our recent studies showed that auranofin, a gold complex that has been used to treat rheumatoid arthritis, inhibited the PI3K/AKT/mTOR pathway and promoted apoptosis in some NSCLC cells. Because the PI3K/AKT/mTOR pathway is one of the major downstream pathways of EGFR, we hypothesized that ibrutinib's activity might be enhanced by combination therapy with auranofin in NSCLC cells. To this end, we examined ibrutinib's dose responses in EGFR-mutant H1975, PC9, and H1650 cells and in EGFR wild-type Calu3 and H460 cells in the presence or absence of auranofin. Although low concentrations of auranofin alone demonstrated mild anticancer activities, its presence dramatically enhanced ibrutinib's activity in H1975, PC9, and H1650 cells (IC₅₀ value reduced 10- to 100-fold), but had only mild effect on Calu3 and H460 cells, demonstrating that ibrutinib's anti-EGFR activity is enhanced when it is combined with auranofin. A mechanistic analysis revealed that ibrutinib alone induced dramatic inhibition of the MEK/ERK pathway in both H1975 and H1650 cells, whereas auranofin alone inhibited the AKT/mTOR pathway. The combination of ibrutinib and auranofin led to a dramatically enhanced inhibition of the expression or phosphorylation of multiple key nodes in the AKT/mTOR and MEK/ERK pathways in both cell lines. In mice, the combination of ibrutinib and auranofin significantly suppressed the growth of H1975 xenografted tumors without inducing obvious toxic effects. Our results demonstrate the feasibility of improving ibrutinib's anti-EGFR activity for NSCLC using combination therapy with auranofin. Mol Cancer Ther; 17(10); 2156-63. ©2018 AACR.

Liver kinase B1 suppresses growth of lung cancer cells through sonic hedgehog signaling pathway

Lung cancer is one of life-threatening cancers in the worldwide. Liver kinase B1 (LKB1) has been reported to be closely related to cancers; however, the underlying mechanism of LKB1 in lung cancer remains unclear. In our study, a LKB1 specific shRNA was employed to down-regulate LKB1 levels and a LKB1 over-expression plasmid was constructed to up-regulate LKB1 levels. Thereafter, growth of lung cancer cells was assessed by MTT assay and flow cytometry. Effects of LKB1 on the activation of sonic hedgehog (Shh) signaling pathway were detected by Western blot. Effects of LKB1 on lung cancer growth and Shh signaling pathway activation were also assessed in vivo. Our results showed that LKB1 inhibited proliferation of lung cancer cells and induced their apoptosis. Moreover, LKB1 inhibited Shh signaling pathway activation. Our in vivo study also showed that LKB1 inhibited lung cancer growth in vivo and modulated Shh signaling pathway. Treatment with cyclopamine, a Shh signaling pathway inhibitor, reversed the effects of LKB1 silencing and enhanced the effects of LKB1 over-expression. Results of our study demonstrate that LKB1 inhibits lung cancer growth in vitro and in vivo through Shh signaling pathway.

A novel BMX variant promotes tumor cell growth and migration in lung adenocarcinoma

The non-receptor tyrosine kinase BMX has been reported in several solid tumors. However, the alternative splicing of BMX and its clinical relevance in lung cancer remain to be elucidated. Exon1.0 array was used to identify a novel alternative splicing of BMX, BMXΔN, which was confirmed by rapid amplification of cDNA ends and reverse transcription-polymerase chain reaction. BMXΔN, resulting from exon skipping with excluding exon 1 to exon 8 of BMX gene, was found in 12% human lung adenocarcinoma specimens. BMXΔN is not found in paired pathologically normal lungs and positively correlated with EGFR mutation in lung adenocarcinomas. Moreover, BMXΔN increases cell proliferation, neoplastic transformation, and migratory property of human non-small cell lung cancer cells. The function of BMXΔN in lung cancer might be presumably due to enhanced ERK signaling.

Epidermal growth factor receptor mutation-guided treatment for lung cancers: Where are we now?

Epidermal growth factor receptor (EGFR) kinase domain mutations (from exon 18 to 21) alter the efficacy of the EGFR tyrosine kinase inhibitors gefitinib (Iressa) and erlotinib (Tarceva). Lung cancer patients with drug-sensitive EGFR mutations initially respond, but acquire resistance after approximately one year of tyrosine kinase inhibitor treatment. This review summarizes EGFR gene mutation profiles for East Asian non-small-cell lung cancer patients according to recent publications. Strategies for the treatment of acquired resistance mediated by EGFR T790M are also reviewed.

