Molecular markers and targeted therapy with novel agents: prospects in the treatment of non-small cell lung cancer

SNPs in predicting clinical efficacy and toxicity of chemotherapy: walking through the quicksand

In the "precision medicine" era, chemotherapy still remains the backbone for the treatment of many cancers, but no affordable predictors of response to the chemodrugs are available in clinical practice. Single nucleotide polymorphisms (SNPs) are gene sequence variations occurring in more than 1% of the full population, and account for approximately 80% of inter-individual genomic heterogeneity. A number of studies have investigated the predictive role of SNPs of genes enrolled in both pharmacodynamics and pharmacokinetics of chemotherapeutics, but the clinical implementation of related results has been modest so far. Among the examined germline polymorphic variants, several SNPs of dihydropyrimidine dehydrogenase (DPYD) and uridine diphosphate glucuronosyltransferases (UGT) have shown a robust role as predictors of toxicity following fluoropyrimidine- and/or irinotecan-based treatments respectively, and a few guidelines are mandatory in their detection before therapy initiation. Contrasting results, however, have been reported on the capability of variants of other genes as MTHFR, TYMS, ERCC1, XRCC1, GSTP1, CYP3A4/3A5 and ABCB1, in predicting either therapy efficacy or toxicity in patients undergoing treatment with pyrimidine antimetabolites, platinum derivatives, irinotecan and taxanes. While formal recommendations for routine testing of these SNPs cannot be drawn at this moment, therapeutic decisions may indeed benefit of germline genomic information, when available. Here, we summarize the clinical impact of germline genomic variants on the efficacy and toxicity of major chemodrugs, with the aim to facilitate the therapeutic expectance of clinicians in the odiern quicksand field of complex molecular biology concepts and controversial trial data interpretation.

Structure-Guided Synthesis and Mechanistic Studies Reveal Sweetspots on Naphthyl Salicyl Hydrazone Scaffold as Non-Nucleosidic Competitive, Reversible Inhibitors of Human Ribonucleotide Reductase

Ribonucleotide reductase (RR), an established cancer target, is usually inhibited by antimetabolites, which display multiple cross-reactive effects. Recently, we discovered a naphthyl salicyl acyl hydrazone-based inhibitor (NSAH or E-3a) of human RR (hRR) binding at the catalytic site (C-site) and inhibiting hRR reversibly. We herein report the synthesis and biochemical characterization of 25 distinct analogs. We designed each analog through docking to the C-site of hRR based on our 2.7 Å X-ray crystal structure (PDB ID: 5TUS). Broad tolerance to minor structural variations preserving inhibitory potency is observed. E-3f (82% yield) displayed an in vitro IC50 of 5.3 ± 1.8 μM against hRR, making it the most potent in this series. Kinetic assays reveal that E-3a, E-3c, E-3t, and E-3w bind and inhibit hRR through a reversible and competitive mode. Target selectivity toward the R1 subunit of hRR is established, providing a novel way of inhibition of this crucial enzyme.

Current Status of Cetuximab for the Treatment of Patients with Solid Tumors

Objective:

To review the pharmacology, pharmacokinetics, clinical evidence, and safety, as well as the potential directions for use, of the epidermal growth factor receptor (EGFR) monoclonal antibody cetuximab.

Data Sources:

A MEDLINE search (1966–December 2005) was conducted using the following terms: cetuximab, Erbitux, C225, epidermal growth factor receptor, and EGFR. Additional information was obtained via meeting abstracts, bibliographies from relevant articles, national guidelines, and the manufacturer.

Study Selection and Data Extraction:

Preclinical and clinical trials utilizing cetuximab in the treatment of solid tumors were selected from the data sources. All published, randomized clinical trials involving cetuximab in treatment of metastatic colorectal cancer and studies providing a description of the pharmacology, pharmacokinetics, safety, or efficacy were included in this review.

Data Synthesis:

Many solid tumors overexpress EGFR, making it an ideal target for anticancer agents. Cetuximab is the only EGFR monoclonal antibody commercially available and is approved for the treatment of EGFR-expressing, metastatic colorectal cancer in patients refractory or intolerant to irinotecan. Data on patients with other solid tumors are encouraging with cetuximab used as monotherapy or in combination with chemotherapy, radiation, or other targeted agents. Common adverse effects include dermatologic and hypersensitivity reactions.

