Squamous cell carcinoma of the lung compared with other histotypes shows higher messenger RNA and protein levels for thymidylate synthase

ERCC1 and BRAC1 mRNA expression levels in the primary tumor could predict the effectiveness of the second-line cisplatin-based chemotherapy in pretreated patients with metastatic non-small cell lung cancer

INTRODUCTION

The potential predictive role of BRCA1 and ERCC1 expression levels in patients with metastatic non-small cell lung cancer (NSCLC) receiving second-line platinum-based chemotherapy was investigated.

METHODS

Real-time quantitative polymerase chain reaction after reverse transcription was used to assess the expression levels of BRCA1 and ERCC1 in 100 microdissected primary tumors from platinum-naive NSCLC patients treated with platinum-based chemotherapy in the second-line setting.

RESULTS

Low ERCC1 mRNA levels were significantly associated with higher response rate (p = 0.011), longer median progression-free survival (PFS; p = 0.029), and median overall survival (mOS; p = 0.001) after the initiation of the second-line treatment. Similarly, low BRCA1 expression level was significantly correlated with higher response rate (p = 0.022), longer PFS (p = 0.041), and mOS (p = 0.005). In addition, patients with low ERCC1 and BRCA1 mRNA experienced increased median PFS (p = 0.021) and mOS (p < 0.001) in comparison with those who had both genes upregulated. A multivariate analysis revealed that low ERCC1 and low BRCA1 expression levels were significantly associated with increased PFS (hazard ratio [HR]: 0.6; 95% confidence interval [CI]: 0.4-0.8; p = 0.029 and HR: 0.7; 95% CI: 0.6-0.9; p = 0.043, respectively) and OS (HR: 0.5; 95% CI: 0.3-0.7; p = 0.003 and HR: 0.7; 95% CI: 0.6-0.9; p = 0.038, respectively).

CONCLUSIONS

These results suggest that the ERCC1 and BRCA1 mRNA expression levels in the primary tumor at the time of diagnosis could be used for the prediction of platinum sensitivity in the treatment of NSCLC in the second-line setting. Cross-validation studies are warranted.

A decade of advances in treatment for advanced non-small cell lung cancer

The last decade has heralded a paradigm shift in the evaluation and treatment of advanced non-small cell lung cancer (NSCLC). No longer are patients with NSCLC considered a homogeneous population treated in the same way; rather, clinical characteristics, histology, and an expanding array of molecular markers are increasingly being used to individualize therapy. Both histology and tumor epidermal growth factor receptor mutational status currently have firmly established roles in determining initial and salvage therapy for advanced NSCLC. Several other biomarkers are the focus of ongoing prospective randomized clinical trials customizing both traditional chemotherapy and newer molecularly targeted agents.

Pemetrexed plus platinum as the first-line treatment option for advanced non-small cell lung cancer: a meta-analysis of randomized controlled trials

To compare the efficacy and toxicities of pemetrexed plus platinum with other platinum regimens in patients with previously untreated advanced non-small cell lung cancer (NSCLC). Methods: A meta-analysis was performed using trials identified through PubMed, EMBASE, and Cochrane databases. Two investigators independently assessed the quality of the trials and extracted data. The outcomes included overall survival (OS), progression-free survival (PFS), response rate (RR), and different types of toxicity. Hazard ratios (HRs), odds ratios (ORs) and their 95% confidence intervals (CIs) were pooled using RevMan software. Results: Four trials involving 2,518 patients with previously untreated advanced NSCLC met the inclusion criteria. Pemetrexed plus platinum chemotherapy (PPC) improved survival compared with other platinum-based regimens (PBR) in patients with advanced NSCLC (HR = 0.91, 95% CI: 0.83–1.00, p = 0.04), especially in those with non-squamous histology (HR = 0.87, 95% CI: 0.77–0.98, p = 0.02). No statistically significant improvement in either PFS or RR was found in PPC group as compared with PBR group (HR = 1.03, 95% CI: 0.94–1.13, p = 0.57; OR = 1.15, 95% CI: 0.95–1.39, p = 0.15, respectively). Compared with PBR, PPC led to less grade 3–4 neutropenia and leukopenia but more grade 3–4 nausea. However, hematological toxicity analysis revealed significant heterogeneities. Conclusion: Our results suggest that PPC in the first-line setting leads to a significant survival advantage with acceptable toxicities for advanced NSCLC patients, especially those with non-squamous histology, as compared with other PRB. PPC could be considered as the first-line treatment option for advanced NSCLC patients, especially those with non-squamous histology.

Ribonucleotide reductase large subunit (RRM1) gene expression may predict efficacy of adjuvant mitotane in adrenocortical cancer

PURPOSE

Mitotane is the most broadly used systemic therapy for adrenocortical carcinoma (ACC), but its mechanism of action and possible predictors of treatment response are currently poorly defined. Our aim was to evaluate the gene expression of ribonucleotide reductase large subunit 1 (RRM1) and excision repair cross-complementation group 1 (ERCC1) in ACC as potential biomarkers for clinical outcome and response to mitotane.

EXPERIMENTAL DESIGN

Forty-five and 47 tissue samples from two cohorts (Orbassano, Italy; Wuerzburg, Germany) of completely resected ACC were centrally analyzed using real-time PCR for RRM1 and ERCC1 expression. Fifty-four patients received surgery alone and 38 received adjuvant mitotane after surgery. Clinical and pathologic features were highly comparable in the two series. H295R and SW-13 ACC cell lines were also used for pharmacologic tests.

RESULTS

ERCC1 gene expression was not associated to clinical outcome. In contrast, high RRM1 gene expression was associated to shorter disease-free survival (DFS) and overall survival at both univariate and multivariate analysis. In patients with low RRM1 gene expression, adjuvant mitotane was associated with improved DFS, whereas this effect was lost in cases with high RMM1 expression. In vitro mitotane induced strong up regulation of RRM1 transcription (up to 25-fold increase) in mitotane-insensitive SW-13 but not in mitotane-sensitive H295R cells. Furthermore, RRM1 silencing in SW-13 cells induced sensitivity to mitotane.

CONCLUSION

Our in vitro and in vivo data indicate that RRM1 gene expression is functionally associated to mitotane sensitivity and support a possible role of RRM1 determination as a novel molecular biomarker predicting response to adjuvant mitotane in ACC.

