Mutations within the tyrosine kinase domain of EGFR gene specifically occur in lung adenocarcinoma patients with a low exposure of tobacco smoking

The Impact of Mutational Hotspots on Cancer Survival

BACKGROUND

Cofactors, biomarkers, and the mutational status of genes such as TP53, EGFR, IDH1/2, or PIK3CA have been used for patient stratification. However, many genes exhibit recurrent mutational positions known as hotspots, specifically linked to varying degrees of survival outcomes. Nevertheless, few hotspots have been analyzed (e.g., TP53 and EGFR). Thus, many other genes and hotspots remain unexplored.

METHODS

We systematically screened over 1400 hotspots across 33 TCGA cancer types. We compared the patients carrying a hotspot against (i) all cases, (ii) gene-mutated cases, (iii) other mutated hotspots, or (iv) specific hotspots. Due to the limited number of samples in hotspots and the inherent group imbalance, besides Cox models and the log-rank test, we employed VALORATE to estimate their association with survival precisely.

RESULTS

We screened 1469 hotspots in 6451 comparisons, where 314 were associated with survival. Many are discussed and linked to the current literature. Our findings demonstrate associations between known hotspots and survival while also revealing more potential hotspots. To enhance accessibility and promote further investigation, all the Kaplan-Meier curves, the log-rank tests, Cox statistics, and VALORATE-estimated null distributions are accessible on our website.

CONCLUSIONS

Our analysis revealed both known and putatively novel hotspots associated with survival, which can be used as biomarkers. Our web resource is a valuable tool for cancer research.

Generation of novel complete HLA class I monoallelic cell lines used in an MHC stabilization assay for neoantigen evaluation

Immunogenic neoantigens derived from somatic mutations in cancer have been identified through clinical studies with the cloning of tumor-infiltrating T cells, and cancer driver gene mutation-derived epitopes have been reported; however, these are rare. At present, the validation of epitopes predicted in silico is difficult as human T-cell clonal diversity cannot be reproduced in vitro or in experimental animal models. To confirm the epitope peptides presented by human leukocyte antigen (HLA) class I molecules predicted in silico, biochemical methods such as major histocompatibility complex (MHC) stabilization assays and mass spectrometry-mediated identification have been developed based on HLA-A*02:01 monoallelic T2 cells and HLA-C*01:02 monoallelic LCL721.221 cells. Therefore, in the present study, to prevent confusion due to peptide cross-presentation among HLA molecules, HLA class I monoallelic B-cell clones were generated from the TISI cell line by knocking out HLA-ABC and TAP2, and knocking in HLA alleles. To explore cancer driver mutations as potential targets for immunotherapy, exome sequencing data from 5,143 patients with cancer enrolled in a comprehensive genome analysis project at the Shizuoka Cancer Center were used to identify somatic amino acid substituted mutations and the 50 most frequent mutations in five genes, TP53, EGFR, PIK3CA, KRAS and BRAF, were identified. Using NetMHC4.1, the present study predicted whether epitopes derived from these mutations are presented on major HLA-ABC alleles in Japanese individuals and synthesized 138 peptides for MHC stabilization assays. The authors also attempted to examine the candidate epitopes at physiological temperatures by using antibody clone G46-2.6, which can detect HLA-ABC, independent of β2-microglobulin association. In the assays, although the peptide-induced HLA expression levels were associated with the predicted affinities, the respective HLA alleles exhibited varying degrees of responsiveness, and unexpectedly, p53-mutant epitopes with predicted weak affinities exhibited strong responses. These results suggested that MHC stabilization assays using completely monoallelic HLA-expressing B-cell lines are useful for evaluating the presentation of neoantigen epitopes.

The relation between epidermal growth factor receptor mutations profiles and smoking patterns in patients with lung adenocarcinoma: A cross-sectional study

Background

Non-small cell lung cancer (NSCLC) accounts for 85% of lung cancer cases, with smoking being a critical risk factor. The identification of NSCLC patients harboring epidermal growth factor receptor (EGFR) mutations, sensitized to tyrosine kinase inhibitors, has revolutionized treatment plans, resulting in improved clinical responses and reduced chemotherapy toxicity. This study aimed to assess the relationship between EGFR mutations and smoking patterns in patients diagnosed with lung adenocarcinoma referred to major pathologic laboratories.

Methods

This cross-sectional study included 217 NSCLC patients aged above 18 years. Molecular abnormalities of the EGFR gene were analyzed by polymerase chain reaction amplification of exons 18-21 accompanied by Sanger sequencing. Then, the data were analyzed using the SPSS 26 software. Logistic regression analysis, χ ² test, and Mann-Whitney U test were used to evaluate the relation between EGFR mutations and smoking patterns.

Results

EGFR mutations were identified in 25.3% of patients, predominantly involving deletion in exon 19 (61.8%). For most of the mutant EGFR patients, the majority were nonsmokers (81.8%), and 52.7% were female patients. Besides, the median duration of smoking was 26 years and the median frequency of smoking was 23 pack-years in the mutant EGFR group, both of which were lower compared to the wild mutant group. Moreover, female gender, current, and heavy smoking were significantly correlated with EGFR mutations based on the univariate logistic regression analysis (p: 0.004, 0.005, and 0.001, respectively).

Conclusions

Female gender and nonsmoker status were strongly associated with positive EGFR mutations. While guidelines traditionally recommended EGFR testing primarily for female nonsmokers with advanced NSCLC, our study in line with the recently published evidence has shown a significant prevalence of positive EGFR mutations among male patients and smokers. Therefore, routine mutation testing is suggested for all NSCLC patients. Considering the limited access to EGFR testing laboratories in developing countries, the results of such epidemiological surveys can assist oncologists in choosing the most suitable treatment plan.

Prognostic impact of circulating tumor cells detected with the microfluidic "Universal CTC-chip" for primary lung cancer

Detecting rare circulating tumor cells (CTCs) in the bloodstream is extremely challenging. We had previously developed a novel polymeric microfluidic device, "CTC-chip," for capturing CTCs and have shown high capture efficiency in lung cancer cell lines by conjugating antibodies against epithelial cell adhesion molecules (EpCAM). This study aimed to optimize the EpCAM-chip and clarify the prognostic impact of CTCs in lung cancer patients. Of the 123 patients with pathologically proven lung cancer, both progression-free survival (p = 0.037) and cancer-specific survival (p = 0.0041) were predominantly poor when CTCs were detected before treatment. After classification into surgical and chemotherapy groups, progression-free survival was worse in CTC-positive patients in both groups (surgery, p = 0.115; chemotherapy, p = 0.012), indicating that the detection of baseline CTCs is a risk factor for recurrence and progression. Furthermore, we demonstrated that captured CTCs can be recovered using micromanipulators and performed mutation analysis using PCR. Thus, the EpCAM-chip is a highly sensitive system for detecting CTCs that contributes to the prediction of recurrence and progression and enables genetic analysis of captured CTCs, which may open new diagnostic, therapeutic, and prognostic options for lung cancer patients.