Conclusions:

Further clinical data are necessary to clearly define the role of cetuximab in the treatment of patients with solid malignancies, with emphasis on survival and quality-of-life benefits relative to its cost.

A laboratory prognostic index model for patients with advanced non-small cell lung cancer

Purpose

We aimed to establish a laboratory prognostic index (LPI) in advanced non-small cell lung cancer (NSCLC) patients based on hematologic and biochemical parameters and to analyze the predictive value of LPI on NSCLC survival.

Patients and Methods

The study retrospectively reviewed 462 patients with advanced NSCLC diagnosed between 2000 and 2010 in a single institution. We developed an LPI that included serum levels of white blood cells (WBC), lactate dehydrogenase (LDH), albumin, calcium, and alkaline phosphatase (ALP), based on the results of a Cox regression analysis. The patients were classified into 3 LPI groups as follows: LPI 0: normal; LPI 1: one abnormal laboratory finding; and LPI 2: at least 2 abnormal laboratory findings.

Results

The median follow up period was 44 months; the median overall survival (OS) and median progression-free survival (PFS) were 11 and 6 months, respectively. A multivariate analysis revealed that the following could be used as independent prognostic factors: an Eastern Cooperative Oncology Group performance status score (ECOG PS) ≥2, a high LDH level, serum albumin <3 g/dL, serum calcium>10.5 g/dL, number of metastases>2, presence of liver metastases, malignant pleural effusion, or receiving chemotherapy ≥4 cycles. The 1-year OS rates according to LPI 0, LPI 1, and LPI 2 were 54%, 34%, and 17% (p<0.001), respectively and 6-month PFS rates were 44%, 27%, and 15% (p<0.001), respectively. The LPI was a significant predictor for OS (Hazard Ratio (HR): 1.41; 1.05–1.88, p<0.001) and PFS (HR: 1.48; 1.14–1.93, p<0.001).

Conclusion

An LPI is an inexpensive, easily accessible and independent prognostic index for advanced NSCLC and may be helpful in making individualized treatment plans and predicting survival rates when combined with clinical parameters.

Association between polymorphisms of DNA repair genes and survival of advanced NSCLC patients treated with platinum-based chemotherapy

BACKGROUND

Single nucleotide polymorphism (SNP) in DNA repair genes can be used to explain the differences in survival of platinum-treated non-small cell lung cancer (NSCLC) patients regardless of their performance status. To define the role of DNA repair gene SNPs in NSCLC patients, we investigated the association between survival and 12 different SNPs of 9 DNA repair genes.

METHODS

340 patients were treated with platinum-based chemotherapy. Polymorphisms were detected by real time PCR with TaqMan probe, using genomic DNA extracted from peripheral blood samples. Multivariate logistic or Cox regression analyses were used to adjust for possible confounding variables.

RESULTS

The median overall survival time was 15 months and it was significantly longer in patients harboring ERCC1 118 C/T or T/T allele: 18 months as compared to 13.8 months for the C/C allele (P=0.014). Subgroup analysis revealed that ERCC1 118 C/T or T/T was associated with increased survival in elderly patients (P=0.018), male (P=0.022), squamous carcinoma (P=0.003), smoker (P=0.076) and those treated with non-gemcitabine/cisplatin or carboplatin (non-GP/GC) regimen (P=0.023). XRCC3C/C was associated with better survival in non-gemcitabine/cisplatin treated patients (P=0.014). Both of CCNH-V270A C/C or C/T and XPD 751 A/A showed a significant longer survival in the squamous cell carcinoma subgroup (P=0.047 and P=0.034 respectively).

CONCLUSION

Present data indicates that ERCC1 118 C/T or T/T might provide a better prognostic predictive marker of NSCLC patients treated with platinum-based chemotherapy, mainly in elderly subgroup, male, squamous carcinoma, smoker and those treated with non-GP/GC regimen.