Clinical and genetic features of lung squamous cell cancer in never-smokers

To evaluate the importance of specific driver mutations to the development and outcome of lung squamous cell cancer (SQCC) in never-smokers, we assessed the clinicopathological characteristics and outcomes of 597 patients who underwent complete resection of SQCCs. In total, 88 (14.7%) never-smokers and 509 (85.3%) ever-smokers were compared. The never-smokers included more females (42.05% vs. 1.57%, P < 0.001) and more often had a personal history of malignant disease (9.09% vs. 2.36%, P = 0.003). The tumors of never-smokers were more often poorly differentiated (70.45% vs. 53.24%, P = 0.010) and more often contained oncogenic mutations (21.05% vs 11.05%, P = 0.023), particularly EGFR mutations (13.16% vs 3.40%, P = 0.001). Never-smokers also tended to have poorer OS than smokers. Our results suggest lung SQCCs in never-smokers are a subtype distinct from SQCCs occurring in smokers.

Clinical profile of nonsmall cell lung carcinoma patients treated in a single unit at a tertiary cancer care center

BACKGROUND

Recent advances and understanding in the field of lung cancer and advent of newer treatments have shown a significant improvement in survival in the patients. The present study was conducted to analyze the clinical profile of nonsmall cell lung cancer (NSCLC) patients treated in a single unit at a tertiary cancer care center.

MATERIALS AND METHODS

In this retrospective analysis, 322 consecutive NSCLC patients from the year 2011 to 2012 treated in a single unit were included in the study. Patients with proven NSCLC were included in the study. The details of the patients included the demographic profile, pathological diagnosis as well as imaging data, tumor profile, details of treatment, and follow-up information.

RESULTS

The majority of the patients (95.6%) were in the age group >40 years. A large group of the patients (57.1%) were present/reformed smokers. The major histological type was adenocarcinoma (60.9%), of which 22.8% patients were found to be epidermal growth factor receptor positive. Anaplastic lymphoma kinase rearrangement positivity rate was 4.8%. Furthermore, 68% patients had Stage 4 disease. Upfront palliative chemotherapy (CT) was offered in 61.8% patients and pemetrexed with platinum compounds was the main CT regimen (46.6%). Partial response was achieved in 45.7% patients, whereas stable disease was observed in 10.9% cases. Median progression-free survival was 5 months and overall survival was 55% at 36 months.

CONCLUSION

NSCLC forms the largest subgroup of lung cancer with the patients presenting with advanced stages of disease. This area needs to be explored for the early detection and subsequently the radical treatment of the patients. Personalized approach may be considered for the management of lung cancer by identifying new predictive and prognostic biomarkers of this disease.

Characterization of distinct types of KRAS mutation and its impact on first-line platinum-based chemotherapy in Chinese patients with advanced non-small cell lung cancer

We performed this retrospective study to investigate whether the KRAS mutation status and its subtypes could predict the effect of first-line platinum-based chemotherapy in Chinese patients with non-small cell lung cancer (NSCLC). Patients received who had KRAS mutations were enrolled. Correlations between KRAS mutations, specific mutant subtypes and responses to chemotherapy were analyzed using Kaplan-Meier and Cox proportional hazard methods. A total of 2,183 cases who received KRAS mutation detection were included. A total of 218 of these cases were indicated to have KRAS mutations. KRAS mutations were identified more commonly in males compared with females (P=0.035). The most common subtypes were G12C, G12D and G12V. Among 73 KRAS mutant patients and 100 EGFR/ALK/KRAS wild-type patients with advanced NSCLC, KRAS-mutant NSCLC patients had a significantly shorter progression-free survival (P=0.007) compared with NSCLC patients with KRAS wild-type. In addition, there was a shorter but marginally statistically significant progression-free survival (PFS) in KRAS mutant patients with adenocarcinoma compared with those with non-adenocarcinoma (P=0.051). In the KRAS mutant group, patients with the KRAS G12V mutation had the poorest PFS compared with non-G12V mutant cases (P=0.045). In conclusion, KRAS mutation was a negative predictive factor of PFS in Chinese patients with advanced NSCLC who received first platinum-based chemotherapy. Patients with KRAS G12V mutations exhibited the poorest PFS compared with those with other KRAS mutant types.