Metachronous Isolated Contralateral Lung Metastasis from Pulmonary Adenosquamous Carcinoma with EGFR Mutation

Lung metastasis and metachronous double primary lung cancer are both common and often present diagnostic challenges. We present a case of metachronous isolated contralateral lung metastasis from pulmonary adenosquamous carcinoma with EGFR mutation. A 75-yearold woman presented with left lung nodule on a routine follow-up chest radiograph. She had had surgery for pulmonary adenocarcinoma with EGFR Ex21 L858R mutation 6 years ago. She underwent surgical resection, and histologic findings revealed adenosquamous carcinoma with the same EGFR mutation. Re-assessment of the resected specimen of the primary tumor resected 6 years ago revealed the morphologically similarity to the left lung tumor. Based on morphological and genetic identity, final diagnosis was adenosquamous cell carcinoma and metachronous isolated contralateral lung metastasis. The diagnosis of metachronous isolated metastasis is difficult but important for appropriate management and prediction of prognosis. A careful pathological examination and evaluation of genetic abnormality are needed to make the correct diagnosis.

[Clinical Features of EGFR Mutation Negative in Patients with Non-small Cell Lung Cancer and Brain Metastases]

除少见的间变性淋巴瘤激酶（anaplastic lymphoma kinase, ALK）及原癌基因-1受体酪氨酸激酶（c-ros oncogene 1-receptor tyrosine kinase, ROS1）阳性敏感融合外，非表皮生长因子受体（epidermal growth factor receptor, EGFR）敏感突变的非小细胞肺癌（non-small cell lung cancer, NSCLC）脑转移患者目前无有效的全身治疗药物，整体预后较差。由于传统药物血脑屏障透过率低，脑转移的局部治疗尤其是放疗具有非常重要作用。为了更好地认识EGFR突变阴性NSCLC脑实质转移的特点，本文从脑转移的发病率、发病时间、发病部位、病灶数目及大小、发病症状、治疗疗效和病情演变等方面综述了EGFR突变阴性NSCLC脑实质转移的临床特征以及治疗，为脑实质转移局部治疗的介入时机以及局部治疗技术选择提供参考。

Molecular Mechanisms and Targeted Therapies Including Immunotherapy for Non-Small Cell Lung Cancer

Lung cancer is the leading cause of cancer death worldwide. Molecular targeted therapy has greatly advanced the field of treatment for non-small cell lung cancer (NSCLC), which accounts for the majority of lung cancers. Indeed, gefitinib, which was the first molecular targeted therapeutic agent, has actually doubled the survival time of NSCLC patients. Vigorous efforts of clinicians and researchers have revealed that lung cancer develops through the activating mutations of many driver genes including the epidermal growth factor receptor (EGFR), anaplastic lymphoma kinase (ALK), c-ros oncogene 1 (ROS1), v-Raf murine sarcoma viral oncogene homolog B (BRAF), and rearranged during transfection (RET) genes. Although ALK, ROS1, and RET are rare genetic abnormalities, corresponding tyrosine kinase inhibitors (TKIs) can exert dramatic therapeutic effects. In addition to anticancer drugs targeting driver genes, bevacizumab specifically binds to human vascular endothelial growth factor (VEGF) and blocks the VEGF signaling pathway. The VEGF signal blockade suppresses angiogenesis in tumor tissues and inhibits tumor growth. In this review, we also explore immunotherapy, which is a promising new NSCLC treatment approach. In general, antitumor immune responses are suppressed in cancer patients, and cancer cells escape from the immune surveillance mechanism. Immune checkpoint inhibitors (ICIs) are antibodies that target the primary escape mechanisms, immune checkpoints. Patients who respond to ICIs are reported to experience longlasting therapeutic effects. A wide range of clinical approaches, including combination therapy involving chemotherapy or radiation plus adjuvant therapy, are being developed.

Pet ownership and the risk of dying from lung cancer, findings from an 18 year follow-up of a US national cohort

PURPOSE

In contrast to the popularity of pets, research on the health effects of living with pets, particularly, on the risk of cancer, is minimal and inconclusive. We longitudinally examined relationships between pet ownership and the risk of dying from lung cancer.

METHODS

We analyzed nationally representative data of 13,725 adults aged ≥ 19 who answered the question about pet ownership in the Third National Health and Nutrition Examination Survey, 1988-1994, as the baseline survey. Vital status was followed through December 31st, 2010.

RESULTS

About 43% of the study population owned pets, with 20.4% having cats and 4.6% having birds. A total of 213 lung cancer deaths were recorded by the end of 183,094 unweighted person-years of follow-up with a lung-cancer specific death rate of 1.00 per 1000 person-years. After adjustment for cigarette smoking, alcohol drinking, physical activity, body mass index, history of atopic conditions, and serum cotinine, owning a pet (any) was associated with a doubled mortality rate among women for lung cancer [hazard ratio (HR)= 2.31 (1.41-3.79)] over non-owners. This association was largely attributed to having a cat or a bird. The HR was 2.85 (1.62-5.01) for cats, and 2.67 (0.68-10.5) for birds. The HR for dogs was 1.01 (0.57-1.77). No significant patterns of association were observed among men either for any pets or for a subtype of pet.

CONCLUSIONS

Living with a pet, especially, a cat or a bird, was significantly associated with elevated hazard of dying from lung cancer among women. The detrimental effect that pets conferred was not explained by confounding from cigarette smoking or atopic conditions.

Genetic and epigenetic alterations of the EGFR and mutually independent association with BRCA1, MGMT, and RASSF1A methylations in Vietnamese lung adenocarcinomas

Genetic and epigenetic alterations importantly contribute to the pathogenesis of lung cancer. In the study, we measured the frequency and distribution of molecular abnormalities of EGFR as well as the aberrant promoter methylations of BRCA1, MGMT, MLH1, and RASSF1A in Vietnamese lung adenocarcinomas. We investigated the association between genetic and epigenetic alteration, and between each abnormality with clinicopathologic parameters. Somatic EGFR mutation that was found in 49/139 (35.3%) lung adenocarcinomas showed a significant association with young age, female gender, and non-smokers. EGFR overexpression was identified in 82 tumors (59.0%) and statistical relationships with EGFR or BRCA1 methylation but not EGFR mutation. In addition, EGFR, BRCA1, MGMT, MLH1, and RASSF1A methylations were found in 33 (23.7%), 41 (29.5%), 46 (33.1%), 28 (20.1%), and 41 (29.5%) cases of a total of 139 lung adenocarcinomas, respectively. The RASSF1A methylation was found to be linked to the smoking habit. Methylations in MGMT and RASSF1A were also found to correlate with metastasis status. Furthermore, the distribution of EGFR mutation and that of BRCA1, MGMT or RASSF1A methylation were significantly exclusive in lung adenocarcinomas. The main finding of our study demonstrate that epigenetic abnormalities might play a critical role for the lung tumorigenesis in patients with smoking history and metastasis, and partly affect the predictive value of EGFR mutations through blocking expression due to promoter EGFR hypermethylation. Mutually exclusive distribution of genetic and epigenetic alterations reflects differently biological characteristics in the etiology of lung adenocarcinomas.

Erlotinib treatment after platinum-based therapy in elderly patients with non-small-cell lung cancer in routine clinical practice - results from the ElderTac study

Background

In this prospective non-interventional study, the effectiveness and tolerability of erlotinib in elderly patients with non-small-cell lung cancer (NSCLC) after ≥1 platinum-based chemotherapy were assessed.

Methods

A total of 385 patients ≥65 years of age with advanced NSCLC receiving erlotinib were observed over 12 months. The primary endpoint was the 1-year overall survival (OS) rate.