Smoking and prognostic factors in an observational setting in patients with advanced non-small cell lung carcinoma

BACKGROUND

This prospective observational study estimated the effect of prognostic factors, particularly continued smoking during therapy, on survival in advanced non-small cell lung cancer (NSCLC) patients receiving gemcitabine-platinum. Further, prognostic factors were used to build a survival model to improve prognosis prediction in naturalistic clinical settings.

METHODS

Eligibility criteria included: Stage IIIB/IV NSCLC, no prior chemotherapy, and Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1. A Cox regression model was constructed and validated by randomizing patients into two datasets (Construction [C]:Validation [V]; 3:1 ratio). Country, disease stage, hypercalcemia, "N" factor, weight reduction, performance status, and superior vena cava obstruction were pre-defined variables forced into the model. Continued smoking was tested with adjustment for these variables.

RESULTS

One thousand two hundred and fourteen patients (C=891 and V=323) were enrolled. The final predictive model, established in the Construction dataset, identified four significant (p≤0.05) and independent predictors of survival, which were disease stage, performance status, gemcitabine-platinum regimen, and T-stage. Smoking during therapy was not significantly associated with survival (Hazard Ratio [95% CI]: 0.955 [0.572, 1.596], p=0.8618; versus never smokers).

CONCLUSIONS

Although continued smoking during therapy was not significantly associated with shorter survival, the model developed in this study forms an evidence-based approach to assessing prognosis in advanced stage NSCLC.

The Surgical Management of Lung Cancer

Since the introduction of the pneumonectomy as a technically feasible strategy for the treatment of lung cancer, surgical resection has played a pivotal role in the management of early stage non-small cell lung carcinoma (NSCLC). In the last two decades, surgical, medical, and radiation oncologists have produced a growing body of evidence to support the combination of neoadjuvant or adjuvant treatments with standard surgical resection, to improve disease-free and overall survival for specific patient subgroups. Furthermore, alternatives to aggressive surgical management have evolved for patients who are medically inoperable due to compromised pulmonary function or other comorbidities. In this review, surgical options and multimodal treatment strategies are discussed, as well as completed and ongoing clinical trials addressing the surgical management of NSCLC.

Ribonucleotide reductase M1 (RRM1) 2464G>A polymorphism shows an association with gemcitabine chemosensitivity in cancer cell lines

OBJECTIVES

Significant variability in the efficacy and toxicity of an anticancer drug is observed in cancer patients. Currently, there are no standard tools for prediction of a patient's tumor response or his risk of adverse events to chemotherapy.

METHODS

We investigate an association between polymorphisms of gemcitabine metabolism-related genes and its chemosensitivity in vitro using 62 human cancer cell lines of various origins. Polymorphisms of gemcitabine metabolism-related genes of deoxycytidine monophosphate deaminase (DCTD), deoxycytidine kinase (DCK) and ribonucleotide reductase M1 (RRM1) were evaluated using the CEQ8000 Genetic analysis system and GeneDoc software. Chemosensitivity of gemcitabine was expressed as an IC50 using MTT assay.

RESULTS

The frequency of the polymorphisms was 21% in DCTD 315T>C, 45.2% in RRM1 1082C>A, 59.7% in RRM1 2455A>G, and 79% in RRM1 2464G>A. When examining the association between these polymorphisms and IC50, only the RRM1 2464G>A showed the tendency to be more chemosensitive to gemcitabine (P=0.011), and haplotypes containing 2464G>A polymorphism also showed the association with chemosensitivity when compared to wild-type RRM1 (G2464G). We could not see the significant differences of mRNA expression level with real-time PCR between cell lines according to G2464A polymorphism. In oligonucleotide microarray 73 GenBank Accession Number (69 genes) were selected which expressed differently between RRM1 wild-type and the G2464A polymorphism.

CONCLUSIONS

RRM1 2464G>A polymorphism demonstrated an association with gemcitabine sensitivity, which needs functional studies with co-expressing genes and prospective clinical studies for the clinical application as a predictive bio-marker.