Human achaete-scute homolog-1 expression in neuroendocrine breast carcinoma

Neuroendocrine (NE) breast carcinoma is defined by morphological features similar to those of NE tumors of other organs and NE marker expression in at least 50 % of neoplastic cells. However, a NE morphology may be observed even in breast carcinomas lacking NE markers. Human achaete-scute homolog-1 (hASH-1) is a transcription factor that plays a key role in the regulation of mammalian neural and NE cell development and has been identified in several human NE tumors. The aim of this study was to investigate hASH-1 expression in human breast cancers. hASH-1 expression was evaluated in 482 consecutive non-NE invasive breast carcinomas, in a series of 84 breast cancers with >50 % NE marker expression (high NE differentiation) and 21 carcinomas with NE histology but negative or focally (<50 %) positive for NE markers (low NE differentiation). hASH-1 protein was evaluated by a specific monoclonal antibody using immunohistochemistry and gene expression by real-time polymerase chain reaction. None of the non-NE invasive breast carcinomas expressed hASH-1 at any levels. hASH-1 was expressed in tumor cell nuclei of 63 and 38 % of cases with high and low NE differentiation, respectively. Strong correlation with protein and gene expression levels was observed (p < 0.0001). hASH-1 expression was correlated to a low mitotic count (p = 0.02) and a low Ki67 proliferative index (p = 0.0062). hASH-1 expression occurs in breast cancers with NE differentiation regardless of the extent of the NE cell population, and it is restricted to a subset of tumor cells having a low proliferative potential.

Safety and efficacy of pemetrexed in maintenance therapy of non-small cell lung cancer

Lung cancer incidence continues to rise and is the number one cause of cancer death in both men and women worldwide with projected 221,130 new cases and 156,940 deaths in the United States in 2011.1 Non-small cell lung cancer (NSCLC) represents more than 85% of the cases with most patients having either locally advanced or metastatic disease at the time of initial diagnosis, and approximately 60%-70% of them have an adenocarcinoma histologic subtype. In the last three years, we have seen several advances in the management of NSCLC, with several factors playing an important role in the treatment decision making process. Maintenance therapy has been added to the algorithm of NSCLC management and Pemetrexed has been studied as single agent or in combination in this setting with recent studies showing safety and improved progression free survival (PFS) and/or overall survival (OS), still the disease for the most part has a dismal outcome. More research work needs to be done to identify which patients truly benefit from these approaches, and to whom we should offer maintenance or switch maintenance vs. close observation.

The optimal chemotherapy for stage III non-small cell lung cancer patients

Nearly one third of non-small cell lung cancer (NSCLC) patients at diagnosis have stage III disease. Concurrent chemoradiation has emerged as the standard of care for patients with unresectable stage III NSCLC. Meta-analyses of studies comparing concurrent with sequential therapy showed that there was a relative improvement of about 20% with concurrent therapy over sequential therapy in these patients and that concurrent chemoradiation is more toxic than the sequential approach, particularly with regard to esophagitis. The incidence of pneumonitis is not significantly higher with concurrent therapy. All the phase 3 trials comparing concurrent with sequential therapy included cisplatin-based therapy. In addition, patients enrolled in these studies were required to have good performance status and some studies mandated limited weight loss. Some patients are also treated with lower doses of chemotherapy, particularly carboplatin and paclitaxel, concurrently with radiation followed by full-dose chemotherapy. Randomized studies have failed to show benefit of induction or consolidation chemotherapy. For patients who have a poor performance status or significant weight loss, a sequential approach of chemotherapy followed by radiation may be appropriate. Ongoing clinical trials are evaluating the utility of integrating some of the newer agents such as pemetrexed and cetuximab into the treatment plan for stage III patients.

Inhibition of dUTPase induces synthetic lethality with thymidylate synthase-targeted therapies in non-small cell lung cancer

Chemotherapies that target thymidylate synthase (TS) continue to see considerable clinical expansion in non-small cell lung cancer (NSCLC). One drawback to TS-targeted therapies is drug resistance and subsequent treatment failure. Novel therapeutic and biomarker-driven strategies are urgently needed. The enzyme deoxyuridine triphosphate nucleotidohydrolase (dUTPase) is reported to protect tumor cells from aberrant misincorporation of uracil during TS inhibition. The goal of this study was to investigate the expression and significance of dUTPase in mediating response to TS-targeted agents in NSCLC. The expression of dUTPase in NSCLC cell lines and clinical specimens was measured by quantitative real-time reverse transcriptase PCR and immunohistochemistry. Using a validated RNA interference approach, dUTPase was effectively silenced in a panel of NSCLC cell lines and response to the fluoropyrimidine fluorodeoxyuridine (FUdR) and the antifolate pemetrexed was analyzed using growth inhibition and clonogenic assays. Apoptosis was analyzed by flow cytometry. Significant variation in the quantity and cellular expression of dUTPase was observed, including clear evidence of overexpression in NSCLC cell line models and tumor specimens at the mRNA and protein level. RNA interference-mediated silencing of dUTPase significantly sensitized NSCLC cells to growth inhibition induced by FUdR and pemetrexed. This sensitization was accompanied by a significant expansion of intracellular dUTP pools and significant decreases in NSCLC cell viability evaluated by clonogenicity and apoptotic analyses. Together, these results strongly suggest that uracil misincorporation is a potent determinant of cytotoxicity to TS inhibition in NSCLC and that inhibition of dUTPase is a mechanism-based therapeutic approach to significantly enhance the efficacy of TS-targeted chemotherapeutic agents.

Significance of thymidylate synthase and thyroid transcription factor 1 expression in patients with nonsquamous non-small cell lung cancer treated with pemetrexed-based chemotherapy

INTRODUCTION

This study is to evaluate whether thymidylate synthase (TS) or thyroid transcription factor 1 (TTF1) protein expression can predict clinical outcomes for pemetrexed-based chemotherapy in patients with nonsquamous non-small cell lung cancer (NSCLC).

METHODS

Two hundred eighty-five consecutive patients with nonsquamous NSCLC treated with pemetrexed-based chemotherapy were immunohistochemically analyzed for the expressions of TS and TTF1.