Results

Patients were predominantly Caucasian (99.2%), a mean of 73 years old; 24.7% had an Eastern Cooperative Oncology Group performance status (ECOG PS) ≥2. Most common tumor histologies were adenocarcinoma (64.9%) and squamous cell carcinoma (22.3%). Of 119 patients tested, 15.1% had an activating epidermal growth factor receptor gene (EGFR) mutation. The 1-year OS rate was 31% (95% CI 25–36) with a median OS of 7.1 months (95% CI 6.0–7.9). OS was significantly better in females than males (p = 0.0258) and in patients with an EGFR mutation compared to EGFR wild-type patients (p = 0.0004). OS was not affected by age (p = 0.3436) and ECOG PS (p = 0.5364). Patients with squamous NSCLC tended to live longer than patients with non-squamous EGFR wild-type tumors (median OS: 8.6 vs 5.5 months). Cough and dyspnea improved during the observation period. The erlotinib safety profile was comparable to that in previous studies with rash (45.2%) and diarrhea (22.6%) being the most frequently reported adverse events.

Conclusions

Erlotinib represents a suitable palliative treatment option in further therapy lines for elderly patients with advanced NSCLC. The results obtained under real-life conditions add to our understanding of the benefits and risks of erlotinib in routine clinical practice.

Trial registration

BfArM (https://www.bfarm.de; ML23023); ClinicalTrials.gov (NCT01535729; 20 Feb 2012).

Epidermal Growth Factor Receptor Mutation as a Risk Factor for Recurrence in Lung Adenocarcinoma

BACKGROUND

The presence of epidermal growth factor receptor (EGFR) mutations is an established prognostic factor for patients with advanced lung adenocarcinoma. Here, we examined whether EGFR mutation status is a prognostic factor for patients who had undergone surgery.

METHODS

Clinicopathologic data from 1,463 patients who underwent complete surgical resection for lung adenocarcinoma between 2005 and 2012 were collected. Differences in postoperative recurrence-free survival and overall survival according to EGFR mutation status were evaluated.

RESULTS

Of 835 eligible patients, the numbers of patients with wild-type EGFR (WT), exon 19 deletion (Ex19), and exon 21 L858R (Ex21) were 426, 175, and 234, respectively. Patients with Ex19 had a significantly higher incidence of extrathoracic recurrence than patients with Ex21 (p = 0.004). The 5-year recurrence-free survival rates for patients with WT, Ex19, and Ex21 were 63.0%, 67.5%, and 78.2%, respectively. The Ex21 group had a significantly longer recurrence-free survival than the WT group (p < 0.001) and the Ex19 group (p = 0.016). The 5-year overall survival for patients with WT, Ex19, and Ex21 were 76.9%, 86.5%, and 87.5%, respectively. Patients with Ex19 and Ex21 had a significantly longer overall survival than patients with WT (Ex19, p = 0.009; Ex21, p < 0.001). Multivariate analysis for recurrence-free survival showed that Ex19 was significantly associated with a worse prognosis than Ex21 (p = 0.019).

CONCLUSIONS

Patients with Ex19 had significantly shorter recurrence-free survival and had extrathoracic recurrence more frequently than patients with Ex21 among patients with resected lung adenocarcinoma, implying that Ex19 could be a worse prognostic factor.

Marked response to nab-paclitaxel in EGFR mutated lung neuroendocrine carcinoma: A case report

RATIONALE

Lung cancer is the leading cause of cancer-related death in the world. Tyrosine kinase inhibitors (TKIs), which target mutated epidermal growth factor receptor (EGFR), have been the first-line treatment of late-stage lung adenocarcinoma harboring EGFR mutation. EGFR mutations are mostly identified in lung adenocarcinoma. However, it is rarely seen in lung neuroendocrine carcinoma, and treatment strategies remain under reported.

PATIENT CONCERNS

Here, we describe a 54-year-old Chinese man diagnosed with lung adenocarcinoma (cT4N3M1b, stage IV) with neuroendocrine differentiation and L858R mutation on exon 21. He developed progressive disease in liver 4 months later, and the biopsy of liver metastases showed neuroendocrine carcinoma maintained the same EGFR mutation.

DIAGNOSES

Lung adenocarcinoma and neuroendocrine carcinoma were identified by biopsy.

INTERVENTIONS

After a combined treatment with nab-paclitaxel and erlotinib, the patient achieved partial remission.

OUTCOMES

The patient's overall survival was 27 months.

LESSONS

This case highlights that EGFR mutated lung neuroendocrine carcinoma is not responsive to single-agent EGFR-TKI. However, combined application with nab-paclitaxel can improve its efficacy and prolong the patient's survival.

Evidence, Mechanism, and Clinical Relevance of the Transdifferentiation from Lung Adenocarcinoma to Squamous Cell Carcinoma

Lung adenocarcinoma (ADC) and squamous cell carcinoma (SCC) are two distinct subtypes of non-small-cell lung carcinoma. Interestingly, approximately 4% to 9% of human non-small-cell lung carcinoma tumors contain mixed adenomatous and squamous pathologies in a single lesion, clinically termed adenosquamous cell carcinoma. More important, these two different pathological components frequently share identical oncogenic mutations, indicative of a potential transition. Indeed, recent data have provided convincing evidence in supporting the ADC to SCC transdifferentiation in lungs. In the liver kinase B1 (official name STK11)-deficient mouse model, lung ADC can progressively transdifferentiate to SCC through pathologically mixed adenosquamous cell carcinoma as the intermediate status. Mechanistic studies further identify essential roles of extracellular matrix remodeling and metabolic reprogramming during this phenotypic transition. Small molecular compounds, including lysyl oxidase inhibitors and reactive oxygen species-inducing reagents such as phenformin, significantly accelerate the transition from lung ADC to SCC and thus confer lung tumors with drug resistance. Consistent with these findings, recent clinical studies have shown that epidermal growth factor receptor-mutant lung ADC can transdifferentiate to SCC in relapsed cancer patients. Together, these data support that this phenotypic transition from lung ADC to SCC might represent a novel mechanism for drug resistance. This review will summarize our current understanding of the transdifferentiation from lung ADC to SCC.

Impact of country of birth on genetic testing of metastatic lung adenocarcinomas in France: African women exhibit a mutational spectrum more similar to Asians than to Caucasians

Background

Limited data are available on the prevalence of oncogenic driver mutations in Caucasian populations, and especially in Europeans.

Aim

To evaluate the targetable mutational spectra in unselected patients with lung adenocarcinoma in routine clinical practice from several French hospitals, using the same molecular platform.

Patients and Methods

Samples from 2,219 consecutive patients with histologically-proven advanced lung adenocarcinoma were centrally analysed at a referenced and certified diagnostic platform in order to test for activating and resistance mutations in EGFR, KRAS, BRAF, ERBB2 and PI3KCA. Demographic and clinical features were retrieved from the medical charts. Multivariate binary logistic regression was used to determine the independent predictive factors for the occurrence of specific mutations, in the whole study population or in selected subgroups.

Findings

The overall respective incidence of EGFR, KRAS, BRAF, ERBB2 and PI3KCA mutations was 10.5%, 0.9%, 25%, 1.5%, 2.1% and 1.4%, in our study sample including 87.4% white Caucasians, 10.8% Africans and 1.8% Asians; 60.6% men, 30.7% never smoker (median age: 68.3 years). Ethnicity was an independent predictor for EGFR, KRAS and ERBB2 gene abnormalities. In all cases, a significantly higher prevalence of targetable EGFR and ERBB2, and a lower prevalence of resistance KRAS mutations were observed in African women as compared to African men or Caucasians.