Therapeutic resistance in lung cancer

Despite considerable progress over the last 25 years in the systemic therapy of lung cancer, intrinsic and acquired resistance to chemotherapeutic agents and radiation remains a vexing problem. The number of mechanisms of therapeutic resistance in lung cancer has expanded considerably over the past three decades, and the crucial role of stress resistance pathways is increasingly recognised as a cause of intrinsic and acquired chemo- and radiotherapy resistance. This paper reviews recent evidence for stress defence proteins, particularly RALBP1/RLIP76, in mediating intrinsic and acquired chemotherapy and radiation resistance in human lung cancer.

Erlotinib in non-small cell lung cancer: a review

Erlotinib (Tarceva, OSI-774; Pfizer, Inc.) is an orally-active, targeted inhibitor of the epidermal growth factor receptor (EGFR/HER1), which is part of a key regulatory pathway in cancer. Patients with advanced, incurable non-small cell lung cancer (NSCLC) may derive a clinical benefit from first- and second-line chemotherapy, but third-line treatment with available cytotoxic agents is not effective. Remarkably, EGFR/HER1 antagonists have demonstrated activity as second- and even third-line treatment for this disease. Erlotinib is the first of this novel class of drug to demonstrate a statistically significant and clinically relevant difference in overall survival, progression free survival and time to disease related symptoms (cough, pain, shortness of breath) compared with treatment with best supportive care in patients who have failed standard first- or second-line chemotherapy. This paper reviews the pharmacology, preclinical and clinical data to support the use of erlotinib in NSCLC.

How will lung cancer be treated in the future?

Lung cancer is still considered the leading cause of cancer-related deaths in industrialized countries. Despite improvements in cancer diagnosis and therapy, the present 5-year survival rate of 14% is only slightly higher than the survival rate of 8% in the early 1960s. At present, a survival plateau has been reached by the current management of lung cancer, including surgery, chemo- and radiotherapy. Although prevention and early diagnosis are undoubtedly important, more innovative treatment approaches and new agents that affect alternate mechanisms in tumor cells are needed. Since molecular targets of tumorigenesis and metastasis are currently the focus of lung cancer research, this review will summarize the most important molecular approaches and clinical trials of novel therapeutics.

Beta1 integrin inhibitory antibody induces apoptosis of breast cancer cells, inhibits growth, and distinguishes malignant from normal phenotype in three dimensional cultures and in vivo

Current therapeutic approaches to cancer are designed to target molecules that contribute to malignant behavior but leave normal tissues intact. beta(1) integrin is a candidate target well known for mediating cell-extracellular matrix (ECM) interactions that influence diverse cellular functions; its aberrant expression has been implicated in breast cancer progression and resistance to cytotoxic therapy. The addition of beta(1) integrin inhibitory agents to breast cancer cells at a single-cell stage in a laminin-rich ECM (three-dimensional lrECM) culture was shown to down-modulate beta(1) integrin signaling, resulting in malignant reversion. To investigate beta(1) integrin as a therapeutic target, we modified the three-dimensional lrECM protocol to approximate the clinical situation: before treatment, we allowed nonmalignant cells to form organized acinar structures and malignant cells to form tumor-like colonies. We then tested the ability of beta(1) integrin inhibitory antibody, AIIB2, to inhibit tumor cell growth in several breast cancer cell lines (T4-2, MDA-MB-231, BT474, SKBR3, and MCF-7) and one nonmalignant cell line (S-1). We show that beta(1) integrin inhibition resulted in a significant loss of cancer cells, associated with a decrease in proliferation and increase in apoptosis, and a global change in the composition of residual colonies. In contrast, nonmalignant cells that formed tissue-like structures remained resistant. Moreover, these cancer cell-specific antiproliferative and proapoptotic effects were confirmed in vivo with no discernible toxicity to animals. Our findings indicate that beta(1) integrin is a promising therapeutic target, and that the three-dimensional lrECM culture assay can be used to effectively distinguish malignant and normal tissue response to therapy.