RESULTS

TS and TTF1 expression were successfully analyzed in 193 and 284 cases, respectively. Tumors with TS-negativity or TTF1-positivity were more frequent in patients who were female, younger, had adenocarcinoma, or had never smoked. Higher response rates for pemetrexed-based chemotherapy were associated with TS-negativity (33.7% versus 14.1%, p = 0.002) and TTF1-positivity (28.1% versus 9.8%, p < 0.001). In univariate analysis, progression-free survival for pemetrexed-based chemotherapy was significantly longer in groups with adenocarcinoma (2.9 versus 1.4 months, p = 0.001), TS-negativity (4.1 versus 2.0 months, p = 0.001), and TTF1-positivity (3.8 versus 1.3 months, p < 0.001). In multivariate analysis, TS-negativity (hazard ratio [HR] = 0.70; 95% confidence interval [CI], 0.51-0.97) and TTF1-positivity (HR = 0.51; 95% CI, 0.35-0.73) were associated with longer progression-free survival. Patients with TTF1-positive tumors also had significantly longer overall survival times than patients with TTF1-negative tumors (25.4 versus 14.2 months, HR = 0.55; 95% CI, 0.39-0.77).

CONCLUSIONS

Low TS or high TTF1 protein expression was significantly associated with better clinical outcomes in nonsquamous NSCLC patients who were treated with pemetrexed-based chemotherapy. The predictive role of TS or TTF1 expression should be further validated in a prospective randomized study.

Maintenance Therapy for NSCLC: Consensus and Controversy

Nowadays, advanced non-small cell lung cancer (NSCLC) is still an incurable disease. However, recent researches on maintenance therapy have led to considerable progress. Recently, pemetrexed and erlotinib have been approved for maintenance chemotherapy by both the U.S. Food and Drug Administration and European Medicines Agency. However, there are not adequate data to support the maintenance therapy as the standard treatment for advanced NSCLC and there has been no conclusive predictor of who will get benefit from maintenance chemotherapy and what type of maintenance, continuation or switch, is preferred. This article reviews the main studies on maintenance therapy of advanced NSCLC and discusses the results available to date.

S-1 monotherapy for previously treated non-small cell lung cancer: A retrospective analysis by age and histopathological type

S-1, an oral fluoropyrimidine derivative, has been approved for the treatment of non-small cell lung cancer (NSCLC) in Japan. In the present study, the efficacy and safety of S-1 monotherapy for elderly patients with previously treated NSCLC were retrospectively evaluated, and the efficacy of S-1 monotherapy was compared by histopathological type. This retrospective study included 54 patients with advanced or recurrent NSCLC who had received S-1 monotherapy following the failure of previous chemotherapy regimens at our institutes. Patient outcomes were compared based on their age and histopathological type. S-1 was administered orally, twice daily, while the duration and interval were modified according to the medical condition of each patient. The default delivery schedule, the mean number of S-1 cycles, did not differ significantly between the two age groups (<70 and ≥70 years). The rate of therapy discontinuation, schedule modification or dose reduction due to intolerable toxicities or patient refusal was relatively frequent in the older group (40.7 and 55.6% for ages <70 and ≥70 years, respectively; p=0.414), and the incidence of grade 3 anemia was relatively high in the older group (3.7 and 18.5%, respectively; p=0.192). The response rates (13.0 and 4.8%, respectively; p=0.609) and disease control rates (39.1 and 33.3%, respectively; p=0.761) did not differ significantly between the two age groups. According to histopathological type, the disease control rate was significantly higher in adenocarcinoma (57.9%) compared to non-adenocarcinoma (20.0%, p=0.013). Thus, S-1 monotherapy may be equally effective and tolerated in patients <70 years and those ≥70 years. Additionally, adenocarcinoma may have a higher disease control rate than non-adenocarcinoma.

Mutation and expression of multiple treatment response-related genes in a population with locally advanced non-small cell lung cancer

Individual therapy based on various pathohistological types and biological characteristics may be the practical trend of advanced non-small cell lung cancer (NSCLC) treatment. To provide a molecular criterion for drug selection, we investigated the incidence of somatic mutation and mRNA expression levels of common genes relevant to treatment response in a population with locally advanced NSCLC. Mutant-enriched and branched DNA-liquidchip technology (bDNA-LCT) were used to detect the somatic mutations in the epidermal growth factor receptor (EGFR), KRAS, BRAF and phosphatidylinositol-3-kinase catalytic α (PIK3CA) genes, and mRNA levels of EGFR, ERCC1, class III β-tubulin (TUBB3) and TYMS, separately, in paraffin tissue blocks from 30 patients with stage IIIA NSCLC. Our current findings revealed that 6, 4 and 2 out of 30 samples were found with mutations in exons 19, 21 and 20 of the EGFR gene, respectively. The mutation incidence of exons 19 and 21 had a positive correlation with EGFR mRNA expression. Mutations in exons 12 and 13 of the K-ras gene were found in 2 out of 30, and 1 out of 30 samples, separately. Three out of 30 samples were found with mutations in codon 542 of the PIK3CA gene. No mutations were found in the BRAF gene. The expression levels of ERCC1 and TUBB3 mRNAs were higher in patients with adenocarcinoma than those in patients with squamous cell carcinoma. The expression of TYMS mRNA in patients with adenocarcinoma was lower than that in patients with squamous cell carcinoma. In conclusion, mutations and mRNA expression of these commonly studied genes provides a basis for the selection of suitable molecular markers for individual treatment in a population with locally advanced NSCLC.

Customizing systemic therapy in patients with advanced non-small cell lung cancer

Lung cancer is the leading cause of cancer deaths worldwide. Standard chemotherapy has been shown to improve quality of life and has a modest influence on overall survival. This modest improvement in survival is partly due to the choice of chemotherapy regimens that have been based on prognostic factors such as age, performance status and comorbidities of the patient. This underlines the importance of developing a more personalized therapy for patients with non-small cell lung cancer. Such an approach may reduce the variation in how individual patients respond to medications by tailoring therapies to their genetic profile. In this review we focus on several aspects of customized therapy, looking not only at patient characteristics but also to tumor histology and specific tumor biomarkers.

How to integrate current knowledge in selecting patients for first line in NSCLC?

Non-small-cell lung cancer (NSCLC) accounts for 80% of all lung cancer, which is the leading cause of cancer mortality. The majority of NSCLC patients present with advanced disease at diagnosis. Standard chemotherapy using platinum-containing doublets has reached a therapeutic plateau with a median survival of ~1 year. The development of more effective strategies in the first-line setting remains challenging. In selected chemotherapy-naïve, advanced, non-squamous patients, the combination of bevacizumab with chemotherapy was shown to produce better outcomes than chemotherapy alone. The potential benefit of maintenance/sequential treatment after initial platinum-based chemotherapy should be discussed in detail with each patient. Epidermal growth factor receptor (EGFR) mutation determination should be carried out in subgroups of patients characterized by a high prevalence of sensitizing mutations. When a mutation is present, first-line treatment with an EGFR tyrosine kinase inhibitor may be considered. Finally, a phase I study using an oral ALK inhibitor has produced promising results in NSCLC patients with ALK rearrangements, indicating that ALK represents a new therapeutic target in a molecularly defined subset of NSCLC. Ongoing studies in first-line therapy are focusing on targeted therapies and patient selection.