Conclusions

In real life conditions of routine genetic testing, we have identified subsets of patients with specific targetable activating somatic mutations according to ethnicity, who could preferentially benefit from anti-EGFR and anti-ERBB2 targeted therapies.

Comparison of clinical outcomes of patients with non-small-cell lung cancer harbouring epidermal growth factor receptor exon 19 or exon 21 mutations after tyrosine kinase inhibitors treatment: a meta-analysis

PURPOSE

Exon 19 deletion and exon 21 L858R mutation were the most common epidermal growth factor receptor (EGFR) mutations. We examined the clinical impact of these two mutations in patients with non-small-cell lung cancer (NSCLC) after EGFR tyrosine kinase inhibitor (TKI) treatment.

METHODS

The outcomes of interest were progression-free survival (PFS), overall survival (OS) and objective response rates (ORR), network meta-analysis and direct meta-analysis were conducted to calculate the efficacy of EGFR-TKIs between these two mutations. We also investigated the association between EGFR mutation types and clinical characteristics.

RESULTS

A total of 4835 patients from 26 trials were assessed. EGFR-TKIs, compared with chemotherapy, significantly prolonged PFS and OS in both exon 19 deletion and exon 21 L858R mutation based on 8 trials. Network meta-analysis revealed that treatment with EGFR-TKIs had greater benefit in exon 19 deletion than in exon 21 L858R mutation. Furthermore, direct meta-analysis from 12 studies showed the similar result; patients with exon 19 deletion had a significantly longer PFS compared with exon 21 L858R mutation (HR, 0.69; 95 % CI, 0.57–0.82; P < 0.001). There were also greater benefit on OS (HR, 0.61; 95 % CI, 0.43–0.86; P = 0.005) and higher ORR (OR, 2.14; 95 % CI, 1.63–2.81; P < 0.001). Additionally, we found that a significant association between the type of mutation and age (P < 0.001) or smoking status (P = 0.022), but no other significant differences were detected in sex, histologic subtype and performance status between these two mutations.

CONCLUSIONS

Patients with NSCLC and EGFR exon 19 deletion had a longer PFS, OS and higher response rates after EGFR-TKI therapy compared with exon 21 L858R mutation.

Relationship of smoking status to genomic profile, chemotherapy response and clinical outcome in patients with advanced urothelial carcinoma

Smoking has been linked to urothelial carcinoma (UC), but the implications on genomic profile and therapeutic response are poorly understood. To determine how smoking history impacts genomic profile and chemotherapy response, clinicopathologic data was collected for patients with metastatic UC (mUC) across 3 academic medical centers and comprehensive genomic profiling (CGP) was performed through a CLIA-certified lab. Unsupervised hierarchical clustering based on smoking status was used to categorize the frequency of genomic alterations (GAs) amongst current smokers (CS), ex-smokers (ES) and non-smokers (NS), and survival was compared in these subsets. Fisher's exact test identified significant associations between GAs and smoking status. Amongst 83 patients, 23%, 55% and 22% were CS, ES, and NS, respectively, and 95% of patients had stage IV disease. With a median follow up of 14.4 months, the median overall survival (OS) was significantly higher in NS and ES (combined) as compared to CS (51.6 vs 15.6 months; P = 0.04). Of 315 cancer-related genes and 31 genes often related to rearrangement tested, heatmaps show some variations amongst the subsets. GAs in NSD1 were more frequent in CS as compared to other groups (P < 0.001). CS status negatively impacts OS in patients with mUC and is associated with genomic alterations that could have therapeutic implications.

Impact of Specific Epidermal Growth Factor Receptor (EGFR) Mutations and Clinical Characteristics on Outcomes After Treatment With EGFR Tyrosine Kinase Inhibitors Versus Chemotherapy in EGFR-Mutant Lung Cancer: A Meta-Analysis

Purpose

We examined the impact of different epidermal growth factor receptor (EGFR) mutations and clinical characteristics on progression-free survival (PFS) in patients with advanced EGFR-mutated non–small-cell lung cancer treated with EGFR tyrosine kinase inhibitors (TKIs) as first-line therapy.

Patients and Methods

This meta-analysis included randomized trials comparing EGFR TKIs with chemotherapy. We calculated hazard ratios (HRs) and 95% CIs for PFS for the trial population and prespecified subgroups and calculated pooled estimates of treatment efficacy using the fixed-effects inverse-variance-weighted method. All statistical tests were two sided.

Results

In seven eligible trials (1,649 patients), EGFR TKIs, compared with chemotherapy, significantly prolonged PFS overall (HR, 0.37; 95% CI, 0.32 to 0.42) and in all subgroups. For tumors with exon 19 deletions, the benefit was 50% greater (HR, 0.24; 95% CI, 0.20 to 0.29) than for tumors with exon 21 L858R substitution (HR, 0.48; 95% CI, 0.39 to 0.58; Pinteraction < .001). Never-smokers had a 36% greater benefit (HR, 0.32; 95% CI, 0.27 to 0.37) than current or former smokers (HR, 0.50; 95% CI, 0.40 to 0.63; Pinteraction < .001). Women had a 27% greater benefit (HR, 0.33; 95% CI, 0.28 to 0.38) than men (HR, 0.45; 95% CI, 0.36 to 0.55; treatment-sex interaction P = .02). Performance status, age, ethnicity, and tumor histology did not significantly predict additional benefit from EGFR TKIs.

Conclusion

Although EGFR TKIs significantly prolonged PFS overall and in all subgroups, compared with chemotherapy, greater benefits were observed in those with exon 19 deletions, never-smokers, and women. These findings should enhance drug development and economic analyses, as well as the design and interpretation of clinical trials.

Clinical analysis of 50 Eastern Asian patients with primary pulmonary large-cell neuroendocrine carcinoma

BACKGROUND

To understand the clinicopathological features of patients with primary pulmonary large-cell neuroendocrine carcinoma (LCNEC), including the frequency of epidermal growth factor receptor (EGFR) mutation, and to explore prognostic factors.

METHODS

We investigated a cohort of 50 individuals from our center database who were diagnosed with operable pulmonary LCNEC and treated in Sun Yat-sen University Cancer Center. Serum albumin (ALB) and neuron-specific enolase (NSE) were also collected. Survival curves were obtained with the Kaplan-Meier method, and the differences between groups in survival were tested by the log-rank test.

RESULTS

The median age was 59 years (range, 40-80 years). Fourteen patients underwent mutational analysis of EGFR; of these, 12 had wild-type EGFR and the remaining two had EGFR mutations in exons. The median disease-free survival (DFS) of pulmonary LCNEC was 49.3 months and that of overall survival (OS) was not reached. DFS and OS were shorter for patients with decreased serum ALB than for patients with normal serum ALB (P=0.003 and P=0.004, respectively). Meanwhile, a high level of NSE was also significantly associated with short DFS and OS (P=0.005 and P=0.000, respectively). Multivariate analysis showed that decrease in serum ALB was an independent prognostic factor for OS (P=0.046).

CONCLUSION

The frequency of EGFR mutation in LCNEC patients is low. Serum ALB and NSE levels are valuable prognostic factors for LCNEC patients.

The correlation of the International Association for the Study of Lung Cancer (IASLC)/American Thoracic Society (ATS)/European Respiratory Society (ERS) classification with prognosis and EGFR mutation in lung adenocarcinoma

BACKGROUND

The purpose of this study was to validate the prognostic effect and the frequency of mutations in the gene expressing epidermal growth factor receptor (EGFR) in lung adenocarcinoma of Japanese patients, on the basis of the new adenocarcinoma classification proposed by the International Association for the Study of Lung Cancer, American Thoracic Society, and European Respiratory Society.

