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

Downregulation of both EGFR and ErbB3 improves the cellular response to pemetrexed in an established pemetrexed‑resistant lung adenocarcinoma A549 cell line

Epidermal growth factor receptor (EGFR) and ErbB3 (HER3) play important roles in the regulation of cell proliferation, differentiation, anti-apoptosis and chemoresistance; however, their dysregulation in pemetrexed (PEM) resistance remains unclear. The aim of the present study was to clarify the relationship between PEM resistance and gene expression of EGFR and ErbB3, by establishing the PEM-resistant lung adenocarcinoma A549 cell line, A549/PEM. Compared with A549 cells, the A549/PEM cells were significantly more resistant to PEM (P=0.0024). The downregulation of S phase and arrest at G1 stage were detected in the A549/PEM cell line when compared to the A549 cells (P<0.05). The apoptosis rate of A549/PEM cells was much lower than that of the A549 cells after a 24 h continuous exposure to PEM (P<0.001). Real-time PCR and western blotting demonstrated the overexpression of EGFR and ErbB3 in A549/PEM cells. However, downregulation of EGFR or ErbB3 by lentiviral delivered shRNAs in A549/PEM cells showed no significant correlation with PEM sensitivity while silencing both EGFR and ErbB3 increased the cellular response to PEM in the A549/PEM cells and significantly decreased phosphorylation of STAT3, AKT and ERK. Together, these data suggest that either high expression of EGFR or ErbB3 plays a critical role in the cellular response to PEM in human lung adenocarcinoma cells though EGFR/ErbB3-dependent pathways.

Thymidylate synthase expression and outcome of patients receiving pemetrexed for advanced nonsquamous non-small-cell lung cancer in a prospective blinded assessment phase II clinical trial

INTRODUCTION

In retrospective analyses of patients with nonsquamous non-small-cell lung cancer treated with pemetrexed, low thymidylate synthase (TS) expression is associated with better clinical outcomes. This phase II study explored this association prospectively at the protein and mRNA-expression level.

METHODS

Treatment-naive patients with nonsquamous non-small-cell lung cancer (stage IIIB/IV) had four cycles of first-line chemotherapy with pemetrexed/cisplatin. Nonprogressing patients continued on pemetrexed maintenance until progression or maximum tolerability. TS expression (nucleus/cytoplasm/total) was assessed in diagnostic tissue samples by immunohistochemistry (IHC; H-scores), and quantitative reverse-transcriptase polymerase chain reaction. Cox regression was used to assess the association between H-scores and progression-free/overall survival (PFS/OS) distribution estimated by the Kaplan-Meier method. Maximal χ² analysis identified optimal cutpoints between low TS- and high TS-expression groups, yielding maximal associations with PFS/OS.

RESULTS

The study enrolled 70 patients; of these 43 (61.4%) started maintenance treatment. In 60 patients with valid H-scores, median (m) PFS was 5.5 (95% confidence interval [CI], 3.9-6.9) months, mOS was 9.6 (95% CI, 7.3-15.7) months. Higher nuclear TS expression was significantly associated with shorter PFS and OS (primary analysis IHC, PFS: p < 0.0001; hazard ratio per 1-unit increase: 1.015; 95%CI, 1.008-1.021). At the optimal cutpoint of nuclear H-score (70), mPFS in the low TS- versus high TS-expression groups was 7.1 (5.7-8.3) versus 2.6 (1.3-4.1) months (p = 0.0015; hazard ratio = 0.28; 95%CI, 0.16-0.52; n = 40/20). Trends were similar for cytoplasm H-scores, quantitative reverse-transcriptase polymerase chain reaction and other clinical endpoints (OS, response, and disease control).

CONCLUSIONS

The primary endpoint was met; low TS expression was associated with longer PFS. Further randomized studies are needed to explore nuclear TS IHC expression as a potential biomarker of clinical outcomes for pemetrexed treatment in larger patient cohorts.

Thymidylate Synthase as a Predictive Biomarker for Pemetrexed Response in NSCLC

In recent years, major strides in cancer research have made it possible to select personalized chemotherapy recommendations based on an individual patient's tumor biology. The prognostic and/or predictive ability of biomarkers seeks to tailor the use of targeted chemotherapy and can result in improved clinical outcomes with reduced toxicity. A proliferation of new technology and pharmacotherapeutics in the setting of current FDA Clinical Laboratory Improvement Amendment (CLIA) standards has resulted in a recent surge in direct-to-physician biomarker tests. However, in the absence of clinical validation, there is the concern that the biomarkers may be utilized prematurely, resulting in improper chemotherapy selection and patient harm. Thymidylate synthase (TS) has been marketed as a predictive biomarker for the use of pemetrexed in NSCLC. We will examine the evidence behind the use of TS as a predictive biomarker to predict response to pemetrexed in NSCLC. At this time, the evidence does not currently support using TS assays to guide chemotherapy selection outside of a clinical research protocol.

Prognostic and predictive markers for personalized adjuvant therapy for non-small-cell lung cancer patients

Adjuvant chemotherapy following surgical resection in non-small-cell lung cancer patients with large tumors (>4 cm) or tumors with lymph node metastases has emerged as a standard of care. The benefits of adjuvant chemotherapy are modest, with a 5-year survival improvement of only 5–10%. In addition, survival rates of 25% or greater with surgery alone suggest that some patients do not need adjuvant therapy. Therefore, there is a need to develop prognostic and predictive markers to identify patients in need of adjuvant therapy and the patients likely to benefit from such therapy. Many factors have been evaluated for this purpose and some of these factors, such as visceral pleural invasion, can influence the decision to use adjuvant chemotherapy. However, most of the available data are retrospective, which limits the utility of these markers in current practice. Ongoing trials are evaluating many promising markers and may guide adjuvant therapy in the future.

¹⁸F-FDG uptake on PET is a predictive marker of thymidylate synthase expression in patients with thoracic neoplasms

The aim of this study was to investigate the relationship between the expression levels of thymidylate synthase (TS) and 2-[¹⁸F]-fluoro-2-deoxy-D-glucose (¹⁸F-FDG) uptake on positron emission tomography (PET) in various thoracic neoplasms. In total, 392 patients [non-small cell lung cancer (NSCLC) (n=140), malignant pleural mesothelioma (MPM) (n=21), pulmonary metastatic tumors (PMT) (n=148), thymic epithelial tumors (n=49) and pulmonary neuroendocrine (NE) tumor (n=34)] who underwent ¹⁸F-FDG PET before treatment were included in this study. Tumor sections were stained using immunohistochemistry for determination of TS, orotate phosphoribosyltransferase (OPRT), dihydropyrimidine dehydrogenase (DPD), vascular endothelial growth factor (VEGF), microvessel density (MVD), CD34 and p53. The expression of TS in thoracic neoplasms had a positivity of 58% (230/392), and the positive rates of TS expression in NSCLC, PMT, thymic epithelial tumor, NE tumor and MPM samples were 56, 57, 57, 85 and 47%, respectively. The positivity of TS expression was significantly higher in NE tumors compared to that in other thoracic tumors. A statistically significant correlation between TS expression and ¹⁸F-FDG uptake was observed in thoracic neoplasms, in particular primary lung adenocarcinomas, high-grade NE tumors, thymomas and MPMs. Moreover, TS expression was closely associated with angiogenesis, DPD, OPRT and p53. Our results indicated that SUV(max) by ¹⁸F-FDG uptake may be an alternative biomarker for predicting TS expression in patients with primary lung adenocarcinoma, high-grade NE tumor, thymoma and MPM.