The correlation between programmed death-ligand 1 expression and driver gene mutations in NSCLC

OBJECTIVES

This study aimed to evaluate the correlation between positive PD-L1 expression and driver gene mutations in NSCLC and to seek preliminary evidence in favor of the strategy of PD-L1 inhibitors plus targeted agents.

RESULTS

The overall analyses revealed that positive PD-L1 expression had a significant relationship with KRAS status (RR = 1.26; 95% CI, 1.06-1.50, P = 0.010), but no correlation with clinical characteristics (gender, smoking status, histological types), driver gene status (EGFR, ALK) and overall survival (OS): male versus female (RR = 1.16; 95% CI, 0.95-1.42; P = 0.15), never smoking versus former/current smoking (RR = 0.79; 95% CI, 0.56-1.11; P = 0.17), adenocarcinoma versus non-adenocarcinoma (RR = 0.94; 95% CI, 0.63-1.41; P = 0.77), EGFR mutation versus EGFR wild type (RR = 0.74; 95% CI, 0.52-1.06; P = 0.10), ALK positive versus ALK negative (RR = 1.02; 95% CI, 0.75-1.38; P = 0.91), OS of positive PD-L1 expression versus that of negative PD-L1 expression (HR = 1.31, 95% CI, 0.90-1.90; P = 0.15), respectively. Noteworthily, subgroup analyses exhibited that in Chinese cohort studies, positive PD-L1 expression was significantly correlated with OS (HR = 1.75, 95% CI, 1.36-2.24, P < 0.0001); and in the studies using PD-L1 monoclonal antibodies (McAbs), positive PD-L1 expression was significantly correlated with KRAS mutation (RR = 1.32, 95% CI, 1.06-1.65, P = 0.01) and EGFR mutation (RR = 0.51, 95% CI, 0.28-0.93, P = 0.03).

MATERIALS AND METHODS

After thoroughly searching PubMed, EMBASE and Cochrane Library databases, 11 relevant studies incorporating 3128 cases were identified. The pooled data were analyzed via Review manager 5.3 software.

CONCLUSIONS

PD-L1 inhibitors probably was a potential promising option to manage advanced NSCLC harboring KRAS mutation.

Exceptional durable response to everolimus in a patient with biphenotypic breast cancer harboring an STK11 variant

Metastatic triple-negative breast cancer comprises 12%–17% of breast cancers and carries a poor prognosis relative to other breast cancer subtypes. Treatment options in this disease are largely limited to systemic chemotherapy. A majority of clinical studies assessing efficacy of targeted therapeutics (e.g., the mammalian target of rapamycin [mTOR] inhibitor everolimus) in advanced breast cancer patients have not utilized predictive genomic biomarker-based selection and have reported only modest improvement in the clinical outcome relative to standard of care. However, recent reports have highlighted significant clinical responses of breast malignancies harboring alterations in genes involved in the phosphoinositide 3-kinase (PI3K)/AKT/mTOR signaling pathway to mTOR-inhibitor-involving regimens, underscoring the potential clinical benefit of treating subsets of breast cancer patients with molecularly matched targeted therapies. As the paradigm of cancer treatment shifts from chemotherapeutic regimens to more personalized approaches, the identification of additional reliable biomarkers is essential for identifying patients likely to derive maximum benefit from targeted therapies. Herein, we report a near-complete and ongoing 14-mo response to everolimus therapy of a heavily pretreated patient with biphenotypic, metastatic breast cancer. Genomic profiling of the metastatic triple-negative liver specimen identified a single reportable point mutation, STK11 F354L, that appears to have undergone loss of heterozygosity. No other alterations within the PI3K/mTOR pathway were observed. Published functional biochemical data on this variant are conflicting, and germline data, albeit with unclear zygosity status, are suggestive of a benign polymorphism role. Together with the preclinical data, this case suggests further investigation of this variant is warranted to better understand its role as a potential biomarker for mTOR inhibitor sensitivity in the appropriate clinical context.