METHODS

The new classification was used to reclassify 486 adenocarcinomas. The percentage of each histopathologic subtype and the predominant pattern were determined. EGFR mutation was also investigated. The relationship between these results and clinicopathologic backgrounds was investigated statistically.

RESULTS

No patients with adenocarcinoma in situ or minimally invasive adenocarcinoma died within the follow-up periods, followed by patients with lepidic predominant. Patients with papillary or acinar predominant, or invasive mucinous adenocarcinoma, showed almost similar overall survival (OS). The patients with solid predominant and micropapillary predominant showed the worst OS. Multivariate analysis showed that the new classification was an independent predictor of OS. The frequency of EGFR mutation was adenocarcinoma in situ (62%), minimally invasive adenocarcinoma (60%), lepidic (77%), acinar (49%), papillary (50%), solid (28%), micropapillary (43%), and invasive mucinous adenocarcinoma (0%).

CONCLUSIONS

This new adenocarcinoma classification is a very useful predictive marker to plan and determine a therapeutic strategy for lung adenocarcinoma.

Imaging Characteristics in ALK Fusion-Positive Lung Adenocarcinomas by Using HRCT

OBJECTIVES

We aimed to identify high-resolution computed tomography (HRCT) features useful to distinguish the anaplastic lymphoma kinase gene (ALK) fusion-positive and negative lung adenocarcinomas.

METHODS

We included 236 surgically resected adenocarcinoma lesions, which included 27 consecutive ALK fusion-positive (AP) lesions, 115 epidermal growth factor receptor mutation-positive lesions, and 94 double-negative lesions. HRCT parameters including size, air bronchograms, pleural indentation, spiculation, and tumor disappearance rate (TDR) were compared. In addition, prevalence of small lesions (≤20 mm) and solid lesions (TDR ≤20%) were compared.

RESULTS

AP lesions were significantly smaller and had lower TDR (%) than ALK fusion-negative (AN) lesions (tumor diameter: 20.7 mm ± 14.1 mm vs. 27.4 mm ± 13.8 mm, respectively, p <0.01; TDR: 22.8% ± 24.8% vs. 44.8% ± 33.2%, respectively, p <0.01). All AP lesions >20 mm (n = 7, 25.9%) showed a solid pattern. Among all small lesions, AP lesions had lower TDR and more frequent spiculation than AN lesions (p <0.01). Among solid lesions, AP lesions were smaller than AN lesions (p = 0.01).

CONCLUSION

AP lung lesions were significantly smaller and had a lower TDR than AN lesions. Spiculation was more frequent in small lesions. Non-solid >20 mm lesions may be ALK fusion-negative.

Histological subtype and smoking status, but not gender, are associated with epidermal growth factor receptor mutations in non-small-cell lung cancer

Mutations in epidermal growth factor receptor (EGFR) commonly occur in non-small-cell lung cancer (NSCLC) patients characterized by female gender, never-smoker status and adenocarcinoma histology. The aim of this study was to determine whether gender is a confounding factor for EGFR mutations in NSCLC. To elucidate the confounding effect, Pearson's χ² test and logistic regression models were used to correlate these characteristics with EGFR mutations in 426 NSCLC patients treated at our institutes. Of those 426 NSCLC patients, 47% were females, 57% were non-smokers and 84% had adenocarcinomas. The multivariate logistic regression analysis demonstrated that never-smoker status [odds ratio (OR)=3.49, 95% confidence interval (CI): 1.99-6.13; P<0.001)] and adenocarcinoma (OR=9.43, 95% CI 3.62-24.56; P<0.001) were associated with EGFR mutations; however, gender was not (OR=1.25, 95% CI: 0.73-2.15; P=0.416). Furthermore, gender was not associated with EGFR mutation subtypes (OR=1.19, 95% CI: 0.56-2.50; P=0.650). The frequency of EGFR mutations among females and males was not different in non-smokers (64.8 vs. 55.8%, P=0.204) or ever-smokers (27.8 vs. 24.2%, P=0.775). Therefore, if the assessment for EGFR mutation status was limited to non-smoking females with adenocarcinoma, up to 40% of the patients harboring EGFR mutations would be precluded from the benefit of EGFR inhibitor therapy. Our results indicated that gender is a confounding factor for EGFR mutations in NSCLC and suggested that gender may not be associated with tumorigenesis in NSCLC-harboring EGFR mutations.

Efficacy of epidermal growth factor receptor-tyrosine kinase inhibitors for Chinese patients with squamous cell carcinoma of lung harboring EGFR mutation

OBJECTIVE

Epidermal growth factor receptor (EGFR) mutation mostly occurred in lung adenocarcinoma, rarely in squamous cell carcinoma (SQCC). EGFR mutation rate in SQCC varied in previous reports, and the efficacy of EGFR tyrosine kinase inhibitors (TKIs) in SQCC harboring EGFR mutation has not yet been fully evaluated. The aim of this study was to investigate the efficacy EGFR-TKIs for Chinese patients with SQCC of lung harboring EGFR mutation.

PATIENTS AND METHODS

Two cohorts of patients were analyzed. The first cohort included 146 consecutive post-operation SQCC patients from January 2008 to October 2012. The second cohort included 63 patients with advanced SQCC receiving EGFR-TKIs treatment. EGFR mutation analysis was performed with Real-time PCR method. The pathologic diagnosis was validated with immunohistochemistry (IHC) for patients harboring activated EGFR mutation. And the efficacy of EGFR-TKIs in squamous cell carcinoma of lung (SQCC) was evaluated in patients with activated EGFR mutations.

RESULTS

In the first cohort, 146 resected patients, EGFR mutations were detected in 3 patients, with the mutation rate of 2.0%. In cohort two, 63 patients treated with EGFR-TKIs, 15 patients possessed activated EGFR mutations. The response rate and disease control rate in these patients was 26.7% and 66.7% respectively. 5 patients had disease control over 6 months. The progression free survival (PFS) in EGFR-mutated patients was 3.9 months.

CONCLUSIONS

In Chinese SQCC patients, EGFR mutation rate was extremely low. EGFR-TKIs seemed to be less effective in EGFR-mutated SQCC patients, but some patients could still obtain benefit from EGFR-TKIs. To identify this part of patients, further study was warranted in the future.

Differences in EGFR and KRAS mutation spectra in lung adenocarcinoma of never and heavy smokers

Epidermal growth factor receptor (EGFR) mutations are common in lung adenocarcinomas of never smokers, while KRAS mutations are more frequent among heavy smokers. Different clinicopathological and biological characteristics may, therefore, exist in lung adenocarcinoma according to smoking status. In the present study, a retrospective review was performed using 521 patients with surgically resected lung adenocarcinomas. The clinicopathological factors of age, gender, pathological tumor size, nodal status, lymphatic permeation and blood vessel invasion and the EGFR and KRAS mutation spectra were compared between never and heavy smokers. EGFR mutations were detected in 233 (45%) patients, while KRAS mutations were detected in 56 (11%) patients. EGFR-mutated adenocarcinomas had a higher prevalence of females in the never smokers compared with the heavy smokers (P<0.001). KRAS-mutated adenocarcinomas had a higher prevalence of females (P<0.001) and showed less frequent vascular invasion (P=0.018) in the never smokers compared with the heavy smokers. Minor EGFR mutations, excluding exon 21 L858R and exon 19 deletions, were more common in heavy smokers than never smokers (P=0.055). KRAS G to A transition was more common in never smokers, while KRAS G to T and G to C transversions were more common in heavy smokers (P=0.036). The clinicopathological characteristics and the spectra of the EGFR and KRAS mutations in lung adenocarcinoma were different between the never and heavy smokers. Further large-scale studies are required to evaluate the efficacy of molecular targeting agents with consideration to specific EGFR and KRAS mutations.