New targets in non-small cell lung cancer

Lung cancer remains the most common cause of cancer-related death in the United States. At presentation, the majority of patients have regional or systemic metastases and therefore require systemic therapy. For years, chemotherapy was the only systemic therapy option. A major paradigm shift has occurred in recent years with the identification of driver genetic alterations in some non-small cell lung cancers (NSCLCs). It is part of current standard of care to assess epidermal growth factor receptor (EGFR) mutations and anaplastic lymphoma kinase (ALK) translocations in tumors of patients with advanced NSCLC. Drugs targeting these mutations provide significant clinical benefit and are the preferred therapeutic option in these patients. Ongoing clinical trials are assessing the clinical benefit from targeting other driver genetic alterations. Further therapeutic targets have been identified through greater understanding of the variety of molecular processes that facilitate tumor formation and progression. Some of these new therapeutic targets are heat shock proteins and targets that can allow enhanced anti-tumor immune response. It is expected that these advances will allow personalized management of NSCLC patients and move us away from approaching all NSCLC patients with the same therapeutic tools.

Synergistic effects of pemetrexed and amrubicin in non-small cell lung cancer cell lines: Potential for combination therapy

The purpose is to examine the synergistic effect of pemetrexed (PEM) and amrubicin (AMR) on the proliferation of lung cancer cell lines. In vitro, dose-dependent synergistic effects of concurrent PEM and AMRol, which is an active metabolite of AMR were observed in A549 and H460 cells. In real-time RT-qPCR analysis and western blotting, expression of the target enzymes of PEM were suppressed in cells treated with amrubicinol alone. In vivo, AMR/PEM treatment also showed synergistic antitumor activity both in A549-bearing and H520-bearing mice. PEM and AMR work synergistically to inhibit the proliferation of several different lung cancer cell lines.

Chemotherapy advances in small-cell lung cancer

Although chemotherapeutic advances have recently been heralded in lung adenocarcinomas, such success with small-cell lung cancer (SCLC) has been ominously absent. Indeed, the dismal outlook of this disease is exemplified by the failure of any significant advances in first line therapy since the introduction of the current standard platinum-etoposide doublet over 30 years ago. Moreover, such sluggish progress is compounded by the dearth of FDA-approved agents for patients with relapsed disease. However, over the past decade, novel formulations of drug classes commonly used in SCLC (e.g. topoisomerase inhibitors, anthracyclines, alkylating and platinum agents) are emerging as potential alternatives that could effectively add to the armamentarium of agents currently at our disposal. This review is introduced with an overview on the historical development of chemotherapeutic regimens used in this disease and followed by the recent encouraging advances witnessed in clinical trials with drugs such as amrubicin and belotecan which are forging new horizons for future treatment algorithms.

Thymidylate synthase and folyl-polyglutamate synthase are not clinically useful markers of response to pemetrexed in patients with malignant pleural mesothelioma

PURPOSE

Thymidylate synthase (TS) is a potential predictor of outcome after pemetrexed (Pem) in patients with malignant pleural mesothelioma (MPM), and assays measuring TS levels are commercially marketed. The goal of this study was to further evaluate the value of TS and to study another potential biomarker of response, the enzyme, folyl-polyglutamate synthase (FPGS), which activates Pem intracellularly.

METHODS

Levels of TS and FPGS were semi-quantitatively determined immunohistochemically using H-scores on tissue samples from 85 MPM patients receiving Pem as primary therapy. H-score was correlated with radiographic disease control rate (DCR), time to progression (TTP) and overall survival (OS). In addition, expression levels of TS and FPGS in MPM cell lines were determined using immunoblotting and correlated with their sensitivity to Pem-induced cell death.

RESULTS

H-scores from patients with disease control versus progressive disease showed extensive overlap. There were no significant correlations of DCR, TTP, or OS to either TS levels (p = 0.73, 0.93, and 0.59, respectively), FPGS levels (p = 0.95, 0.77, and 0.43, respectively) or the ratio of FPGS/TS using the median scores of each test as cutoffs. There was no correlation between TS or FPGS expression and chemosensitivity of mesothelioma cells to Pem in vitro.

CONCLUSIONS

Although previous retrospective data suggest that TS and FPGS expression might be potential markers of Pem efficacy in MPM, our data indicate these markers lack sufficient predictive value in individual patients and should not be used to guide therapeutic decisions in the absence of prospective studies.

Association between TYMS expression and efficacy of pemetrexed-based chemotherapy in advanced non-small cell lung cancer: a meta-analysis

Background

The predictive value of thymidylate synthase (TYMS) to sensitivity to pemetrexed-based chemotherapy in advanced non-small cell lung cancer (NSCLC) patients is controversial. We conducted a meta-analysis of all relevant published data to assess the association of TYMS expression with the clinical outcomes of pemetrexed-based regimen in advanced NSCLC.

Patients and Methods

We conducted an electronic search using using PubMed, Embase, OVID and Cochrane Library databases and manual search. Pooled odds ratio (OR) for the response rate and hazard ratio (HR) for the overall survival and progression free survival were calculated using the software Revman 5.0.

Results

There were 11 studies (n=798) met our criteria for evaluation. Response rate to pemetrexed-based regimen was significantly higher in patients with low/negative TYMS (OR=2.96, 95%CI [1.81, 4.86] P<0.0001). Patients with low/negative TYMS who were treated with pemetrexed-based regimen had longer progression free survival (HR 0.50, 95%CI [0.41, 0.61] P <0.00001) and overall survival (HR 0.41, 95%CI [0.22, 0.78] P=0.007) than those with high/positive TYMS.

Conclusions

Low/negative TYMS expression was significantly associated with higher response rate, longer median survival and longer progression free survival for advanced NSCLC patients receiving pemtrexed-based chemotherapy. Hence, TYMS may be a potential predictor of sensitivity to pemtrexed-based chemotherapy in advanced NSCLC. Large scale prospective clinical trials are still warranted.

Management of non-small-cell lung cancer: recent developments

Non-small-cell lung cancer is one of the leading causes of deaths from cancer worldwide. Therefore, improvements in diagnostics and treatments are urgently needed. In this review, we will discuss the evolution of lung cancer staging towards more non-invasive, endoscopy-based, and image-based methods, and the development of stage-adapted treatment. A special focus will be placed on the role of novel surgical approaches and modern radiotherapy strategies for early stages of disease, the effect of multimodal treatment in locally advanced disease, and ongoing developments in the treatment of patients with metastatic disease. In particular, we will include an emphasis on targeted therapies, which are based on the assumption that a treatable driver mutation or gene rearrangement is present within the tumour. Finally, the position of lung cancer treatment on the pathway to personalised therapy will be discussed.