LKB1/STK11 mutations in non-small cell lung cancer patients: Descriptive analysis and prognostic value

BACKGROUND

LKB1/STK11 (STK11) is among the most inactivated tumor-suppressor genes in non-small cell lung cancer (NSCLC). While evidence concerning the biologic role of STK11 is accumulating, its prognostic significance in advanced NSCLC has not been envisaged yet.

MATERIALS AND METHODS

This retrospective analysis included consecutive NSCLC patients with available STK11 information who underwent a platinum-based chemotherapy. STK11 mutational status was correlated to clinico-pathological and mutational features. Kaplan-Meier and Cox models were used for survival curves and multivariate analyses, respectively.

RESULTS

Among the 302 patients included, 267 (89%) were diagnosed with stage IIIB/IV NSCLC and 25 (8%) harbored a STK11 mutation (STK11mut). No statistical differences were observed between STK11 status and clinico-pathological variables. We detected a significant correlation between STK11 and KRAS status (p=0.008); among the 25 STK11mut patients, 13 (52%) harbored a concomitant KRAS mutation. Overall survival (OS) was shorter for STK11mut (median OS=10.4months) compared to wild-type patients (STK11wt; median OS=17.3months) in univariate analysis (p=0.085). STK11 status did not impact upon OS in multivariate analysis (p=0.45) and non-significant results were observed for progression-free survival. The co-occurrence of KRAS and STK11 mutations suggest a trend toward detrimental effect in OS (p=0.12).

CONCLUSIONS

In our cohort enriched for advanced NSCLC patients who received platinum-based chemotherapy, STK11 mutations were not specifically associated with clinico-pathological features and they did not impact upon survival. We confirm the positive correlation between STK11 and KRAS mutations. The co-occurrence of KRAS and STK11 mutations could label a more aggressive molecular subtype of NSCLC.

Racial and Ethnic Differences in the Epidemiology and Genomics of Lung Cancer

BACKGROUND

Lung cancer is the most common cancer in the world. In addition to the geographical and sex-specific differences in the incidence, mortality, and survival rates of lung cancer, growing evidence suggests that racial and ethnic differences exist.

METHODS

We reviewed published data related to racial and ethnic differences in lung cancer.

RESULTS

Current knowledge and substantive findings related to racial and ethnic differences in lung cancer were summarized, focusing on incidence, mortality, survival, cigarette smoking, prevention and early detection, and genomics. Systems-level and health care professional-related issues likely to contribute to specific racial and ethnic health disparities were also reviewed to provide possible suggestions for future strategies to reduce the disproportionate burden of lung cancer.

CONCLUSIONS

Although lung carcinogenesis is a multifactorial process driven by exogenous exposures, genetic variations, and an accumulation of somatic genetic events, it appears to have racial and ethnic differences that in turn impact the observed epidemiological differences in rates of incidence, mortality, and survival.

Racial disparity in metabolic regulation of cancer

Genetic mutations and metabolic reprogramming are two key hallmarks of cancer, required for proliferation, invasion, and metastasis of the disease. While genetic mutations, whether inherited or acquired, are critical for the initiation of tumor development, metabolic reprogramming is an effector mechanism imperative for adaptational transition during the progression of cancer. Recent findings in the literature emphasize the significance of molecular cross-talk between these two cellular processes in regulating signaling and differentiation of cancer cells. Genome-wide sequencing analyses of cancer genomes have highlighted the association of various genic mutations in predicting cancer risk and survival. Oncogenic mutational frequency is heterogeneously distributed among various cancer types in different populations, resulting in varying susceptibility to cancer risk. In this review, we explore and discuss the role of genetic mutations in metabolic enzymes and metabolic oncoregulators to stratify cancer risk in persons of different racial backgrounds.

The Utility of Thyroid Transcription Factor 1 (TTF-1), Napsin A, Excision Repair Cross-Complementing 1 (ERCC1), Anaplastic Lymphoma Kinase (ALK) and the Epidermal Growth Factor Receptor (EGFR) Expression in Small Biopsy in Prognosis of Patients with Lung Adenocarcinoma - A Retrograde Single-Center Study from Croatia

Background

The present study was carried out in order to evaluate our institutional experience with small biopsy in diagnosis and molecular testing of lung adenocarcinoma. Few specific and predictive markers have been evaluated and correlated with clinicopathologic characteristics and survival in patients with lung adenocarcinoma who received platinum-based chemotherapy. There have not been such reports from Croatia.