EGFR protein overexpression and gene amplification in squamous cell carcinomas of the esophagus

Overexpression of epidermal growth factor receptor (EGFR) is observed in many cancers, sometimes accompanied by gene amplification. Recently, several clinical therapies targeting EGFR were developed, but the eligibility criteria for these therapies is not fully established. To develop such eligibility criteria for esophageal squamous cell carcinoma (ESCC), we sought to clarify: (i) the exact frequency of EGFR overexpression, (ii) the relationship between protein overexpression and gene amplification, (iii) the relationship between gene amplification and specific gene mutations and (iv) the correlation between the status of EGFR and clinical or pathological features. Immunohistochemistry revealed that EGFR protein is overexpressed in 53 (50%) of the 106 ESCC examined. Fluorescence in situ hybridization (FISH) indicated clear EGFR gene amplification in 15 of the 53 tumors, somewhat higher EGFR copy in 32 cases, and no increase in 6 cases. Gene amplification was significantly associated with high level overexpression. Direct sequencing of exons 19 and 21 of EGFR revealed no mutations in 15 tumors exhibiting gene amplification, and no mutations in 25 tumors not exhibiting gene amplification. Overexpression of EGFR was significantly correlated with depth of invasion of the tumor. In conclusion, anti-EGFR therapies may be appropriate for patients with ESCC. We assume that combined analyses by immunohistochemistry/FISH would clarify aberrations in protein and gene function, and could help to identify those patients who may benefit from anti-EGFR therapy.

Is there a prognostic role of K-ras point mutations in the serum of patients with advanced non-small cell lung cancer?

The purpose of this study was to investigate the prognostic significance of K-ras mutations in circulating DNA in advanced non-small lung cancer (NSCLC) patients. Serum samples were assessed prior to platinum-based chemotherapy start in 67 patients with advanced NSCLC (stage IIIB or IV), treated between April 1999 and June 2002. Patients were not previously treated with chemotherapy. K-ras oncogene mutations at codon 12 were analyzed by genomic amplification and direct sequencing of the patient's DNA present in serum. Pre-treatment serum was available in all 67 patients. Twenty patients (30%) demonstrated K-ras mutations while 47 patients (70%) had wild-type K-ras. Among K-ras mutations, the amino acid glycine was substituted by cystein in 90% and valine in 10%. When patients were grouped according to K-ras genotype, there was no significant difference for any of the baseline patient characteristics. There was a tendency towards a higher response rate for patients with K-ras mutations versus wild-type K-ras in serum, however not statistically significant (p=0.37). Median progression-free survival was 7.3 months versus 5.5 months in patients with mutations and with wild-type K-ras, respectively (p=0.23). For median overall survival time, the mutation group was comparable to the wild-type K-ras group with 12.5 and 11.4 months, respectively (p=0.28). In conclusion, there were no significant differences between the patients with K-ras mutations and those with wild-type genotype with respect to baseline patient characteristics, response rates, progression-free survival, or overall survival.

High mutagen sensitivity in peripheral blood lymphocytes predicts poor overall and disease-specific survival in patients with stage III non-small cell lung cancer treated with radiotherapy and chemotherapy

PURPOSE

To investigate whether the bleomycin sensitivity assay, an in vitro peripheral blood lymphocyte assay, can predict outcome in patients with inoperable stage III non-small-cell lung cancer (NSCLC) treated with definitive radiotherapy and chemotherapy.

EXPERIMENTAL DESIGN

We identified 102 patients with inoperable stage III NSCLC cell lung cancer treated with definitive radiotherapy and chemotherapy. The patients' pretreatment peripheral blood lymphocyte cultures were treated with the radiomimetic mutagen bleomycin. An index of bleomycin sensitivity was determined by counting the number of chromatid breaks in 50 metaphases. The correlation between bleomycin sensitivity (expressed as mean breaks per cell) and clinical outcome was analyzed.

RESULTS

High bleomycin sensitivity (defined as a mean of >1.02 chromatid breaks/cell, representing the third quartile of bleomycin sensitivity) predicted poor disease-specific survival and overall survival. The 6-year disease-specific survival was 27% in patients with high bleomycin sensitivity compared with 46% in patients without such sensitivity (P = 0.0094). The association remained statistically significant when adjusted for smoking status, age, and radiation dose. The 6-year overall survival was 19% for patients with high bleomycin sensitivity and 29% for those without (P = 0.0193). There was a trend toward worse local regional control and worse disease-free survival among patients with high bleomycin sensitivity. There was no difference between the two groups in distant metastasis-free survival or radiation treatment-related complications.