Genetic alterations defining NSCLC subtypes and their therapeutic implications

Lung cancer is the leading cause of cancer death worldwide, accounting for more deaths than breast, prostate and colon cancer combined. While treatment decisions are determined primarily by stage, therapeutically non small cell lung cancer (NSCLC) has traditionally been treated as a single disease. However, recent findings have led to the recognition of histology and molecular subtypes as important determinants in treatment selection. Identifying the genetic differences that define these molecular and histological subtypes has the potential to impact treatment and as such is currently the focus of much research. Microarray and genomic sequencing efforts have provided unparalleled insight into the genomes of lung cancer subtypes, specifically adenocarcinoma (AC) and squamous cell carcinoma (SqCC), revealing subtype specific genomic alterations and molecular subtypes as well as differences in cell signaling pathways. In this review, we discuss the recurrent genomic alterations characteristic of AC and SqCC (including molecular subtypes), their therapeutic implications and emerging clinical practices aimed at tailoring treatments based on a tumor's molecular alterations with the hope of improving patient response and survival.

Clinical benefit from pemetrexed before and after crizotinib exposure and from crizotinib before and after pemetrexed exposure in patients with anaplastic lymphoma kinase-positive non-small-cell lung cancer

BACKGROUND

Crizotinib produces high response rates and prolonged PFS in ALK+ NSCLC. Retrospective analyses suggest enhanced sensitivity to pemetrexed in crizotinib naive ALK+ NSCLC. Cross-resistance between crizotinib and pemetrexed has not been previously investigated.

PATIENTS AND METHODS

Patients with stage IV ALK+ NSCLC treated with PEM-CRIZ, or CRIZ-PEM were identified. Overall PFS and PFS excluding central nervous system events (eCNS) were compared.

RESULTS

Objective response rates in evaluable patients were 66% (PEM-CRIZ) and 75% (CRIZ-PEM) for pemetrexed and 84% (CRIZ-PEM) and 66% (PEM-CRIZ) for crizotinib. For PEM-CRIZ (n = 29), median PFS and eCNS PFS were both 6 months with pemetrexed, and 10 and 14.5 months, respectively, with crizotinib. For CRIZ-PEM (n = 9), median PFS and eCNS PFS were 4.5 and 3 months, respectively, with pemetrexed, and 8.5 and 7.5 months, respectively, with crizotinib. There was a statistically significant increase in the risk of an overall PFS event with pemetrexed when administered after crizotinib (P = .0277; hazard ratio [HR], 2.5898; 95% confidence interval [CI], 1.1100-6.0424), but differences in the risk of an eCNS PFS event were not significant (P = 0.4913; HR, 1.3521; 95% CI, 0.5727-3.1920). Neither overall nor eCNS PFS for patients while taking crizotinib was associated with a sequence effect relative to pemetrexed.

CONCLUSION

Crizotinib and pemetrexed are active drugs in ALK+ NSCLC. PFS benefit appeared higher with crizotinib than with pemetrexed. PFS benefit from pemetrexed was less after crizotinib compared with before crizotinib, however, this difference was only statistically significant for overall and not eCNS PFS. Pemetrexed exposure did not seem to affect crizotinib outcomes.

Exploratory study on the correlation between 14 lung cancer-related gene expression and specific clinical characteristics of NSCLC patients

Personalized medicine has become essential in the treatment of lung cancer. However, the lung cancer-related gene expression profiles in non-small cell lung cancer (NSCLC) patients have not been elucidated. In this study, the correlation between gene expression profiles and clinicopathological characteristics was investigated in NSCLC patients. A total of 95 patients were enrolled in this study. The mRNA expression levels of 14 genes were assessed by multiplex branched DNA liquidchip (MBL) technology and data on 9 clinicopathological characteristics of patients were collected simultaneously. The correlation between gene expression and clinicopathological characteristics was investigated. Out of the 9 clinicopathological parameters, 6 were associated with several of the 14 genes analyzed. Patient gender was associated with TYMS and TOP2A. Clinical stage was associated with VEGFR2, KIT and HER2. There was weak correlation between primary tumor size of ≤3 cm and the expression level of KIT. The mRNA expression levels of VEGFR2 and HER2 correlated with distant metastasis. BRCA1, TYMS, TOP2A and HER2 were associated with histological type. Smoking correlated with higher expression levels of BRCA1, TYMS and TOP2A and lower expression levels of PDGFRβ. The results were suggestive of correlation between the clinicopathological parameters of the NSCLC patients and the mRNA expression levels of certain lung cancer-related genes, including BRCA1, TYMS, TOP2A, PDGFRβ, VEGFR2, KIT and HER2.

Does histology predict survival of advanced non-small cell lung cancer patients treated with platin-based chemotherapy? An analysis of the Eastern Cooperative Oncology Group Study E1594

INTRODUCTION

We conducted this analysis to determine whether survival of advanced NSCLC patients treated with platin-based chemotherapy doublets involving paclitaxel, docetaxel or gemcitabine was dependent on histological subtypes and treatment regimen.

METHODS

We retrospectively analyzed data from E1594, a front-line phase III study in which advanced NSCLC patients were randomized to receive one of four regimens: cisplatin-paclitaxel, cisplatin-gemcitabine, cisplatin-docetaxel, and carboplatin-paclitaxel. Patients were classified into four histology groups: squamous cell (SCC), adeno- (AC), large cell (LCC) and others including not otherwise specified (O/NOS) carcinoma. Logrank test was performed to compare overall survival (OS) and progression free survival (PFS) distributions according to histology as well as treatment.

RESULTS

Of 1139 patients including 716 men and 423 women, AC was the most common subtype (56.8%), followed by SCC (19.7%), O/NOS (17.0%) and LCC (6.5%). Men were more likely to have SCC and women were more likely to have AC (p = 0.002). Among the four histology groups, there was no imbalance in regard to race, performance status, weight loss, brain metastasis or treatment. In each histology group, we found no significant difference in OS and PFS between the four chemotherapy regimens. Conversely, in each treatment arm, the survival outcome was similar between the four histology subtypes.

CONCLUSIONS

Our analysis suggests that histology does not predict survival benefit in advanced NSCLC patients treated with first-line platin-based doublets involving paclitaxel, docetaxel or gemcitabine.

Comparative study analyzing survival and safety of bevacizumab/carboplatin/paclitaxel and cisplatin/pemetrexed in chemotherapy-naïve patients with advanced non-squamous bronchogenic carcinoma not harboring EGFR mutation

Purpose

The majority of Egyptian patients with lung cancer present at a late stage of the disease. Bevacizumab/carboplatin/paclitaxel, as well as cisplatin plus pemetrexed, are both standard regimens for advanced non-squamous bronchogenic cancer. This study compares both regimens, in terms of efficacy and toxicity profile, in Egyptian patients.

Patients and methods

This is a randomized Phase II study comparing toxicity profile and survival in 41 chemotherapy-naïve patients with stage IIIB or IV non-squamous NSCLC, with an ECOG performance status of 0 to 2. The epidermal growth factor receptor (EGFR) mutation detection was performed prior to treatment of all patients. Patients in the first group received: bevacizumab 7.5 mg/m² on Day 1 and Day 15; carboplatin area under the curve-5 on Day 1; and paclitaxel 60 mg/m² on Day 1, Day 8, and Day 15 every 4 weeks. In the second group, patients received cisplatin 75 mg/m² and pemetrexed 500 mg/m² every 3 weeks.