Material/Methods

A total of 142 cases of lung adenocarcinoma were retrospectively investigated in small biopsies for the immunohistochemical expression of TTF-1, napsin A, ERCC1, ALK, and the EGFR mutation by real-time polymerase chain reaction (rtPCR).

Results

TTF-1, napsin A, and ERCC1 expression was found in 81%, 78%, and 69% of patients, respectively, and the expressions were not significantly associated with subtype. Expression of ALK was found in 4% and EGFR mutation in 10% of patients. Exon 19 deletions were the most common. Longer survival was significantly associated with TTF-1 positivity (p=0.007) and napsin A positivity (p=0.026). Higher relative risk of death significantly correlated with positive expression of ERCC1 (p=0.041).

Conclusions

Positive TTF-1 and napsin A expressions in lung adenocarcinoma tissues were useful diagnostic and favorable prognostic parameters. Positive ERCC1 expression was identified as a negative prognostic marker in patients treated with platinum-based chemotherapy. The percentages of EGFR and ALK mutations corresponded to those in previously published reports for Caucasians.

An Analysis of EGFR Mutations among 1506 Cases of Non-Small Cell Lung Cancer Patients in Guangxi, China

An association between epidermal growth factor receptor (EGFR) and clinical characteristics of non-small cell lung cancer (NSCLC) was reported ten years ago. In addition, a different type of relationship was seen in different ethic races. However, the relationship between these factors is not well understood in the Guangxi province. Up to now, there are only very limited data on the association of TTF1/EGFR protein positivity and EGFR mutation status in NSCLC. This study aims to investigate the role of EGFR gene mutation status on the clinical characteristics and the relationship with TTF-1/EGFR protein positivity of patients with NSCLC in Guangxi, China. 1506 samples from different patients with NSCLC were detected by amplification refractory mutation system for 29 hotspot mutations. Analysis of the relationship between clinical characteristics and EGFR mutation status was performed by using the crosstabs Chi-square and SPSS 21.0 software. Of 1506 samples, 537 (35.7%) revealed tyrosine kinase inhibitor (TKI) sensitive EGFR mutations with 27 (1.8%) cases harboring TKI resistant EGFR mutations or union co-existing EGFR-TKIs sensitive mutations. EGFR-TKIs sensitive mutations were not significantly associated with age and TNM-M stage (P = 0.863; P = 0.572, respectively). However, they were significantly associated with p-stage, TNM-T stage and TNM-N stage (P = 0.011, P < 0.001, P = 0.036, respectively). Immunohistochemical studies revealed that TTF-1 and EGFR protein expression level were all associated with EGFR mutation status (P < 0.001, P = 0.002, respectively). Of the 537 EGFR-TKIs sensitive mutation cases, the rates of exon 19-del, 18 G719X point, exon 21 L858R and L861Q points were 54.6, 0.9, 42.3 and 0.9%, respectively. EGFR TKI-sensitive mutations commonly occur in female, non-smoking and adenocarcinoma patients. The p-stage, TNM-T stage, TNM-N stage, EGFR and TTF-1 protein expression levels have close relationships with EGFR mutation status.

Analysis of the frequency of EGFR, KRAS and ALK mutations in patients with lung adenocarcinoma in Croatia

Background

Many studies have been published on the mutational status of patients with lung adenocarcinomas, and great population-based variability in mutation frequencies has been reported. The main objective of the present study was to analyze the EGFR, KRAS and ALK mutation status in a representative cohort of patients in Croatia with lung adenocarcinomas and to correlate the mutational status with clinical data.

Methods

All patients who were newly diagnosed within 6 months with histologically proven primary lung adenocarcinomas were included. Mutational analyses for EGFR and KRAS mutations were performed in a cobas z 480 analyzer. ALK immunohistochemistry was performed using the D5F3 clone on Benchmark XT instrument. Clinical data were obtained from the medical records.

Results

Of the 324 patients, 59.9 % were male. At the time of diagnosis, the patients ranged in age range from 35 to 88 years (median 63 years). Most of the patients were current smokers or former smokers (77.2 %). EGFR mutations were found in 15.7 % of the patients, and of these mutations, exon 19 deletion was the most common (45.1 %). KRAS mutations were present in 34.9 % of the patients, while 4.1 % of patients were ALK-positive. The statistical significance of the presence of mutations was detected for both gender and smoking.