Molecular testing guideline for selection of lung cancer patients for EGFR and ALK tyrosine kinase inhibitors: guideline from the College of American Pathologists, International Association for the Study of Lung Cancer, and Association for Molecular Pathology

OBJECTIVE

To establish evidence-based recommendations for the molecular analysis of lung cancers that are required to guide EGFR- and ALK-directed therapies, addressing which patients and samples should be tested, and when and how testing should be performed.

PARTICIPANTS

Three cochairs without conflicts of interest were selected, one from each of the 3 sponsoring professional societies: College of American Pathologists, International Association for the Study of Lung Cancer, and Association for Molecular Pathology. Writing and advisory panels were constituted from additional experts from these societies.

EVIDENCE

Three unbiased literature searches of electronic databases were performed to capture published articles from January 2004 through February 2012, yielding 1533 articles whose abstracts were screened to identify 521 pertinent articles that were then reviewed in detail for their relevance to the recommendations. EVIDENCE was formally graded for each recommendation.

CONSENSUS PROCESS

Initial recommendations were formulated by the cochairs and panel members at a public meeting. Each guideline section was assigned to at least 2 panelists. Drafts were circulated to the writing panel (version 1), advisory panel (version 2), and the public (version 3) before submission (version 4).

CONCLUSIONS

The 37 guideline items address 14 subjects, including 15 recommendations (evidence grade A/B). The major recommendations are to use testing for EGFR mutations and ALK fusions to guide patient selection for therapy with an epidermal growth factor receptor (EGFR) or anaplastic lymphoma kinase (ALK) inhibitor, respectively, in all patients with advanced-stage adenocarcinoma, regardless of sex, race, smoking history, or other clinical risk factors, and to prioritize EGFR and ALK testing over other molecular predictive tests. As scientific discoveries and clinical practice outpace the completion of randomized clinical trials, evidence-based guidelines developed by expert practitioners are vital for communicating emerging clinical standards. Already, new treatments targeting genetic alterations in other, less common driver oncogenes are being evaluated in lung cancer, and testing for these may be addressed in future versions of these guidelines.

Molecular testing guideline for selection of lung cancer patients for EGFR and ALK tyrosine kinase inhibitors: guideline from the College of American Pathologists, International Association for the Study of Lung Cancer, and Association for Molecular Pathology

OBJECTIVE

To establish evidence-based recommendations for the molecular analysis of lung cancers that are that are required to guide EGFR- and ALK-directed therapies, addressing which patients and samples should be tested, and when and how testing should be performed.

PARTICIPANTS

Three cochairs without conflicts of interest were selected, one from each of the 3 sponsoring professional societies: College of American Pathologists, International Association for the Study of Lung Cancer, and Association for Molecular Pathology. Writing and advisory panels were constituted from additional experts from these societies.

EVIDENCE

Three unbiased literature searches of electronic databases were performed to capture articles published published from January 2004 through February 2012, yielding 1533 articles whose abstracts were screened to identify 521 pertinent articles that were then reviewed in detail for their relevance to the recommendations. Evidence was formally graded for each recommendation.

CONSENSUS PROCESS

Initial recommendations were formulated by the cochairs and panel members at a public meeting. Each guideline section was assigned to at least 2 panelists. Drafts were circulated to the writing panel (version 1), advisory panel (version 2), and the public (version 3) before submission (version 4).

CONCLUSIONS

The 37 guideline items address 14 subjects, including 15 recommendations (evidence grade A/B). The major recommendations are to use testing for EGFR mutations and ALK fusions to guide patient selection for therapy with an epidermal growth factor receptor (EGFR) or anaplastic lymphoma kinase (ALK) inhibitor, respectively, in all patients with advanced-stage adenocarcinoma, regardless of sex, race, smoking history, or other clinical risk factors, and to prioritize EGFR and ALK testing over other molecular predictive tests. As scientific discoveries and clinical practice outpace the completion of randomized clinical trials, evidence-based guidelines developed by expert practitioners are vital for communicating emerging clinical standards. Already, new treatments targeting genetic alterations in other, less common driver oncogenes are being evaluated in lung cancer, and testing for these may be addressed in future versions of these guidelines.

Analysis of intratumor heterogeneity of EGFR mutations in mixed type lung adenocarcinoma

BACKGROUND

Epidermal growth factor receptor mutations are predictive of the success of EGFR tyrosine kinase inhibitor treatment in patients with advanced non--small-cell lung cancer. As with other solid tumors, lung cancer is thought to be the result of an accumulation of genetic alterations after exposure to carcinogens. The aim of the present study was to clarify the relationship between multistep carcinogenesis and the accumulation of EGFR mutations.

PATIENTS AND METHODS

The intratumor heterogeneity of EGFR mutations was analyzed in 38 patients with resected mixed-type lung adenocarcinoma according to histological patterns, and the clinical features of the patients harboring intratumor heterogeneity of EGFR mutations were evaluated.

RESULTS

Intratumor heterogeneity of EGFR mutations was detected in 9 of 38 tumors. EGFR mutations were more common in the bronchioloalveolar (lepidic) carcinoma pattern than in the papillary and acinar patterns, although this difference was not significant. However, there was a significant correlation between intratumor heterogeneity of EGFR mutations and smoking history (P < .043).

CONCLUSION

Intratumor heterogeneity of EGFR mutations correlates with the distribution of histological subtype in mixed type adenocarcinoma and is associated with smoking history.

How sensitive are epidermal growth factor receptor-tyrosine kinase inhibitors for squamous cell carcinoma of the lung harboring EGFR gene-sensitive mutations?

INTRODUCTION

Epidermal growth factor receptor (EGFR) mutations are found mostly in adenocarcinoma, and rarely in squamous cell carcinoma (SQC). Little is known about SQC harboring EGFR mutations.

METHODS

Between April 2006 and October 2010, we investigated the incidence of EGFR activating mutations in SQC of the lung using the peptide nucleic acid-locked nucleic acid polymerase chain reaction clamp method. The efficacy of EGFR-tyrosine kinase inhibitors (TKIs) was retrospectively evaluated in patients with EGFR-mutated SQC. Further pathologic analyses were performed using immunohistochemistry.

RESULTS

Thirty-three of 249 patients with SQC (13.3%) had EGFR mutations, including exon 19 deletion (19 of 33 patients, 58%), L858R point mutation in exon 21 (12 of 33, 36%), and G719S point mutation in exon 18 (2 of 33, 6%). Twenty of these 33 patients received EGFR-TKI therapy, and five of these 20 responded to EGFR-TKIs with a response rate of 25.0% (95% confidence interval [CI], 8.7%-49.1%). The patients' median progression-free survival and median overall survival were 1.4 months (95% CI, 0.7-5.8 months) and 14.6 months (95% CI, 2.9-undeterminable months), respectively. Approximately one third of the EGFR-mutated SQC patients achieved progression-free survival for longer than 6 months. Some of these patients had high carcinoembryonic antigen levels or a history of never smoking, or were positive for thyroid transcription factor-1.