Results

The combination of bevacizumab/carboplatin/paclitaxel demonstrated higher Grade III–IV toxicity than cisplatin/pemetrexed regarding sensory/motor neuropathy (P = 0.06), DVT (P = 0.23), proteinuria (P = 0.23), and hypertension (P = 0.11), as well as Grade II alopecia (P = 0.001); however, no significant difference in toxicities between both arms was recorded regarding nausea and vomiting (P = 0.66), hematological toxicity, febrile neutropenia (P = 1) and fatigue (P = 0.66). Progression-free survival was similar for both treatment arms with a median of 6 months (P = 0.978). Overall median survival was comparable in both arms, 16.07 months versus 16.01 months (P = 0.89).

Conclusion

Bevacizumab/carboplatin/paclitaxel and cisplatin/pemetrexed provided meaningful and comparable efficacy in advanced non-squamous bronchogenic carcinoma not harboring EGFR mutation. No significant difference in toxicity was observed between both treatment arms, apart from bevacizumab/carboplatin/paclitaxel-related risks as DVT, hypertension, proteinuria, sensory/motor neuropathy, and alopecia.

Pharmacogenomic assessment of outcomes of pemetrexed-treated patients with adenocarcinoma of the lung

PURPOSE

The main objective of this study was to evaluate the association between polymorphisms of the target genes of pemetrexed and clinical outcomes in non-small cell lung cancer (NSCLC) patients treated with pemetrexed.

MATERIALS AND METHODS

We assessed polymorphisms at 8 sites in 4 genes [thymidylate synthase (TS), dihydrofolate reductase (DHFR; 1610, 680, 317, intron 1), methylenetetrahydrofolate reductase (MTHFR; 677, 1298), glycinamide ribonucleotide formyl transferase (GARFT; 2255)] associated with pemetrexed metabolism using polymerase chain reaction, gene scanning, and restriction fragment length polymorphism analysis in 90 patients with adenocarcinoma of the lung.

RESULTS

Survival was significantly longer with pemetrexed in patients with TS 3RGCC/3RGCC or 3RGGC/3RGGC compared with the other groups (PFS; 5.2 months vs. 3.7 months, p=0.03: OS; 31.8 months vs. 18.5 months, p=0.001). Patients with DHFR 680CC experienced fatigue more frequently (50% vs. 8.6%, p=0.008). Polymorphisms of MTHFR and GARFT were not significantly associated with clinical outcomes of pemetrexed.

CONCLUSION

The TS genotype was associated with survival and one DHFR polymorphism was associated with fatigue in NSCLC patients treated with pemetrexed. Further large prospective studies are required to identify other biomarkers that affect patients being treated with pemetrexed for adenocarcinoma of the lung.

Significance of folate receptor alpha and thymidylate synthase protein expression in patients with non-small-cell lung cancer treated with pemetrexed

INTRODUCTION

Folate receptor alpha (FRA) regulates cellular uptake of folates and antifolates. Information about FRA protein expression in metastatic non-small-cell lung cancer (NSCLC) is limited. We investigated FRA as a biomarker for pemetrexed-based chemotherapy and compared it with thymidylate synthase (TS), the main target of pemetrexed.

METHODS

Pretreatment tumor specimens from 207 patients with advanced NSCLC were assessed for FRA and TS protein expression by immunohistochemistry using the H-score (range, 0-300) and correlated to patients' clinicopathological data, radiographic response, progression-free survival (PFS), and overall survival (OS).

RESULTS

Low total (cytoplasmic and nuclear) TS protein expression (H-score < 210) was associated with improved PFS (median: 5.6 versus 3.5 months; hazard ratio [HR] = 0.6379, p = 0.0131) and prolonged OS (median: 22.5 versus 11.5 months; HR = 0.5680,p = 0.0107). An association between lower TS levels and response to pemetrexed-based therapy was found-mean H-score 187 ± 5, median 180 for responders versus mean H-score 201 ± 4, median 210, for non-responders, p = 0.0244. High intracellular FRA expression (H-score ≥110) was associated with prolonged OS (28.9 versus 11.7 months, HR = 0.5316, p = 0.0040) and a trend for association with PFS (5.6 versus 4.1 months, HR = 0.7395, p = 0.0801) was noted. Membranous FRA expression was seen in 83% of patients, moreover, high membranous expression (H-score ≥20) was associated with improved PFS (5.6 versus 3.7 months, HR = 0.6445, p = 0.0306) and OS (22.1 versus 11.5 months, HR = 0.5378, p = 0.0131).

CONCLUSIONS

A large number of NSCLC patients have high expression of FRA and/or a low level of TS expression. Expression levels of FRA and TS were associated with clinical benefit from pemetrexed therapy.

Pemetrexed for the treatment of non-small cell lung cancer

INTRODUCTION

Non-small cell lung cancer (NSCLC) is a major cause of cancer-related death worldwide. Although advanced NSCLC is still incurable, various anti-neoplastic agents have become available for the treatment of this disease. Pemetrexed , a multi-target folate antagonist, has improved the survival of non-squamous NSCLC patients. Currently, pemetrexed is approved for first-line treatment in combination with a platinum derivate, for second-line treatment as a single agent and, more recently, as maintenance treatment after first-line chemotherapy.

AREAS COVERED

The authors analyzed the state of the art of pemetrexed through a review of the literature. Clinical trials and meta-analyses involving pemetrexed in NSCLC were evaluated. Pemetrexed improved survival of non-squamous NSCLC in first-line, maintenance, and second-line treatments; this benefit is limited to non-squamous histology. Because pemetrexed has become part of the standard of care, current clinical trials are designed to compare it to other investigational combinations. Limited data on resectable disease are available, and additional clinical trials are being conducted.

EXPERT OPINION

Pemetrexed has shown effectiveness and a favorable toxicity profile. Histology-driven indications and the relationship of pemetrexed with thymidylate synthase expression suggest that a more precise definition of predictive biomarkers could be further investigated.

Pharmacogenetics of conventional chemotherapy in non-small-cell lung cancer: a changing landscape?

Pharmacogenetics might be used to select patients who may benefit from specific chemotherapy that best matches the individual and tumor genetic profile, thus allowing maximum activity and minimal toxicity. Even if most studies in non-small-cell lung cancer yielded contradictory results, several potential biomarkers for sensitivity/resistance to platinum compounds, gemcitabine, taxanes and pemetrexed have been proposed. However, these markers need to be validated within larger prospective randomized trials of customized chemotherapy in homogeneous populations. Other critical points include the optimization/standardization of technical procedures, and further studies to unravel the extremely complex regulation of gene function. From this perspective, the evaluation of key factors influencing genotype-phenotype relationships, such as miRNAs, and functional studies to clarify pharmacokinetic/pharmacodynamic interactions, are fundamental for the pharmacogenetic optimization of cancer chemotherapy. Finally, limitation of the traditional pharmacogenetic approach relying only on candidate genes suspected of affecting drug response is now being overcome by the use of novel genome-wide studies.