Conclusion

The detected mutation rates demonstrated a slightly higher prevalence of KRAS mutations, but not a higher prevalence of EGFR mutations or ALK gene rearrangement, in comparison with the rates found in other European countries. EGFR and ALK mutational status showed a statistically significant correlation with gender as well as with smoking, while KRAS mutation status showed a statistically significant correlation only with smoking.

Electronic supplementary material

The online version of this article (doi:10.1186/s13000-016-0544-9) contains supplementary material, which is available to authorized users.

Inactivation of the LKB1-AMPK signaling pathway does not contribute to salivary gland tumor development - a short report

PURPOSE

Activation of AMPK by the tumor suppressor LKB1 represents an essential gatekeeping step for cells under energetic stress to prevent their growth and proliferation by inhibiting mTOR activation, until the energy supply normalizes. The LKB1/AMPK pathway is frequently downregulated in various types of cancer, thereby uncoupling tumor cell growth and proliferation from energy supply. As yet, little information is available on the role of the LKB1/AMPK pathway in tumors derived from salivary gland tissues.

METHODS

We performed LKB1 protein expression and AMPK and mTOR activation analyses in several salivary gland tumor types and their respective healthy control tissues using immunohistochemistry.

RESULTS

No significant downregulation of LKB1 expression or decreased activation of AMPK or mTOR were observed in any of the salivary gland tumors tested. In contrast, we found that the salivary gland tumors exhibited an increased rather than a decreased AMPK activation. Although the PI3K/Akt pathway was found to be activated in most of the analyzed tumor samples, the unchanged robust activity of LKB1/AMPK likely prevents (over)activation of mTOR.

CONCLUSION

In contrast to many other types of cancer, inactivation or downregulation of the LKB1/AMPK pathway does not substantially contribute to the pathogenesis of salivary gland tumors.

KRAS-Mutant Lung Cancers in the Era of Targeted Therapy

KRAS-mutant lung cancers account for approximately 25% of non-small cell lung carcinomas, thus representing an enormous burden of cancer worldwide. KRAS mutations are clear drivers of tumor growth and are characterized by a complex biology involving the interaction between mutant KRAS, various growth factor pathways, and tumor suppressor genes. While KRAS mutations are classically associated with a significant smoking history, they are also identified in a substantial proportion of never-smokers. These mutations are found largely in lung adenocarcinomas with solid growth patterns and tumor-infiltrating lymphocytes. A variety of tools are available for diagnosis including Sanger sequencing, multiplex mutational hotspot profiling, and next-generation sequencing. The prognostic and predictive roles of KRAS status remain controversial. It has become increasingly clear, however, that KRAS mutations drive primary resistance to EGFR tyrosine kinase inhibition. Until recently, mutant KRAS was not thought of as a clinically-targetable driver in lung cancers. With the expansion of our knowledge regarding the biology of KRAS-mutant lung cancers and the role of MEK and PI3K/mTOR inhibition, the face of targeted therapeutics for this genomic subset of patients is slowly beginning to change.

PD-1/PD-L1 expression in non-small-cell lung cancer and its correlation with EGFR/KRAS mutations

This study was aimed to detect the correlation among EGFR/KRAS status and PD-1/PD-L1 expression in non-small-cell lung cancer (NSCLC) patients. PD-1 and PD-L1 expressions were detected by immunohistochemistry in 100 surgically resected lung adenocarcinoma tissues and were statistically correlated with clinicopathological characteristics including EGFR and KRAS statuses. Besides, the overall survival (OS) times were analyzed. There was a statistical significances between PD-1 expression in tumor and KRAS status (P = 0.043), with a higher mutation rate in with lower PD-1 expression patients. There was a statistical significance between PD-L1 expression in tumor and EGFR status (P = 0.012), with a higher mutation rate in patients with lower PD-L1 expression. The OS of patients with EGFR mutation was significantly longer than those without EGFR mutation. The OS of patients with lower PD-L1 in tumor was significantly longer than those with higher PD-L1 expression. We found negative associations between PD-L1 expression in tumor and mutated EGFR status, as well as between PD-1 expression in tumor and mutated KRAS status.