CONCLUSIONS

Although EGFR-TKIs seem to be generally less effective in EGFR-mutated SQC than in EGFR-mutated adenocarcinoma, some EGFR-mutated SQC patients can obtain clinical benefit from EGFR-TKIs. To better identify these patients, not only EGFR mutation status, but also clinical factors and pathologic findings should be taken into consideration.

Molecular testing guideline for selection of lung cancer patients for EGFR and ALK tyrosine kinase inhibitors: guideline from the College of American Pathologists, International Association for the Study of Lung Cancer, and Association for Molecular Pathology

OBJECTIVE

To establish evidence-based recommendations for the molecular analysis of lung cancers that are required to guide EGFR- and ALK-directed therapies, addressing which patients and samples should be tested, and when and how testing should be performed.

PARTICIPANTS

Three cochairs without conflicts of interest were selected, one from each of the 3 sponsoring professional societies: College of American Pathologists, International Association for the Study of Lung Cancer, and Association for Molecular Pathology. Writing and advisory panels were constituted from additional experts from these societies.

EVIDENCE

Three unbiased literature searches of electronic databases were performed to capture articles published from January 2004 through February 2012, yielding 1533 articles whose abstracts were screened to identify 521 pertinent articles that were then reviewed in detail for their relevance to the recommendations. Evidence was formally graded for each recommendation.

CONSENSUS PROCESS

Initial recommendations were formulated by the cochairs and panel members at a public meeting. Each guideline section was assigned to at least 2 panelists. Drafts were circulated to the writing panel (version 1), advisory panel (version 2), and the public (version 3) before submission (version 4).

CONCLUSIONS

The 37 guideline items address 14 subjects, including 15 recommendations (evidence grade A/B). The major recommendations are to use testing for EGFR mutations and ALK fusions to guide patient selection for therapy with an epidermal growth factor receptor (EGFR) or anaplastic lymphoma kinase (ALK) inhibitor, respectively, in all patients with advanced-stage adenocarcinoma, regardless of sex, race, smoking history, or other clinical risk factors, and to prioritize EGFR and ALK testing over other molecular predictive tests. As scientific discoveries and clinical practice outpace the completion of randomized clinical trials, evidence-based guidelines developed by expert practitioners are vital for communicating emerging clinical standards. Already, new treatments targeting genetic alterations in other, less common driver oncogenes are being evaluated in lung cancer, and testing for these may be addressed in future versions of these guidelines.

Mutations of the EGFR and K-ras genes in resected stage I lung adenocarcinoma and their clinical significance

PURPOSE

This study retrospectively assessed the mutations of the epidermal growth factor receptor (EGFR) and K-ras genes and their clinical significance in patients with resected stage I adenocarcinomas.

METHODS

A total of 354 patients with resected lung adenocarcinomas were included, and 256 patients with stage I disease were analyzed for the prognostic and predictive value of these mutations.

RESULTS

Mutations of EGFR and K-ras genes were detected in 149 (41.1 %) and 23 (6.4 %) of all tumors, and in 122 (47.6 %) and 14 (5.5 %) of stage I tumors, respectively. There were no significant differences in the disease-free survival (DFS) and overall survival (OS) between the EGFR-mutant and wild-type groups. However, the DFS and OS were significantly shorter in patients with K-ras mutations than in those without (5-year DFS: 50.8 vs. 76.9 %, 5-year OS: 70.0 vs. 86.6 %, p < 0.01). A multivariate analysis showed that K-ras mutations were an independent poor prognostic factor. Twenty-four of the 41 patients with recurrent disease after surgery were treated with an EGFR-TKI. Fifteen EGFR-mutant patients treated with an EGFR-TKI had a better prognosis than did the nine EGFR-wild-type patients.

CONCLUSION

The presence of an EGFR gene mutation was a predictive factor for the response to EGFR-TKI treatment in patients with resected stage I adenocarcinoma, but was not a prognostic factor. The presence of a K-ras gene mutation was a poor prognostic factor.

Distinct profile of driver mutations and clinical features in immunomarker-defined subsets of pulmonary large-cell carcinoma

Pulmonary large-cell carcinoma-a diagnostically and clinically controversial entity-is defined as a non-small-cell carcinoma lacking morphologic differentiation of either adenocarcinoma or squamous cell carcinoma, but suspected to represent an end stage of poor differentiation of these tumor types. Given the recent advances in immunohistochemistry to distinguish adenocarcinoma and squamous cell carcinoma, and the recent insights that several therapeutically relevant genetic alterations are distributed differentially in these tumors, we hypothesized that immunophenotyping may stratify large-cell carcinomas into subsets with distinct profiles of targetable driver mutations. We therefore analyzed 102 large-cell carcinomas by immunohistochemistry for TTF-1 and ΔNp63/p40 as classifiers for adenocarcinoma and squamous cell carcinoma, respectively, and correlated the resulting subtypes with nine therapeutically relevant genetic alterations characteristic of adenocarcinoma (EGFR, KRAS, BRAF, MAP2K1/MEK1, NRAS, ERBB2/HER2 mutations and ALK rearrangements) or more common in squamous cell carcinoma (PIK3CA and AKT1 mutations). The immunomarkers classified large-cell carcinomas as variants of adenocarcinoma (n=62; 60%), squamous cell carcinoma (n=20; 20%) or marker-null (n=20; 20%). Genetic alterations were found in 38 cases (37%), including EGFR (n=1), KRAS (n=30), BRAF (n=2), MAP2K1 (n=1), ALK (n=3) and PIK3CA (n=1). All molecular alterations characteristic of adenocarcinoma occurred in tumors with immunoprofiles of adenocarcinoma or marker-null, but not in tumors with squamous immunoprofiles (combined mutation rate 50% vs 30% vs 0%, respectively; P<0.001), whereas the sole PIK3CA mutation occurred in a tumor with squamous profile (5%). Furthermore, marker-null large-cell carcinomas were associated with significantly inferior disease-free (P<0.001) and overall (P=0.001) survival. In conclusion, the majority (80%) of large-cell carcinomas can be classified by immunomarkers as variants of adenocarcinoma or squamous cell carcinoma, which stratifies these tumors into subsets with a distinct distribution of driver mutations and distinct prognoses. These findings have practical implications for diagnosis, predictive molecular testing and therapy selection.

Cancer genes in lung cancer: racial disparities: are there any?

Cancer is now known as a disease of genomic alterations. Mutational analysis and genomics profiling in recent years have advanced the field of lung cancer genetics/genomics significantly. It is becoming more accepted now that the identification of genomic alterations in lung cancer can impact therapeutics, especially when the alterations represent "oncogenic drivers" in the processes of tumorigenesis and progression. In this review, we will highlight the key driver oncogenic gene mutations and fusions identified in lung cancer. The review will summarize and report the available demographic and clinicopathological data as well as molecular details behind various lung cancer gene alterations in the context of race. We hope to shed some light into the disparities in the incidence of various genetic mutations among lung cancer patients of different racial backgrounds. As molecularly targeted therapy continues to advance in lung cancer, racial differences in specific genetic/genomic alterations can have an important impact in the choices of therapeutics and in our understanding of the drug sensitivity/resistance profile. The most relevant genes in lung cancer described in this review include the following: EGFR, KRAS, MET, LKB1, BRAF, PIK3CA, ALK, RET, and ROS1. Commonly identified genetic/genomic alterations such as missense or nonsense mutations, small insertions or deletions, alternative splicing, and chromosomal fusion rearrangements were discussed. Relevance in current targeted therapeutic drugs was mentioned when appropriate. We also highlighted various targeted therapeutics that are currently under clinical development, such as the MET inhibitors and antibodies. With the advent of next-generation sequencing, the landscape of genomic alterations in lung cancer is expected to be much transformed and detailed in upcoming years. These genomic landscape differences in the context of racial disparities should be emphasized both in tumorigenesis and in drug sensitivity/resistance. It is hoped that such effort will help to diminish racial disparities in lung cancer outcome in the future.