Phase II study of pemetrexed and cisplatin, with chest radiotherapy followed by docetaxel in patients with stage III non-small cell lung cancer

BACKGROUND

Pemetrexed has emerged as one of the most active agents for the treatment of patients with advanced non-small cell lung cancer (NSCLC). We conducted a phase II study to assess the efficacy and feasibility of integrating pemetrexed in a concurrent therapy plan for patients with stage III NSCLC.

METHODS

Patients with stage III NSCLC with performance status 0 to 1, adequate organ function including pulmonary function, and V20 less than 40% were eligible. Patients were treated with cisplatin 75 mg/m² (first five patients 60 mg/m²) and pemetrexed 500 mg/m² every 21 days for three cycles with chest radiotherapy to 66 Gy. Patients then received three cycles of docetaxel 75 mg/m² every 21 days. Tumors were analyzed for Excision Repair Cross Complementation Group 1 and thymidylate synthase.

RESULTS

Patient characteristics (N = 28) were median age, 60; males, 68%; stage IIIB, 64%; and squamous cell, 43%. Twenty-four patients (86%) completed all three cycles of cisplatin/pemetrexed. Of the 24 patients eligible for docetaxel, 21 (87%) received it. Grade 3/4 toxicities were neutropenia (39%), febrile neutropenia (14%), esophagitis (14%), and pneumonitis (4%). Median survival was 34 months, and 1-year survival was 66%. Survival was not significantly different in squamous and other histology patients. Tumor analysis in 16 patients showed that moderate/strong expression of thymidylate synthase was significantly associated with progression-free survival and overall survival.

CONCLUSION

Integrating pemetrexed in a concurrent therapy regimen for patients with stage III NSCLC is feasible and was associated with a median survival of 34 months.

Personalized medicine for lung cancer: new challenges for pathology

Recent advances in non-small-cell lung cancer (NSCLC) therapy mean the relatively simple discrimination between small-cell and 'non-small-cell' carcinoma is insufficient to determine the best treatment for individual patients. Safety, efficacy and prescribing requirements mandate more specific subtyping of NSCLC for several new drugs: practice made difficult by the tumour heterogeneity combined with the paucity of tissue in most diagnostic samples. Immunohistochemical approaches have emerged as accurate predictors of probable tumour histotype. P63 and/or cytokeratins 5 and 6 and thyroid transcription factor 1 (TTF1) are among the best predictors, respectively, of squamous and adenocarcinoma histology. Molecular characteristics may predict response to both newer molecular targeted agents and traditional cytotoxic agents. Specific mutations in the epidermal growth factor receptor (EGFR) gene as predictors of response to EGFR tyrosine kinase inhibitors (erlotinib, gefitinib) is the first example of markers which predict response to targeted agents. Actual drug targets [e.g. thymidilate synthase (TS) - pemetrexed] or markers of the tumour's ability to repair cytotoxic drug-induced damage [e.g. excision repair cross-complementation group 1 (ERCC1) - cisplatin] may well also complement NSCLC diagnosis. This extended diagnostic requirement from increasingly limited material provided by minimally invasive biopsy techniques poses major challenges for pathology.

An Evidence-Based Approach to the Use of Predictive Biomarkers in the Treatment of Non- Small Cell Lung Cancer (NSCLC)

Recent advances in the treatment of non-small cell lung cancer (NSCLC) have led to improvements in patient survival and quality of life. It is unclear whether molecular abnormalities associated with NSCLC cell survival, growth and proliferation are useful in predicting treatment benefit. We conducted a systematic review to establish which biomarkers contribute meaningfully to the management of NSCLC. A team of researchers searched PubMed and conference proceedings (ASCO, ESMO, IASLC, USCAP) using MESH terms for NSCLC and randomized trials (RCT), plus keywords for variables of interest. Evidence from multiple RCTs confirmed that histologic subtype is prognostic for survival and predictive of treatment efficacy and/or toxicity in NSCLC. Likewise, activating mutations of the epidermal growth factor receptor (EGFR) are associated with benefit from EGFR tyrosine kinase inhibitors in patients with advanced non-squamous NSCLC and should be assessed routinely. No biomarkers to date reliably predict response to anti-Vascular Endothelial Growth Factor (VEGF) therapies. There are inconsistent data on the role of ERCC1, BRCA, Beta tubulin III, RRM1, K-RAS, or TP-53 in treatment decisions. These tests should not be routinely used in selecting treatment at this time, whereas EML4/ALK translocations predict responses to specific targeted agents, the optimal assessment of this molecular abnormality has yet to be established. Personalized care of patients with NSCLC based on biomarkers is increasingly important to both clinical practice and research.

Thymidylate synthase inhibitors for non-small cell lung cancer

INTRODUCTION

The folate-dependent enzyme thymidylate synthase (TS) plays a pivotal role in DNA replication/repair and cancer cell proliferation, and represents a valid target for the treatment of several tumor types, including NSCLC. NSCLC is the leading cause of cancer-related mortality, and several TS inhibitors have gone into preclinical and clinical testing, with pemetrexed emerging for its approval and widespread use as first-/second-line and maintenance therapy for this disease.

AREAS COVERED

This review summarizes the therapeutic options in NSCLC, as well as the background and rationale for targeting TS. The authors also review recent pharmacogenetic studies and data from clinical trials evaluating novel TS inhibitors, hoping that the reader will gain a comprehensive overview of the field of TS inhibition, specifically relating to drugs used or being developed for lung cancer patients.

EXPERT OPINION

TS is a validated target in NSCLC. However, benefits from conventional chemotherapy in NSCLC have plateaued, and more cost-effective results should be obtained with individualized treatment. Accordingly, the clinical success for TS inhibitors may depend on our ability to correctly administer these agents following biomarker-driven patient selection, including TS genotype and expression, and using the right combination therapy.