Thymidylate synthase and ERCC1 as predictive markers in patients with pulmonary adenocarcinoma treated with pemetrexed and cisplatin

Increased expression of thymidylate synthase (TS) is thought to be associated with resistance to antifolate drugs such as pemetrexed. Excision repair cross-complementation group 1 (ERCC1) is a predictive marker for platinum-based chemotherapy. This study evaluated whether the expression of TS and ERCC1 proteins is associated with clinical outcomes of the patients with pulmonary adenocarcinoma who were treated with pemetrexed/cisplatin as first-line chemotherapy. The expressions of TS and ERCC1 were evaluated by immunohistochemistry in biopsy specimens obtained from patients with pulmonary adenocarcinoma who had received pemetrexed/cisplatin as first-line treatment. Patients were categorized according to median H-score. Response rate (RR), progression-free survival (PFS) and overall survival (OS) were analyzed retrospectively. Both low TS and ERCC1 expressions were significantly associated with better RR (p = 0.037 and p = 0.015, respectively) and longer PFS (p < 0.001 and p = 0.004, respectively). Low ERCC1 expression was also associated with longer OS (p = 0.003) while TS only showed a trend (p = 0.105). TS expression was independent predictor for the better PFS in multivariate analysis (hazard ratio [HR] = 0.32, 95% confidence interval [CI]: 0.14-0.76). Combining the two markers, the low TS/low ERCC1 group showed significantly longer PFS (HR = 0.48, 95% CI: 0.26-0.75) and OS (HR = 0.57, 95% CI: 0.36-0.89) compared with high TS/high ERCC1 group. Protein expressions of TS and ERCC1 were associated with clinical outcomes in patients with pulmonary adenocarcinoma who were treated with pemetrexed/cisplatin as first-line chemotherapy. TS and ERCC1 protein expressions can be potential predictive markers in this setting.

Impact of thymidylate synthase protein expression on efficacy of chemotherapy in advanced lung cancer patients

Advanced lung cancer is primarily treated with platinum combination chemotherapy, however, its prognosis remains poor. The aim of this study was to examine the correlation between the expression of thymidylate synthase (TS) in cancer tissues and the efficacy of chemotherapy in patients with advanced lung cancer in order to clarify the role of TS in the overall response. In total, 120 patients diagnosed with lung cancer between June 2004 and December 2010 at Nihon University Hospital, Tokyo, Japan, were included in this study. Cancer tissue specimens were obtained from the included patients by surgery or bronchofiberscopy prior to treatment. The expression of TS protein was evaluated using specimens immunostained with anti-TS antibody and H-scoring. TS protein expression tended to be higher in smokers compared with non-smokers. Overall survival (OS) (median value) was significantly prolonged in the low TS expression group compared with the high TS expression group. More favorable therapeutic effects were observed in the high TS expression group compared with the low TS expression group, when carboplatin + paclitaxel combined chemotherapy (CbPac therapy) was used. When the therapeutic effects were compared between CbPac therapy and carboplatin + pemetrexed combined chemotherapy (CbPem therapy) in the high TS expression group, prolongation of OS (median value) was observed with CbPac therapy. The present study suggests that TS protein expression is a critical factor in determining the efficacy of CbPac therapy in lung cancer. CbPac therapy is more effective when TS protein is highly expressed in lung cancer tissue.

New radiotherapy and chemoradiotherapy approaches for non-small-cell lung cancer

Recent advances in systemic cytotoxic and molecularly targeted therapies coupled with technologic strides in radiotherapy have the potential to improve outcomes for patients with non-small-cell lung cancer (NSCLC). Investigations are ongoing to identify optimal cytotoxin-based chemoradiotherapy platforms. The influence of specific histologic and molecular mutation status on the combination of targeted therapies and radiotherapy is also being actively studied. Although there are no convincing randomized phase III data to date supporting a survival advantage for combining molecularly targeted agents with radiation or chemoradiotherapy in the setting of locally advanced NSCLC, phase II and III studies targeted to elderly patients and those with poor performance status are elucidating preferred chemoradiotherapy strategies. Radiotherapy dose escalation did not improve chemoradiotherapy outcomes, although increasing radiation dose-intensity with modern techniques is being actively studied. As modern radiotherapy techniques have been shown to improve outcomes of some patients with limited metastatic disease, investigations are ongoing regarding how to optimally integrate them with standard chemotherapy platforms.

Pathology and personalized medicine in lung cancer

SUMMARY Personalized medicine for patients with non-small-cell lung cancer is a reality now and its use will only increase in the future. Pathology is key in supporting this approach to treatment decision-making, by performing the most complete and accurate histological subtyping of tumors possible, supported by predictive immunohistochemistry and the assessment of relevant biomarkers. The need for these extra diagnostic steps emphasizes the importance of maximizing tissue yields from biopsy procedures. Although multiplex approaches may allow simultaneous assessment of several biomarkers, there will remain a need for different types of test (e.g., immunohistochemistry, as well as mutation testing). Next-generation technologies for DNA sequencing are a great hope for extensive genetic analysis of single samples, provided various technical and logistical problems can be solved. All such laboratory activity must be supported by high-quality internal procedures and external quality-assurance schemes.

Thymidylate synthase expression and molecular alterations in adenosquamous carcinoma of the lung

Thymidylate synthase expression is known to be higher in squamous cell carcinoma than in adenocarcinoma of the lung. It is thought that this is the reason for the poor efficacy of pemetrexed in squamous cell carcinoma. However, there is limited data on thymidylate synthase expression in adenosquamous carcinoma, a distinct subtype of lung cancer containing both squamous and glandular differentiation. Furthermore, molecular alterations like epidermal growth factor receptor and Kirsten rat sarcoma 2 viral oncogene homolog mutations, which are seen in adenocarcinomas, are not well understood in mixed histology tumors such as adenosquamous carcinoma. In our study, we sought to better characterize adenosquamous tumors of the lung. Using immunohistochemistry to evaluate thymidylate synthase protein levels, we found that the expression of thymidylate synthase in these mixed tumors roughly parallel that of squamous cell carcinoma, instead of falling in between squamous cell and adenocarcinoma. Of note, in adenosquamous samples, the expression of thymidylate synthase was more closely correlated within the two components than would be expected by random chance alone. Also, we had a relatively high rate of epidermal growth factor receptor (11%) and Kirsten rat sarcoma 2 viral oncogene homolog (33%) mutations in these specimens, with the mutations showing convergence in both the glandular and squamous components upon microdissection. Our results indicate that adenosquamous carcinomas are not simple mixtures of their two histological components; they rather behave as their own entity, and it is important to further understand their behavior. Given the similarity of thymidylate synthase expression between squamous cell and adenosquamous carcinoma, and that thymidylate synthase is the main target of pemetrexed, we extrapolate that pemetrexed may also have inferior clinical activity in adenosquamous carcinoma.