Association of epidermal growth factor receptor and K-Ras mutations with smoking history in non-small cell lung cancer patients

Lung cancer, a major health problem affecting the epithelial lining of the lower respiratory tract, is considered to be one of the deadliest types of cancer in males and females and it is well-known that smoking is the chief cause of lung cancer. In addition to smoking and environmental factors, genetic susceptibility may also contribute to the development of lung cancer. Previous studies have shown that certain non-small cell lung cancer (NSCLC) patients harbor gain-of-function mutations in the epidermal growth factor receptor gene (EGFR). Phosphorylated EGFR triggers the activation of intracellular signal transduction pathways, including the RAS-MAPK, PI3K-Akt and STAT pathways. However, K-Ras gene point mutations in codons 12, 13 or 61 cause the inactivation of GTPase activity which results in overstimulation of cellular growth and gives rise to neoplastic development. Our aim was to investigate the presence and association of EGFR and K-Ras mutations in 50 primary NSCLC patients with a smoking history by using real-time PCR and sequencing. EGFR mutations were detected in four patients (8%). Two of these mutations were L858R mutations and the remaining two were deletion mutations spanning between codons 746 and 750. The L858R mutation was significantly associated with smoking status (P=0.003). K-Ras codon 12 and 61 mutations were also observed in four patients. However, no association was observed between K-Ras mutations and the tumor staging, gender, histology and smoking status of the patients.

Molecular epidemiology of EGFR and KRAS mutations in 3,026 lung adenocarcinomas: higher susceptibility of women to smoking-related KRAS-mutant cancers

PURPOSE

The molecular epidemiology of most EGFR and KRAS mutations in lung cancer remains unclear.

EXPERIMENTAL DESIGN

We genotyped 3,026 lung adenocarcinomas for the major EGFR (exon 19 deletions and L858R) and KRAS (G12, G13) mutations and examined correlations with demographic, clinical, and smoking history data.

RESULTS

EGFR mutations were found in 43% of never smokers and in 11% of smokers. KRAS mutations occurred in 34% of smokers and in 6% of never smokers. In patients with smoking histories up to 10 pack-years, EGFR predominated over KRAS. Among former smokers with lung cancer, multivariate analysis showed that, independent of pack-years, increasing smoking-free years raise the likelihood of EGFR mutation. Never smokers were more likely than smokers to have KRAS G > A transition mutation (mostly G12D; 58% vs. 20%, P = 0.0001). KRAS G12C, the most common G > T transversion mutation in smokers, was more frequent in women (P = 0.007) and these women were younger than men with the same mutation (median 65 vs. 69, P = 0.0008) and had smoked less.

CONCLUSIONS

The distinct types of KRAS mutations in smokers versus never smokers suggest that most KRAS-mutant lung cancers in never smokers are not due to second-hand smoke exposure. The higher frequency of KRAS G12C in women, their younger age, and lesser smoking history together support a heightened susceptibility to tobacco carcinogens.

Synergism of EGFR and c-Met pathways, cross-talk and inhibition, in non-small cell lung cancer

Background

c-Met and EGFR receptors are widely expressed on cancer cells; they are implicated in the development and progression of cancer through a plethora of effects on cell cycle progression, apoptosis, motility and metastasis and are potential targets for combination therapy. EGFR receptor tyrosine kinases are currently being targeted in a number of malignancies.

Methods

Apoptosis was studied by FACS analysis using propidium iodide. EGF and HGF signaling intermediates were studied by western blotting. Cell proliferation was determined by MTT assays. Cell motility was done by time lapse confocal microscopy.

Results

c-Met and EGFR were both expressed in A549, H1838, H2170, SW900, SW1573, H358, SKLU-1, and H1993 non small cell lung cancer (NSCLC) cell lines. Both EGF and HGF at 100 ng/ml in medium showed a synergistic effect on cell proliferation at 48–72 h as seen by a proliferation assay in A549, H1838, and SKMES cells. In A549 and H1838 cell lines, HGF (40 ng/ml) and EGF (5 ng/ml) induced synergistic phosphorylation on c-Met (Tyr 1003/1230/1234/1235). Additionally, synergistic phosphorylation of Akt (Ser-473) and phospho-ERK1+ERK2 (Thr202/Tyr204) was also seen indicating that EGF and HGF could induce synergistic phosphorylation of important signaling intermediates. Treatment with EGF and HGF at 100 ng/ml for 2 h also leads to an additive effect in inducing cell motility (especially membrane ruffling) in H1993 cells. A novel c-Met small molecule tyrosine kinase inhibitor SU11274 and EGFR tyrosine kinase inhibitors Tyrphostin AG1478 and gefitinib (Iressa) were tested to study their effect in combination on proliferation and apoptosis in lung cancer cells. Interestingly, a synergistic effect on inhibition of cell proliferation was seen in the presence of SU11274 and Tyrphostin AG1478. 0.5 µM Tyrphostin AG1478 and 2 µM SU11274 inhibited growth by 21% and 25%, respectively; a combination of both tyrosine kinase inhibitors inhibited growth by 65%. Interestingly, EGFR inhibitor (gefitinib, Iressa) and c-Met inhibitor (SU11274) also had a synergistic effect on apoptosis in H358 cells.

Conclusion

There was a synergistic effect of EGF and HGF on proliferation, downstream activation of signal transduction and an additive effect seen on motility. These studies show that a combination of HGF and EGF tyrosine kinase inhibitors on NSCLC, could potentially be targeted in a synergistic fashion.

Response to erlotinib in patients with EGFR mutant advanced non-small cell lung cancers with a squamous or squamous-like component

We previously reported that although EGFR mutations are not a feature of pure squamous cell carcinomas (SCC) of the lung, these mutations do occur in adenosquamous carcinomas (AD-SCC) and in rare solid adenocarcinomas, both of which can mimic SCC in small samples. Here we present an expanded series of these cases with a focus on sensitivity to erlotinib. The study included 13 patients with EGFR mutant lung carcinomas, which after detailed pathologic review were classified as AD-SCC (n = 11) or solid adenocarcinoma (n = 2). The majority received a diagnosis of SCC in at least 1 sample. All patients were treated with erlotinib. Eight of 11 patients with AD-SCC were evaluable for response. Their overall response rate was 88% (7/8; 95% CI, 47% to 99%). One of 2 solid adenocarcinoma patients responded to erlotinib. As a group, median progression-free survival was 12 months (95% CI, 8 to not reached); median overall survival was 29 months (95% CI, 27 to not reached). In conclusion, EGFR mutant AD-SCC and solid adenocarcinoma show a response to erlotinib that is comparable to that seen in patients with conventional adenocarcinoma. These tumors can mimic SCC in small samples. We propose an approach to increase the capture of these rare histology patients for EGFR mutation testing.