Molecular classification of nonsmall cell lung cancer using a 4-protein quantitative assay

BACKGROUND

The importance of definitive histological subclassification has increased as drug trials have shown benefit associated with histology in nonsmall-cell lung cancer (NSCLC). The acuity of this problem is further exacerbated by the use of minimally invasive cytology samples. Here we describe the development and validation of a 4-protein classifier that differentiates primary lung adenocarcinomas (AC) from squamous cell carcinomas (SCC).

METHODS

Quantitative immunofluorescence (AQUA) was employed to measure proteins differentially expressed between AC and SCC followed by logistic regression analysis. An objective 4-protein classifier was generated to define likelihood of AC in a training set of 343 patients followed by validation in 2 independent cohorts (n = 197 and n = 235). The assay was then tested on 11 cytology specimens.

RESULTS

Statistical modeling selected thyroid transcription factor 1 (TTF1), CK5, CK13, and epidermal growth factor receptor (EGFR) to generate a weighted classifier and to identify the optimal cutpoint for differentiating AC from SCC. Using the pathologist's final diagnosis as the criterion standard, the molecular test showed a sensitivity of 96% and specificity of 93%. Blinded analysis of the validation sets yielded sensitivity and specificity of 96% and 97%, respectively. Our assay classified the cytology specimens with a specificity of 100% and sensitivity of 87.5%.

CONCLUSIONS

Molecular classification of NSCLC using an objective quantitative test can be highly accurate and could be translated into a diagnostic platform for broad clinical application.

Expression and pharmacological inhibition of thymidylate synthase and Src kinase in nonsmall cell lung cancer

The combination of cytotoxic chemotherapy with signaling pathway inhibitors represents a potential strategy to improve the treatment of nonsmall cell lung cancer (NSCLC). Thymidylate synthase (TS) is an enzyme essential for DNA synthesis, and its overexpression has been associated with the reduced sensitivity to antifolate agents. Src is a tyrosine kinase that modulates the cytotoxicity of cancer cells after drug treatment, and in vitro data indicate that its inhibition could revert the resistance to TS-inhibiting drugs. Our study investigated the significance of TS and Src expression in NSCLC tissues, and the effects of their pharmacological inhibition in cell lines. In tumor and normal tissues from 94 resected NSCLC patients, TS and Src transcript levels were found positively correlated (R(S) = 0.66), associated with patients smoking history and overall survival. At multivariate analysis, TS gene expression was an independent prognostic factor (relative risk (RR) = 1.78, from 1.16 to 2.72; p < 0.01). Immunohistochemical detection in tumor specimens confirmed that Src kinase activation, evaluated by phospho-specific antibody, was associated to a higher TS expression. In cell lines, dasatinib, a Src-inhibiting agent, synergistically enhanced pemetrexed-cytotoxicity of A549 cells, as evaluated by MTT and apoptosis assays. The biological explanation for this interaction was based on the upregulation of TS messenger RNA and protein levels induced by pemetrexed, which was significantly prevented by dasatinib cotreatment. The data of our study suggest that TS and Src may belong to a common pathway that bears prognostic significance in NSCLC, and that Src represents a potential target to improve the efficacy of TS-inhibiting agents.

Molecular predictors of response to chemotherapy in non-small cell lung cancer

Lung cancer is the leading cause of cancer-related mortality in the United States with 222,520 new cases and 157,300 deaths anticipated in 2010. The primary objective of any cancer treatment is to improve patient outcomes including overall survival and quality of life while minimizing treatment toxicity. As our knowledge of the molecular mechanisms involved in the pathogenesis of lung cancer evolves, improved methods of therapeutic selection may help clinicians better realize these goals. Such selection may be accomplished by examining biomarkers within patients' tumors that may provide prognostic information such as risk of recurrence in early stage disease or predict benefit from specific therapies regardless of disease stage. Three such biomarkers have emerged--excision repair cross-complementation group 1, the regulatory subunit of the ribonucleotide reductase enzyme, and thymidylate synthase--and are actively being evaluated in patients with non-small cell lung cancer. This review will focus on the role of these biomarkers as predictive and/or prognostic markers in the selection of chemotherapy regimens in non-small cell lung cancer patients.

Development of targeted therapy for squamous cell carcinomas of the head and neck

Targeted therapy is a very exciting era in the treatment of squamous cell carcinomas of the head and neck. After adding cetuximab to conventional chemotherapy and radiation therapy, we are strongly considering the role of induction chemotherapy with the addition of docetaxel. At the same time, other new treatments, especially targeted agents and novel combined regimens, are being evaluated in ongoing clinical trials. For example, several trials are attempting to combine docetaxel and cetuximab in chemoradiation or induction settings. However, in the near future we are likely to see a strong presence of targeted agents that have been found to be not only effective, but also less toxic than conventional chemotherapeutic agents. Their toxicity profiles make them eligible for addition to radiation treatment strategies, as well as other chemotherapy agents, or even for replacing these chemotherapy agents. In this article, we are going to review the indications and current role of cetuximab, tyrosine kinase inhibitors (gefitinib and erlotinib), dual inhibitors, IGF receptor inhibitors, as well as other agents that are in development for treatment of head and neck squamous cell carcinomas.

How close are we to customizing chemotherapy in early non-small cell lung cancer?

Although surgery is the only potentially curative treatment for early-stage non-small cell lung cancer (NSCLC), 5-year survival rates range from 77% for stage IA tumors to 23% in stage IIIA disease. Adjuvant chemotherapy has recently been established as a standard of care for resected stage II-III NSCLC, on the basis of large-scale clinical trials employing third-generation platinum-based regimens. As the overall absolute 5-year survival benefit from this approach does not exceed 5% and potential long-term complications are an issue of concern, the aim of customized adjuvant systemic treatment is to optimize the toxicity/benefit ratio, so that low-risk individuals are spared from unnecessary intervention, while avoiding undertreatment of high-risk patients, including those with stage I disease. Therefore, the application of reliable prognostic and predictive biomarkers would enable to identify appropriate patients for the most effective treatment.This is an overview of the data available on the most promising clinicopathological and molecular biomarkers that could affect adjuvant and neoadjuvant chemotherapy decisions for operable NSCLC in routine practice. Among the numerous candidate molecular biomarkers, only few gene-expression profiling signatures provide clinically relevant information warranting further validation. On the other hand, real-time quantitative polymerase-chain reaction strategy involving relatively small number of genes offers a practical alternative, with high cross-platform performance. Although data extrapolation from the metastatic setting should be cautious, the concept of personalized, pharmacogenomics-guided chemotherapy for early NSCLC seems feasible, and is currently being evaluated in randomized phase 2 and 3 trials. The mRNA and/or protein expression levels of excision repair cross-complementation group 1, ribonucleotide reductase M1 and breast cancer susceptibility gene 1 are among the most potential biomarkers for early disease, with stage-independent prognostic and predictive values, the clinical utility of which is being validated prospectively. Inter-assay discordance in determining the biomarker status and association with clinical outcomes is noteworthing.