A Sensitive NanoString-Based Assay to Score STK11 (LKB1) Pathway Disruption in Lung Adenocarcinoma

INTRODUCTION

Serine/threonine kinase 11 gene (STK11), better known as liver kinase β1, is a tumor suppressor that is commonly mutated in lung adenocarcinoma (LUAD). Previous work has shown that mutational inactivation of the STK11 pathway may serve as a predictive biomarker for cancer treatments, including phenformin and cyclooxygenase-2 inhibition. Although immunohistochemical (IHC) staining and diagnostic sequencing are used to measure STK11 pathway disruption, there are serious limitations to these methods, thus emphasizing the importance of validating a clinically useful assay.

METHODS

An initial STK11 mutation mRNA signature was generated using cell line data and refined using three large, independent patient databases. The signature was validated as a classifier using The Cancer Genome Atlas (TCGA) LUAD cohort as well as a 442-patient LUAD cohort developed at Moffitt. Finally, the signature was adapted to a NanoString-based format and validated using RNA samples isolated from formalin-fixed, paraffin-embedded tissue blocks corresponding to a cohort of 150 patients with LUAD. For comparison, STK11 IHC staining was also performed.

RESULTS

The STK11 signature was found to correlate with null mutations identified by exon sequencing in multiple cohorts using both microarray and NanoString formats. Although there was a statistically significant correlation between reduced STK11 protein expression by IHC staining and mutation status, the NanoString-based assay showed superior overall performance, with a -0.1588 improvement in area under the curve in receiver-operator characteristic curve analysis (p < 0.012).

CONCLUSION

The described NanoString-based STK11 assay is a sensitive biomarker to study emerging therapeutic modalities in clinical trials.

Assessment and prognostic analysis of EGFR mutations or/and HER2 overexpression in Uygur's Non-small Cell Lung Cancer

AIM

The epidermal growth factor receptor (EGFR) mutations and human epidermal growth factor receptor HER-2/neu (HER2) have been established roles in the signal transduction pathways leading to cell growth and differentiation. The present study focus on the significance of EGFR mutations combined with HER2 overexpression on survival outcomes in Non-small Cell Lung Cancer patients in Uygur population.

METHODS

A total of 111 consecutive Uygurods: A total of 111 consecutive Cell Lung Cancer under went lung Cell Lung biopsy or surgery at the Affiliated Tumor Hospital of Xin Jiang Medical University between March 2009 and January 2013 were included in this retrospective study. All the patients included had received gefitinib 250 mg once daily. The HER2 expression were evaluated by immunohistochemical staining with score of membranous staining being 0 = none, 1 = weak, 2 = 10-30% cells, 3≥30% cells stained, and Real-time PCR techniques were conducted to detect mutations of EGFR through 21 kinds of human EGFR gene mutation detection kits. A retrospective review of the medical records was analyzed to determine the correlation between the presence of EGFR mutations combined with HER2 overexpression and clinicopathological factors.

RESULTS

The overall rate of EGFR mutation was 10.81% (n = 12), which mainly involved exons 19 (83.33%, n = 10), 21 (16.67%, n = 2). The overall rate of HER2 overexpression was 21.62% (n = 24). EGFR mutation combined with HER2 overexpression analysis was performed in 111 patients, with an overall rate of 5.41% (n = 6). Median progression-free survival and overall survival were significantly longer in the EGFR mutations group than in the wild type group (PFS: 10.0±1.5 versus 3.8±1.4 months, P = 0.000; OS: 27.3±2.9 versus 19.1±4.7 months, P = 0.000). The ORR in patients with HER2 overexpression was 29.17%, and 13.80% in those patients with HER2 negative, but no significant difference (P = 0.121). The median PFS and OS in HER2 positive group showed no significant difference compared with HER2 negative group (PFS: 4.7±1.2 months versus 3.9±1.6 months, P = 0.085; OS: 20.5±2.4 versus 19.2±2.6 months, P = 0.094). As regarding to ORR, PFS and OS, EGFR mutations combined with HER2 overexpression patients showed no superior efficacy to gefitinib treatment compared with EGFR mutations combined with HER2 negative.

CONCLUSION

In Uygur population, progression-free survivals were improved in Non-small Cell Lung Cancer with EGFR mutations. HER2 overexpression provided a poor prognostic factor in Non-small Cell Lung Cancer.