Achaete-scute homolog 1 as a marker of poorly differentiated neuroendocrine carcinomas of different sites: a validation study using immunohistochemistry and quantitative real-time polymerase chain reaction on 335 cases

Neuroendocrine carcinomas show overlapping morphological and immunohistochemical features independently of their site of origin, which makes identification of the primary location problematic when they are diagnosed as metastases of unknown origin. Neuroendocrine carcinomas are easily morphologically differentiated from neuroendocrine tumors in surgical material, although this distinction can be difficult when using small biopsy specimens. The diagnostic usefulness of different transcription factors as site-specific markers or as discriminating markers between neuroendocrine carcinomas and neuroendocrine tumors has been previously studied with sometimes contradictory results. In this respect, the role of achaete-scute homolog 1 has been poorly investigated, although some recent findings demonstrate its expression in neuroendocrine carcinomas. Using immunohistochemistry and quantitative real-time polymerase chain reaction, we investigated the expression of achaete-scute homolog 1 in 335 neuroendocrine neoplasms (194 neuroendocrine carcinomas and 141 neuroendocrine tumors) of different sites, to check its possible utility as diagnostic marker. High concordance between immunohistochemical and molecular findings was found. Achaete-scute homolog 1 expression was identified in 82% of lung neuroendocrine carcinomas and 70% of extrapulmonary neuroendocrine carcinomas. Achaete-scute homolog 1 was not detected in any gastroenteropancreatic neuroendocrine tumor and was found in only a minority of lung carcinoids. The diagnostic sensitivity and specificity of achaete-scute homolog 1 expression were 82.4% and 89.7% in distinguishing neuroendocrine carcinomas from neuroendocrine tumors of the lung, 40.6% and 100% to differentiate extrapulmonary neuroendocrine carcinomas from neuroendocrine tumors, and 82.4% and 59.4% in distinguishing lung from extrapulmonary neuroendocrine carcinomas. Our data suggest that achaete-scute homolog 1 is not a site-specific marker. However, achaete-scute homolog 1 may be proposed as a diagnostic marker of poor differentiation and may help to differentiate neuroendocrine carcinomas from neuroendocrine tumors in difficult cases.

Association of thymidylate synthase gene 3'-untranslated region polymorphism with sensitivity of non-small cell lung cancer to pemetrexed treatment: TS gene polymorphism and pemetrexed sensitivity in NSCLC

Background

Thymidylate synthase (TS) is a key enzyme responsible for DNA synthesis and repair. Altered expression of TS protein or TS gene polymorphisms has been associated with cancer progression and treatment response. This study investigated the expressions of TS and its gene SNPs in non-small cell lung cancer (NSCLC), and then its association with sensitivity to pemetrexed treatment. Immunohistochemistry and qRT-PCR were performed on 160 resected NSCLC specimens and corresponding normal tissues to assess the expressions of TS protein and TS mRNA, and for associations with clinicopathological data. Blood samples of 106 lung adenocarcinoma patients were examined for polymorphisms of the TS gene 3’-UTR 1494del 6 bp, which was then investigated for associations with responses of the patients to pemetrexed treatment and survival.

Results

Expression of both TS protein and its mRNA was elevated in NSCLC tissues compared with matched normal tissues, and significantly higher in lung squamous cell carcinoma than in lung adenocarcinoma. TS expression was associated with poor tumor differentiation. Furthermore, the genotyping data showed that 56% of lung adenocarcinoma patients had the TS gene 3’-UTR 1494 bp (−6 bp/-6 bp) genotype and the rest had TS gene 3’-UTR 1494 bp (−6 bp/+6 bp). There was no TS 3’-UTR 1494 bp (+6 bp/+6 bp) genotype in any patients. Statistical analysis revealed that gender, tumor stage, and TS 3’-UTR 1494del 6 bp polymorphism were significant prognostic factors after short-term pemetrexed treatment. Log-rank analysis revealed that patients with the (−6 bp/-6 bp) genotype had significantly better progression-free and overall survival than patients with (−6 bp/+6 bp).

Conclusions

This study showed that TS protein is highly expressed in NSCLC and that polymorphisms of TS 3’-UTR 1494del 6 bp are associated with sensitivity of lung adenocarcinoma patients to pemetrexed treatment. This suggests that TS gene polymorphisms should be further evaluated as prognostic markers for personalized therapy in lung adenocarcinoma.

Chemotherapy effectiveness after first-line gefitinib treatment for advanced lepidic predominant adenocarcinoma (formerly advanced bronchioloalveolar carcinoma): exploratory analysis of the IFCT-0401 trial

HYPOTHESIS

This study explored whether chemotherapy after first-line gefitinib was effective in patients with advanced lepidic predominant adenocarcinoma (LPA), formerly advanced bronchioloalveolar carcinoma, who were enrolled in the Intergroupe Francophone de Cancérologie Thoracique (IFCT)-0401 trial.

METHODS

Overall, 88 patients presenting advanced LPA were enrolled in the IFCT-0401 trial, receiving gefitinib as first-line therapy. No predefined second-line treatment was mandatory in the case of progression or limiting toxicity under gefitinib. However, the carboplatin plus paclitaxel regimen was recommended for patients with a performance status (PS) 0 or 1 and gemcitabine monotherapy for those with a PS 2. For these patients, data concerning treatment efficacy was collected from the IFCT-0401 trial database.

RESULTS

In total, 47 patients (53%) received second-line treatment after the failure of gefitinib, with 43 having PS 0 or 1. Regarding treatment, 43 were treated with chemotherapy, with 38 receiving a platinum-doublet regimen (taxane-based, n = 29; gemcitabine-based, n = 9) and five receiving monotherapy (gemcitabine, n = 3; pemetrexed, n = 2). The overall response rate (ORR) to chemotherapy was 21% (95% confidence interval [CI]: 10-36), disease control rate 56% (95% CI: 40-71), and median progression-free survival (PFS) 3.0 months (95% CI: 2.4-4.9). For patients receiving a platinum doublet (n = 38), ORR was 21% (95% CI: 10-37), with disease control rate being 55% (95% CI: 38-71), and median PFS 2.9 months (95% CI: 2.4-4.4). For patients receiving taxane-based regimen (n = 29) and gemcitabine-based regimen (n = 12), ORR was 28% and 0%, respectively, with a median PFS of 3.3 and 2.0 months, respectively, (p = 0.0243). The two patients receiving pemetrexed experienced a prolonged response. Multivariate Cox model analysis revealed that only the use of taxane-based chemotherapy or pemetrexed was related to PFS.

CONCLUSION

Platinum-doublet chemotherapy showed some effectiveness in treating advanced LPA patients after first-line gefitinib. Our findings also suggest that taxane-based chemotherapy and pemetrexed should be investigated further in future clinical trials.

Current state-of-the-art therapy for advanced squamous cell lung cancer

Squamous cell carcinoma (SCC) represents the second most common histologic subtype of lung cancer (preceded only by adenocarcinoma). SSC of the lung is prevalently diagnosed in smokers and has been described as a preferentially centrally located tumor in which the main airways are commonly involved. Clinically, it presents with predominant locoregional signs and symptoms, but in recent years an increasing frequency of peripheral SCC of the lung has been reported. Pathologic diagnosis can be easily made through light microscopy and immunohistochemistry. The treatment approach for early-stage disease does not differ from that of other histologic subtypes of non-small cell lung cancer; in locally advanced unresectable or metastatic disease, doublet chemotherapy regimens (including cisplatin or carboplatin and a third-generation agent such as gemcitabine, taxanes, or vinorelbine) remain the cornerstone of front-line systemic treatment. Conversely, a single agent, mainly docetaxel, is the preferred treatment in second-line treatment. In unselected patient populations, targeted therapies have been extensively tested in combination with cytotoxic chemotherapy with disappointing results because of increased toxicity or lack of improvement in efficacy outcomes. Genomic alterations in SCC of the lung have not been comprehensively characterized, and no molecularly targeted therapies have been specifically developed for the treatment of this disease, but recently immune checkpoints have emerged as new therapeutic agent.

Messenger RNA and protein expression of thymidylate synthase and DNA repair genes in thymic tumors

BACKGROUND

Thymic epithelial tumors include several entities with different biologic behavior. Chemotherapy is indicated in advanced disease, but limited data exist on gene expression correlation with the response to chemotherapeutic agents.