Emerging treatment options in the management of non-small cell lung cancer

Lung cancer (LC) has become the leading cancer-related cause of death in the US and in developed European countries in the last decade. Its incidence is still growing in females and in smokers. Surgery remains the treatment of choice whenever feasible, but unfortunately, many patients have an advanced LC at presentation and one-third of potentially operable patients do not receive a tumor resection because of their low compliance for intervention due to their compromised cardiopulmonary functions and other comorbidities. For these patients the alternative therapeutic options are stereotactic radiotherapy or percutaneous radiofrequency. When surgery is planned, an anatomical resection (segmentectomy, lobectomy, bilobectomy, pneumonectomy, sleeve lobectomy) is usually performed; wedge resection (considered as a nonanatomical one) is generally the accepted option for unfit patients. The recent increase in discovering small and peripheral LCs and/or ground-glass opacities with screening programs has dramatically increased surgeons' interest in limited resections. The role of these resections is discussed. Also, recent improvements in molecular biology techniques have increased the chemotherapic options for neoadjuvant LC treatment. The role and the importance of targeted chemotherapy is also discussed.

Biomarkers, prediction, and prognosis in non-small-cell lung cancer: a platform for personalized treatment

In lung cancer, the introduction of targeted agents in those patients who carry a genetic abnormality has resulted in better clinical outcomes with better quality of life. These molecular abnormalities have also become predictive biomarkers. It is imperative that we continue searching for these biomarkers in different tumorigenesis pathways, so we can provide the most appropriate therapy to each individual in the near future. Since the 1980s, chemotherapy for patients with advanced non-small-cell lung cancer has been shown to provide a small improvement in survival. In the early 1990s, platinum-based regimens became the backbone of treatment for this disease. In 2002, the Eastern Cooperative Oncology Group 1594 clinical trial showed that there was no overall survival difference among four common chemotherapy regimens used in non-small-cell lung cancer. It was not until 2006 when the introduction of biologic agents into the field of lung cancer improved, for the first time ever, median overall survival beyond 1 year. To date, we recognize that there are differences between all histologic subtypes of non-small-cell lung cancer in terms of their response to specific agents. All these plus the introduction of molecular medicine have resulted in the identification of markers for prognosis and prediction in lung cancer. In this review, we describe the actual and ongoing clinical efforts to validate the prognostic and predictive value of these potential markers in lung cancer. We hope that the clinical use of biomarkers will help us to deliver personalized medicine to our lung cancer patients by improving their quality of response which may translate into further survival advantage.

A systematic review of the interobserver variability for histology in the differentiation between squamous and nonsquamous non-small cell lung cancer

INTRODUCTION

The importance of identifying non-small cell lung cancer (NSCLC) histologic subtype has increased recently because of the development of target-specific chemotherapeutic agents. This systematic review was undertaken to examine the interobserver variability for histology in differentiating between subtypes of NSCLC, specifically the ability to differentiate squamous from nonsquamous histology.

METHODS

A systematic literature search was undertaken to identify studies that evaluated the reproducibility of histologic diagnosis by pathologists in their reporting of NSCLC subtypes. Studies were screened using a priori defined eligibility criteria. The National Health and Medical Research Council diagnostic levels of evidence were applied and quality assessed using the Quality Assessment of Diagnostic Accuracy Studies tool. Data were extracted and reanalyzed to permit comparison of agreement in nonsquamous and squamous cell carcinoma by 2 × 2 tables. Percentage agreement and kappa statistics were calculated for each included study.

RESULTS

Out of 1480 articles identified through the literature search, six were eligible for inclusion. The percentage agreement for all subtypes of NSCLC in the included studies ranged from 67.1 to 89.6% (κ, 0.42-0.84). Based on the primary reanalysis of data (reanalysis 1), agreement between pathologists in differentiating nonsquamous and squamous histology ranged from 77.0 to 94.2% (κ = 0.48-0.88) indicating a moderate to high level of agreement.

CONCLUSION

The reasonably high agreement and kappa statistics for the included studies suggest that pathologists can reproducibly differentiate between nonsquamous and squamous NSCLC. This is clinically important in guiding oncologist decision making in choosing the most appropriate therapy for their patients.

Treatment-by-histology interaction analyses in three phase III trials show superiority of pemetrexed in nonsquamous non-small cell lung cancer

INTRODUCTION

Recently, histology has emerged as a predictive factor for pemetrexed efficacy in non-small cell lung cancer (NSCLC). These analyses evaluate whether the differential efficacy of pemetrexed by NSCLC histology is reproducible and consistent across three registration studies of different lines of therapy (first-line/second-line and maintenance settings).

METHODS

The reported studies for patients with advanced NSCLC were pemetrexed versus docetaxel in previously treated patients (N = 571), cisplatin plus pemetrexed versus cisplatin plus gemcitabine in chemotherapy-naive patients (N = 1725), and maintenance pemetrexed plus best supportive care versus placebo plus best supportive care (N = 663). Cox models of overall survival (OS) and progression-free survival (PFS) were used to test for a significant treatment-by-histology interaction (THI). A significant THI indicates that the efficacy benefit for pemetrexed relative to the control arm is greater in patients with nonsquamous histology than in those with squamous histology. Subsequent Cox models were used to estimate hazard ratios for OS and PFS according to histology.

RESULTS

Histology was well balanced between treatment arms in each study. Across all three studies, no clinically relevant differences were observed for the safety profile of pemetrexed among histologic groups. THIs were statistically significant in all three studies for OS (p = 0.001, 0.002, and 0.033, respectively) and PFS (p = 0.004, 0.002, and 0.036, respectively).

CONCLUSIONS

These analyses demonstrate a statistically significant interaction between treatment effect and NSCLC histology, indicating superior efficacy of pemetrexed in nonsquamous patients compared with other standard treatment options. Thus, histology is consistently predictive of the improved efficacy of pemetrexed in patients with nonsquamous NSCLC.