Transdifferentiation of lung adenocarcinoma in mice with Lkb1 deficiency to squamous cell carcinoma

Lineage transition in adenocarcinoma (ADC) and squamous cell carcinoma (SCC) of non-small cell lung cancer, as implicated by clinical observation of mixed ADC and SCC pathologies in adenosquamous cell carcinoma, remains a fundamental yet unsolved question. Here we provide in vivo evidence showing the transdifferentiation of lung cancer from ADC to SCC in mice: Lkb1-deficient lung ADC progressively transdifferentiates into SCC, via a pathologically mixed mAd-SCC intermediate. We find that reduction of lysyl oxidase (Lox) in Lkb1-deficient lung ADC decreases collagen disposition and triggers extracellular matrix remodelling and upregulates p63 expression, a SCC lineage survival oncogene. Pharmacological Lox inhibition promotes the transdifferentiation, whereas ectopic Lox expression significantly inhibits this process. Notably, ADC and SCC show differential responses to Lox inhibition. Collectively, our findings demonstrate the de novo transdifferentiation of lung ADC to SCC in mice and provide mechanistic insight that may have important implications for lung cancer treatment.

Predictive biomarkers in precision medicine and drug development against lung cancer

The molecular characterization of various cancers has shown that cancers with the same origins, histopathologic diagnoses, and clinical stages can be highly heterogeneous in their genetic and epigenetic alterations that cause tumorigenesis. A number of cancer driver genes with functional abnormalities that trigger malignant transformation and that are required for the survival of cancer cells have been identified. Therapeutic agents targeting some of these cancer drivers have been successfully developed, resulting in substantial improvements in clinical symptom amelioration and outcomes in a subset of cancer patients. However, because such therapeutic drugs often benefit only a limited number of patients, the successes of clinical development and applications rely on the ability to identify those patients who are sensitive to the targeted therapies. Thus, biomarkers that can predict treatment responses are critical for the success of precision therapy for cancer patients and of anticancer drug development. This review discusses the molecular heterogeneity of lung cancer pathogenesis; predictive biomarkers for precision medicine in lung cancer therapy with drugs targeting epidermal growth factor receptor (EGFR), anaplastic lymphoma kinase (ALK), c-ros oncogene 1 receptor tyrosine kinase (ROS1), and immune checkpoints; biomarkers associated with resistance to these therapeutics; and approaches to identify predictive biomarkers in anticancer drug development. The identification of predictive biomarkers during anticancer drug development is expected to greatly facilitate such development because it will increase the chance of success or reduce the attrition rate. Additionally, such identification will accelerate the drug approval process by providing effective patient stratification strategies in clinical trials to reduce the sample size required to demonstrate clinical benefits.

The mutation rates of EGFR in non-small cell lung cancer and KRAS in colorectal cancer of Chinese patients as detected by pyrosequencing using a novel dispensation order

BACKGROUND

The purpose of this study was to develop a cost-effective approach for the determination of EGFR and KRAS mutations in formalin-fixed paraffin-embedded (FFPE) non-small cell lung cancer (NSCLC) and colorectal cancer (CRC) samples from Chinese patients based on a sensitive pyrosequencing (PS) technique.

METHODS

The NSCLC and CRC cell lines were tested to determine the limitation of detection and reproducibility of the PS method. In addition, 494 NSCLC and 1099 CRC patient samples were assayed by PS to evaluate the EGFR or KRAS mutation patterns according to the clinicopathological features.

RESULTS

The PS assay was able to reproducibly detect as few as 2 % mutant alleles with excellent linearity. EGFR mutations were detected in 35.63 % of the NSCLC samples, and KRAS mutations were detected in 39.76 % of the CRC samples. EGFR mutations were more frequently observed to be significant by multivariate analysis in NSCLC patients who were 65 years old or younger (OR = 2.51), had a nonsmoking history (OR = 3.63), and adenocarcinoma (OR = 3.57), but not in females (OR = 0.64). KRAS mutations were more frequently detected in CRC patients who were female (OR = 1.64) and 50 years old or older (OR = 4.17), and had adenocarcinoma (OR = 2.41).

CONCLUSIONS

This is the first extensive validation of PS on FFPE samples using the detection of EGFR exons 18-21 mutations and KRAS exon 2 mutations. Our results demonstrate the utility of PS analysis for the detection of somatic EGFR and KRAS mutations in clinical samples and provide important clinical and molecular characteristics of NSCLC and CRC from Chinese patients.