PATIENTS AND METHODS

A series of 69 thymic neoplasms (7 A-, 6 AB-, 6 B1-, 10 B2-, 14 B3-thymomas, 22 carcinomas and 4 combined tumors) was collected to assess gene expression of thymidylate synthase (TS), excision repair cross complementing-1 (ERCC1), ribonucleotide reductase subunit 1 (RRM1), topoisomerase 2α (TOP2A) and mTOR.

RESULTS

A strong linear correlation between TS gene and protein expression was observed (P<0.0001, R=0.40). TS expression was significantly lower in pure A-thymomas and thymic carcinomas (P<0.0001) and progressively decreasing from B1-type to thymic carcinomas (B1>B2>B3>C; P<0.0001). RRM1 and TOP2A mRNA expression levels were significantly correlated with TS levels (both P=0.03) with a similar trend of expression among histotypes. RRM1 and TOP2A high levels were significantly correlated with high TS (P=0.03) and low tumor stages (I-II) (P<0.0001 and P<0.01, respectively). No relevant changes of ERCC1 and mTOR were detected.

CONCLUSIONS

Low TS and, to a minor extent, RRM1 and TOP2A expression were detected in aggressive thymic tumors. These findings should be prospectively considered in selecting the most appropriate chemotherapy.

Systemic therapy of advanced non-small cell lung cancer: major-developments of the last 5-years

The standard palliative treatment for advanced stage NSCLC remains a platinum doublet but by tailoring chemotherapy according to tumour histology the results can be improved through using pemetrexed-containing schemas in non-squamous-cell disease. In addition, maintenance chemotherapy appears to be effective in patients achieving clinical benefit by induction therapy. Targeted therapy based on the presence of activating epidermal growth factor receptor (EGFR) activating mutations or EML4-ALK gene rearrangement is becoming standard practice with high median survival rates, up to 30 months. There are still numerous other molecular targeted drugs in development. This review presents the most recent relevant progress in systemic anti-cancer therapy of advanced NSCLC in the past 5 years and delineates today's new treatment options.

High expression of folate receptor alpha in lung cancer correlates with adenocarcinoma histology and EGFR [corrected] mutation

INTRODUCTION

Folate receptor alpha (FRα) and reduced folate carrier-1 (RFC1) regulate uptake of folate molecules inside the cell. FRα is a potential biomarker of tumors response to antifolate chemotherapy, and a target for therapies using humanized monocloncal antibody. Information on the protein expression of these receptors in non-small-cell lung carcinoma (NSCLC) is limited.

MATERIAL AND METHODS

Expressions of FRα and RFC1 were examined by immunohistochemistry (IHC) in 320 surgically resected NSCLC (202 adenocarcinomas and 118 squamous cell carcinomas) tissue specimens and correlated with patients' clinico-pathologic characteristics. Folate receptor α gene (FOLR1) mRNA expression was examined using publicly available microarray datasets. FRα expression was correlated with thymidylate synthase and p53 expression in NSCLCs, and with epidermal growth factor receptor (EGFR) and V-Ki-ras2 Kirsten rat sarcoma viral (KRAS) gene mutations in adenocarcinomas.

RESULTS

NSCLC overexpressed FRα and RFC1. In a multivariate analysis, lung adenocarcinomas were more likely to express FRα in the cytoplasm (OR = 4.39; p < 0.0001) and membrane (OR = 5.34; p < 0.0001) of malignant cells than squamous cell carcinomas. Tumors from never-smokers were more likely to express cytoplasmic (OR = 3.35; p<0.03) and membrane (OR = 3.60; p=0.0005) FRα than those from smokers. In adenocarcinoma, EGFR mutations correlated with higher expression of membrane FRα and FOLR1 gene expressions. High levels of FRα expression was detected in 42 NSCLC advanced metastatic tumor tissues.

CONCLUSIONS

FRα and RFC1 proteins are overexpressed in NSCLC tumor tissues. The high levels of FRα in lung adenocarcinomas may be associated to these tumors' better responses to antifolate chemotherapy and represents a potential novel target for this tumor type.

Thymidylate synthase protein expression by IHC and gene copy number by SISH correlate and show great variability in non-small cell lung cancer

INTRODUCTION

Increased expression of thymidylate synthase (TS) is thought to be associated with resistance to TS-targeting drugs, e.g., pemetrexed.

METHODS

TS protein expression (PE) and gene copy number (GCN) were assayed using immunohistochemistry and silver in situ hybridization, respectively, on primary tumors of 189 resected non-small cell lung patients. Associations with pathological and clinical features and prognosis were explored.

RESULTS

Median immunohistochemistry H-score was 220 (range, 10-380) on a 0 to 400 scale; 17% of the patients had a TS expression of 300 or more. TS PE expression did not significantly differ by histology and did not significantly associate with disease-free survival (DFS) or overall survival (OS). However, there was a tendency for increased DFS (p = 0.12) and OS (p = 0.12) in PE positive (>median) squamous-cell carcinoma (SCC) patients. Median GCN was 2.5 genes/nucleus (range, 1.4-9.6); 29% of patients had GCN of 3 or more, 7% of 4 or more and 0.8% amplification. GCN differed by histology (p = 0.015); 50% of SCCs having GCN more than 2.5 versus 32% of adenocarcinomas. There was no significant relationship between TS GCN and DFS or OS; however, a trend toward better DFS (p = 0.18) and OS (p = 0.10) with increased GCN in SCCs was observed. TS GCN was significantly correlated with PE (r = 0.30, p = 0.0009).

CONCLUSIONS

TS PE and GCN vary widely in non-small cell lung and correlate significantly with each other. TS GCN is higher in SCCs, whereas TS PE does not associate with histological subtypes, clinical features, or survival. Variability of TS PE and GCN may indicate potential benefit from pemetrexed therapy in selected SCC patients.

Challenges in Implementing Personalized Medicine for Lung Cancer within a National Healthcare System

The traditional approach to the treatment of advanced non-small cell lung cancer (NSCLC) relied on the uniform use of cytotoxic chemotherapy. Over the last eight years, this paradigm of care has been shifting towards the use of molecularly targeted agents. Epidermal growth factor receptor (EGFR) mutations have emerged as an important biomarker for these targeted agents and multiple studies have shown that tyrosine kinase inhibitors (TKI) that inhibit EGFR are superior to traditional chemotherapy in patients possessing an EGFR mutation. Nationally funded health care systems face a number of challenges in implementing these targeted therapies, most related to the need to test for biomarkers that predict likelihood of benefiting from the drug. These obstacles include the challenge of getting a large enough tissue sample, workload of involved specialists, reliability of subtyping in NSCLC, differences in biomarker tests, and the disconnect between the funding of drugs and the related biomarker test. In order to improve patient outcomes, in a national healthcare system, there is a need for governments to accept the changing paradigm, invest in technology and build capacity for molecular testing to facilitate the implementation of improved patient care.