Personalized medicine for non-small-cell lung cancer

Non-small-cell lung cancer (NSCLC) is a heterogeneous illness associated with a high mortality rate. Personalized therapy may improve treatment outcomes by identification of a specific genotypic anomaly and target-specific therapy. The most significant development in recent years was the discovery of activated EGF receptor (EGFR) mutations at exons 19 and 21. Patients with EGFR mutations respond dramatically to EGFR tyrosine kinase inhibitors such as gefitinib or erlotinib, resulting in longer progression-free survival. Multiple randomized studies, including the Iressa Pan-Asia Study and WJTOG3405, have confirmed the role of EGFR tyrosine kinase inhibitors as standard first-line therapy for patients with the EGFR mutation. In this article, we summarize the current nonpersonalized therapies and examine the available and investigational personalized therapies for patients with resectable early-stage, unresectable locally advanced, or metastatic disease.

Thymidylate synthase as a determinant of pemetrexed sensitivity in non-small cell lung cancer

Background:

Although a high level of thymidylate synthase (TS) expression in malignant tumours has been suggested to be related to a reduced sensitivity to the antifolate drug pemetrexed, no direct evidence for such an association has been demonstrated in non-small cell lung cancer (NSCLC). We have now investigated the effect of TS overexpression on pemetrexed sensitivity in NSCLC cells.

Methods:

We established NSCLC cell lines that stably overexpress TS and examined the effects of such overexpression on the cytotoxicity of pemetrexed both in vitro and in xenograft models. We further examined the relation between TS expression in tumour specimens from NSCLC patients and the tumour response to pemetrexed by immunohistochemical analysis.

Results:

The sensitivity of NSCLC cells overexpressing TS to the antiproliferative effect of pemetrexed was markedly reduced compared with that of control cells. The inhibition of DNA synthesis and induction of apoptosis by pemetrexed were also greatly attenuated by forced expression of TS. Furthermore, tumours formed by TS-overexpressing NSCLC cells in nude mice were resistant to the growth-inhibitory effect of pemetrexed observed with control tumours. Finally, the level of TS expression in tumours of non-responding patients was significantly higher than that in those of responders, suggestive of an inverse correlation between TS expression and tumour response to pemetrexed.

Conclusion:

A high level of TS expression confers a reduced sensitivity to pemetrexed. TS expression is thus a potential predictive marker for response to pemetrexed-based chemotherapy in NSCLC patients.

Biomarkers of DNA repair and related pathways: significance in non-small cell lung cancer

PURPOSE OF REVIEW

To review selected biomarkers of DNA repair and related pathways as they relate to the management of patients with non-small cell lung cancer (NSCLC), emphasizing the role of individualized, chemotherapy for advanced disease, and discussing potential applications in early disease.

RECENT FINDINGS

The activity of molecular-targeted agents in NSCLC patients whose tumor possesses relevant biomarkers [such as epidermal growth factor receptor (EGFR) activating mutations and ALK translocations] has made personalized therapy possible. In addition, preclinical and clinical studies have shown that histopathological and biomolecular factors can correlate with clinical outcome in patients with NSCLC treated with chemotherapy. As a result, tumor histology is now routinely considered in selecting chemotherapy for NSCLC patients, such as pemetrexed for nonsquamous histology. Molecular tumor and host factors, including genes involved in DNA-repair and synthesis, are potentially even more relevant as predictive biomarkers of tumor response to chemotherapy. However, individual molecular markers and gene signatures need further validation and standardization, before routine use in the clinic can be recommended.

SUMMARY

In the era of molecular-targeted agents, individualized therapy based on molecular biomarkers has become a reality in the treatment of patients with advanced NSCLC. Further studies are needed to optimize current treatment algorithms with regard to biomarkers for chemotherapy benefit, to refine molecular markers, and to translate these findings to early stage NSCLC.

Thymidylate synthase (TS) gene expression in primary lung cancer patients: a large-scale study in Japanese population

BACKGROUND

Previous small-sized studies showed lower thymidylate synthase (TS) expression in adenocarcinoma of the lung, which may explain higher antitumor activity of TS-inhibiting agents such as pemetrexed.

PATIENTS AND METHODS

To quantitatively measure TS gene expression in a large-scale Japanese population (n = 2621) with primary lung cancer, laser-captured microdissected sections were cut from primary tumors, surrounding normal lung tissues and involved nodes.

RESULTS

TS gene expression level in primary tumor was significantly higher than that in normal lung tissue (mean TS/β-actin, 3.4 and 1.0, respectively; P < 0.01), and TS gene expression level was further higher in involved node (mean TS/β-actin, 7.7; P < 0.01). Analyses of TS gene expression levels in primary tumor according to histologic cell type revealed that small-cell carcinoma showed highest TS expression (mean TS/β-actin, 13.8) and that squamous cell carcinoma showed higher TS expression as compared with adenocarcinoma (mean TS/β-actin, 4.3 and 2.3, respectively; P < 0.01); TS gene expression was significantly increased along with a decrease in the grade of tumor cell differentiation. There was no significant difference in TS gene expression according to any other patient characteristics including tumor progression.

CONCLUSION

Lower TS expression in adenocarcinoma of the lung was confirmed in a large-scale study.

Low thymidylate synthase, thymidine phosphorylase, and dihydropyrimidine dehydrogenase mRNA expression correlate with prolonged survival in resected non-small-cell lung cancer

BACKGROUND

Thymidylate synthase (TS), thymidine phosphorylase (TP), and dihydropyrimidine dehydrogenase (DPD) are key enzymes in the 5-fluorouracil (5-FU) pathway. The aim of this study was to investigate the mRNA expression of TS, TP, and DPD in tumor and nontumor lung tissue of patients with NSCLC and to determine the potential of these genes as molecular biomarkers.

MATERIALS AND METHODS

The TS, TP, and DPD mRNA expression was analyzed in tumor and nontumor tissue of 91 patients with NSCLC by quantitative real-time reverse-transcriptase polymerase chain reaction (RT-PCR) with β-actin as the internal control. All tumors were R0 resected. The median follow-up was 85.9 months.

RESULTS

The mRNA expression of TS, TP, and DPD was detectable in both tumor and nontumor tissue. Tumor TP (tTP) seems to correlate with tumor TS (tTS) and tumor DPD (tDPD) mRNA expression, but no correlation in the mRNA expression of tTS and tDPD was found. The TS and TP mRNA expression levels were significantly associated with patient prognosis. The 5-year survival probability was 58.7% (TS), and 59.6% (TP) for patients with a low TS and TP mRNA expression and 33.4% (TS), and 31.8% (TP) for patients with a high mRNA expression (P = .04 [TS]; P = .03 [TP]; log-rank). The probability of survival was significantly different among patients with no and any 1 highly expressed gene compared with patients with any 2 or more of the 3 investigated genes highly expressed (P = .012).

CONCLUSION

High TS, TP, and DPD mRNA expression are biomarkers for a more severe malign NSCLC biology. Quantitation of the mRNA expression of these genes seems to be helpful in differing patients with unequal malign tumor entities and therefore possibly helpful in selecting tailored additional therapies to control the disease.

Safety and resource utilization by non-small cell lung cancer histology: results from the randomized phase III study of pemetrexed plus cisplatin versus gemcitabine plus cisplatin in chemonaïve patients with advanced non-small cell lung cancer

INTRODUCTION

A prespecified analysis of the large, randomized, phase III study in advanced non-small cell lung cancer showed significant improvement in survival for nonsquamous patients treated with pemetrexed/cisplatin versus gemcitabine/cisplatin. Selected grade 3/4 toxicities and resource utilization favored pemetrexed in the overall population, but detailed safety results by histology have not been reported.

METHODS

Treated patients were included in this analysis of safety by histology. At each cycle, adverse events were assessed, and concomitant medications, transfusions, and hospitalizations were recorded. Measures were summarized by histology and compared between arms with Fisher's exact test.

RESULTS

When analyzed by squamous and nonsquamous histology, safety and resource utilization for each treatment arm paralleled those of the overall population. Selected toxicities did not vary by histology. Concomitant medication use and hospitalizations were also very similar to the patterns observed in the overall population.

CONCLUSIONS

Although previous efficacy analyses showed a significant pemetrexed treatment advantage for nonsquamous patients, results of this analysis indicate that safety and resource utilization do not vary by histology and are consistent with the overall population. The safety and resource utilization of patients treated with pemetrexed/cisplatin are predictable, reproducible, and consistent with the established favorable safety profile of pemetrexed, regardless of histology.

Prognostic impact of node involvement pattern in pN1 non-small cell lung cancer patients

INTRODUCTION

We previously showed that squamous cell carcinoma (SCC) patients with directly involved N1 nodes resulted in outcomes significantly better than those with separately involved N1 nodes. The purpose of this study was to evaluate the prognostic effect of node involvement patterns in pN1 non-small cell lung cancer (NSCLC) patients, with special attention given to any differences between SCC and adenocarcinoma (AD).

METHODS

We reviewed 324 consecutive patients with completely resected pN1 NSCLC and classified them into two groups based on their node involvement patterns: directly or separately involved N1 groups. To compare survival rates, 1545 pN0 patients and 330 pN2 patients were also investigated.

RESULTS

Univariate and multivariate analyses showed that the node involvement pattern was significantly associated with pN1 NSCLC patient outcome. The directly involved N1 group had a much better 5-year overall survival rate of 60.1% compared with 45.0% for the separately involved N1 group. In SCC patients, the directly involved N1 group showed an overall survival similar to pN0 patients, whereas overall survival of the separately involved N1 group was identical to that of pN2 patients, and their survival rates were significantly different. In AD patients, however, the survival rates were marginally different between the directly and separately involved N1 groups, and they were intermediate between pN0 and pN2 patient survival rates.

CONCLUSIONS

Node involvement patterns had significant prognostic effect in pN1 NSCLC patients. This effect was different between SCC and AD cases. The subclassification of N1 based on node involvement pattern is of significance for SCC patients but not for AD patients.

Pemetrexed in advanced non-small cell lung cancer

INTRODUCTION

For patients with advanced NSCLC, treatment outcomes are still disappointing and the search for new active and safe drugs is warranted. The chemotherapeutic agent pemetrexed has produced, in the last years, an innovation of therapeutic algorithms of this disease, and this review is aimed at describing the role of pemetrexed in the treatment of NSCLC.

AREAS COVERED

In the present review, we discuss the mechanism of action of pemetrexed, its safety profile and the main clinical data on pemetrexed in NSCLC treatment. The reader will gain information on pemetrexed efficacy in the first-line, second-line and maintenance treatment of advanced NSCLC. Moreover, the histotype-based approach to NSCLC treatment, which is important for the selection of patients to be treated with pemetrexed, is clarified.

EXPERT OPINION

The recent introduction of pemetrexed in the first-line and maintenance treatment of advanced non-squamous NSCLC represents, in our opinion, a significant step forward in the treatment of this disease in the last 3 years. Furthermore, cisplatin plus pemetrexed has a more favorable safety profile as compared with those of pre-existing cisplatin-based regimens.

EGFR mutation: Significance as a stratification factor in the era of molecular-targeted therapy

Somatic mutations of epidermal growth factor receptor (EGFR) are the strongest predictive markers for the response to EGFR-tyrosine kinase inhibitors (TKIs). Patients with EGFR mutations generally receive EGFR-TKI treatment, and their survival has been significantly improved compared with that before the development of EGFR-TKIs. This study aimed to clarify the impact of EGFR mutational status on the survival of patients with non-small cell lung cancer (NSCLC) receiving cytotoxic agents, but not EGFR-TKIs, as their first-line chemotherapy. In addition, we analyzed patients with EGFR mutations to determine whether the timing of EGFR-TKI administration affects overall survival (OS). A total of 83 NSCLC patients with stage IIIB/IV who received chemotherapy alone and whose EGFR mutational status was known were investigated. Univariate and multivariate analysis for OS was performed using parameters such as age, gender, performance status (PS), histology, disease stage, smoking status, EGFR mutational status and administration of a first-line regimen. Among the 52 patients with EGFR mutations who received EGFR-TKIs, OS between those who received EGFR-TKIs as their first-line treatment and after chemotherapy were similar. Among the 83 patients who received cytotoxic agents as their first-line chemotherapy, the multivariate analysis showed OS to be significantly associated with PS (p<0.001), histology (p=0.039) and EGFR mutational status (p=0.040). OS was almost similar among the 52 patients with EGFR mutations who received EGFR-TKIs in a first- and second-line setting (25.6 vs. 26.8 months, p=0.914). The EGFR mutational status had a significant impact on the survival of NSCLC patients, although these patients did not receive EGFR-TKIs as their first-line chemotherapy. In future randomized trials, even when EGFR-TKIs are not included in experimental regimens, patients may need to be stratified by EGFR mutational status in order that study results be evaluated appropriately.