Proteomic profiling identifies dysregulated pathways in small cell lung cancer and novel therapeutic targets including PARP1

Small cell lung cancer (SCLC) is an aggressive malignancy distinct from non-small cell lung cancer (NSCLC) in its metastatic potential and treatment response. Using an integrative proteomic and transcriptomic analysis, we investigated molecular differences contributing to the distinct clinical behavior of SCLCs and NSCLCs. SCLCs showed lower levels of several receptor tyrosine kinases and decreased activation of phosphoinositide 3-kinase (PI3K) and Ras/mitogen-activated protein (MAP)/extracellular signal-regulated kinase (ERK) kinase (MEK) pathways but significantly increased levels of E2F1-regulated factors including enhancer of zeste homolog 2 (EZH2), thymidylate synthase, apoptosis mediators, and DNA repair proteins. In addition, PARP1, a DNA repair protein and E2F1 co-activator, was highly expressed at the mRNA and protein levels in SCLCs. SCLC growth was inhibited by PARP1 and EZH2 knockdown. Furthermore, SCLC was significantly more sensitive to PARP inhibitors than were NSCLCs, and PARP inhibition downregulated key components of the DNA repair machinery and enhanced the efficacy of chemotherapy.

SIGNIFICANCE

SCLC is a highly lethal cancer with a 5-year survival rate of less than 10%. To date, no molecularly targeted agents have prolonged survival in patients with SCLCs. As a step toward identifying new targets, we systematically profiled SCLCs with a focus on therapeutically relevant signaling pathways. Our data reveal fundamental differences in the patterns of pathway activation in SCLCs and NSCLCs and identify several potential therapeutic targets for SCLCs, including PARP1 and EZH2. On the basis of these results, clinical studies evaluating PARP and EZH2 inhibition, together with chemotherapy or other agents, warrant further investigation.

Pemetrexed-based chemotherapy in patients with advanced, ALK-positive non-small cell lung cancer

BACKGROUND

Anaplastic lymphoma kinase (ALK)-positive non-small-cell lung cancer (NSCLC) is highly responsive to crizotinib. To determine whether ALK-positive NSCLC is also sensitive to pemetrexed, we retrospectively evaluated progression-free survival (PFS) of ALK-positive versus ALK-negative patients who had been treated with pemetrexed-based chemotherapy for advanced NSCLC.

PATIENTS AND METHODS

We identified 121 patients with advanced, ALK-positive NSCLC in the USA, Australia, and Italy. For comparison, we evaluated 266 patients with advanced, ALK-negative, epidermal growth factor receptor (EGFR)-wild-type NSCLC, including 79 with KRAS mutations and 187 with wild-type KRAS (WT/WT/WT). We determined PFS on different pemetrexed regimens.

RESULTS

Among 70 ALK-positive patients treated with a platinum/pemetrexed regimen, the median PFS (mPFS) was 7.3 months (95% confidence interval (CI) 5.5-9.5). The mPFS of 51 ALK-positive patients treated with single-agent pemetrexed or nonplatinum/pemetrexed combinations was 5.5 months (2.8-9.0). For ALK-negative patients, PFS on all pemetrexed-based regimens was similar to that of ALK-positive patients, except in the specific setting of first-line platinum/pemetrexed where the mPFS was only 4.2 and 5.4 months in KRAS and WT/WT/WT patients, respectively. However, among patients with a never/light-smoking history (0-10 pack-year smoking history) treated with first-line platinum/pemetrexed, there was no difference in PFS between ALK-positive and ALK-negative patients.

CONCLUSIONS

PFS on pemetrexed or nonplatinum/pemetrexed combinations was similar in ALK-positive and ALK-negative patients. PFS on first-line platinum/pemetrexed may be prolonged in never/light-smoking patients regardless of ALK status.

Expression of DNA repair and replication genes in non-small cell lung cancer (NSCLC): a role for thymidylate synthetase (TYMS)

Background

BRCA1 (B), ERCC1 (E), RRM1 (R) and TYMS (T) mRNA expression has been extensively studied with respect to NSCLC patient outcome upon various chemotherapy agents. However, these markers have not been introduced into clinical practice yet. One of the reasons seems to be lack of a standard approach for the classification of the reported high/low mRNA expression. The aim of this study was to determine the prognostic/predictive impact of B, E, R, T in routinely-treated NSCLC patients by taking into account the expression of these genes in the normal lung parenchyma.

Methods

B, E, R, T mRNA expression was examined in 276 NSCLC samples (real-time PCR). The normal range of B, E, R, T transcript levels was first determined in matched tumor – normal pairs and then applied to the entire tumor series. Four main chemotherapy categories were examined: taxanes-without-platinum (Tax); platinum-without-taxanes (Plat); taxanes/platinum doublets (Tax/Plat); and, all-other combinations.

Results

In comparison to remotely located normal lung parenchyma, B, E, R, T mRNA expression was generally increased in matched tumors, as well as in the entire tumor series. Therefore, tumors were classified as expressing normal or aberrant B, E, R, T mRNA. In general, no marker was associated with overall and progression free survival (OS, PFS). Upon multivariate analysis, aberrant intratumoral TYMS predicted for shorter PFS than normal TYMS in 1st line chemo-naïve treated patients (p = 0.012). In the same setting, specific interactions were observed for aberrant TYMS with Plat and Tax/Plat (p = 0.003 and p = 0.006, respectively). Corresponding patients had longer PFS in comparison to those treated with Tax (Plat: HR = 0.234, 95% CI:0.108-0.506, Wald’s p < 0.0001; Tax/Plat: HR = 0.242, 95% CI:0.131-0.447, Wald’s p < 0.0001). Similar results were obtained for PFS in 1st line chemo-naïve and (neo)adjuvant pre-treated patients. Adenocarcinoma, early disease stage, and treatment with Tax/Plat doublets independently predicted for prolonged OS in patients who received only one line of treatment (adjuvant or 1st line).

Conclusion

Classifying intratumoral B, E, R, T mRNA expression in comparison to normal lung may facilitate standardization of these parameters for prospective studies. With this approach, NSCLC patients with aberrant intratumoral TYMS expression will probably fare better with platinum-based treatments.

Expression of thymidylate synthase and orotate phosphoribosyltransferase in thymic carcinoma

Thymic carcinoma is a rare thymic epithelial tumor in which chemotherapy for advanced disease has not yet been established. Thymidylate synthase (TS) and orotate phosphoribosyltransferase (OPRT) protein expression levels in thymic carcinoma were evaluated as possible indicators of the anticancer activity of 5-fluorouracil (5-FU) drugs using immunohistochemistry (IHC). A total of 24 samples of thymic carcinoma were used in the present study. The tumor sections were immunohistochemically stained for TS and OPRT. As a comparison with thymic carcinoma, we also assessed the TS and OPRT protein expression levels in 55 lung cancer samples. The TS expression was positive in 12 of 24 thymic carcinoma samples (50%) and OPRT expression was positive in 10 (42%). The association between TS and OPRT expression and Masaoka stages of thymic carcinoma was analyzed. The TS and OPRT expressions in stage IV were significantly higher compared to that in stages I, II or III. We also compared the TS and OPRT expression levels between thymic carcinoma and lung cancer (33 adenocarcinomas and 22 squamous cell carcinomas). TS expression in thymic carcinoma was significantly lower compared with lung squamous cell carcinoma. OPRT expression in thymic carcinoma was significantly higher compared to lung adenocarcinoma. The combination of a relatively low expression of TS and high expression of OPRT suggests an improved antitumor effect of 5-FU drugs in thymic carcinoma compared to in lung carcinoma.