CONCLUSIONS

High bleomycin sensitivity correlated with poor overall survival and disease-specific survival in these patients with stage III NSCLC treated with radiotherapy and chemotherapy. Bleomycin sensitivity may function as a biomarker for poor clinical outcome for this group of patients.

Circulating tumour-derived DNA and RNA markers in blood: a tool for early detection, diagnostics, and follow-up?

BACKGROUND

Lung cancer is the most common cause of cancer death in developed countries. The prognosis is poor with only 10-15% of patients surviving 5 years after diagnosis. This dismal prognosis is attributed to the lack of efficient diagnostic methods for early detection and lack of successful treatment for metastatic disease. Within the last decade, rapid advances in molecular biology and radiology have provided a rational basis for improving early detection and patients' outcome. A non-invasive blood test effective in detecting preneoplastic changes or early lung cancer in high risk individuals has been perceived as a holy grail by cancer researchers.

METHODS

The introduction of polymerase chain reaction (PCR)-based technology in the late 1980s and its refinement over the last 10 years have allowed us to detect and quantify extremely small amounts of tumour-derived nucleic acids. This has led to an increased knowledge of the molecular pathogenesis of lung cancer and a basis for the use of DNA and RNA markers in blood for early cancer detection, diagnostics, and follow-up. Common genetic alterations in lung carcinogenesis are already well known. We reviewed published literature on DNA and RNA in plasma or serum in lung cancer patients up to 2004, with particular emphasis on reports published since 1995.

RESULTS

Twenty-two clinical studies have evaluating the role of DNA and RNA aberrations in the blood of lung cancer patients. A total of 1618 (range 10-163/study) cases and 595 (range 10-120/study) control cases were evaluated, and overall plasma/serum abnormalities were found in 43% (range 0-78%) of cases and 0.8% of healthy controls. For (1) total DNA and gene expression levels, 61% (range 53-71%) of cases and 0.9% of controls; (2) oncogene mutations, 16% (range 0-30%) and 0%; (3) microsatellite alterations, 46% (range 24-71%) and 21% (controls with non-malignant pulmonary disease); (4) promoter methylation, 42% (range 5-73%) and 0%; (5) tumour-related RNAs, 54% (range 39-78%) and 6%. In general, the studies contain small series of lung cancer patients and even smaller or missing case control groups.

CONCLUSION

The analysis of circulating DNA or RNA in plasma is a promising non-invasive diagnostic tool, requiring only a limited blood sample. Its wide applicability and potential importance will possibly lead to increasing clinical impact in the near future. However, large prospective clinical studies are needed to validate and standardise any tests for DNA or RNA alteration in plasma or serum of high risk individuals or patients with established lung cancer.

The biology of non-small-cell lung cancer: identifying new targets for rational therapy

Lung cancer, and in particular non-small-cell lung cancer (NSCLC), remains the leading cause of cancer death throughout the world. Almost three decades ago, the major concern was to identify whether cisplatin or cisplatin-based chemotherapy enhanced survival in metastatic NSCLC, and whether any survival benefit compensated for cisplatin-related toxicity. Over the last 10 years, significant advances have been achieved in molecular biology, including the identification of critical genes related to the pathogenesis of NSCLC, which have formed the basis for new targeted therapeutic approaches. These new approaches include novel agents against established chemotherapeutic targets such as thymidylate synthetase as well as agents that inhibit novel targets such as growth factor receptors and proteins important in angiogenesis. With the advent of genomic technologies that can identify patterns of gene expression, the hope is that therapy will be tailored to the genetic pattern of the patients's tumor, and individualized treatments that minimize toxicity and maximize efficacy can be developed.

Excision repair cross-complementation group 1 polymorphism predicts overall survival in advanced non-small cell lung cancer patients treated with platinum-based chemotherapy

DNA repair is a critical mechanism of resistance to platinum-based chemotherapy. Excision repair cross-complementation group 1 (ERCC1) is the lead enzyme in the nucleotide excision repair process. Increased ERCC1 mRNA levels are related directly to platinum resistance in various cancers. We examined the association between two polymorphisms of ERCC1, codon 118 C/T and C8092A, which are associated with altered ERCC1 mRNA levels and mRNA stability, and overall survival (OS) in 128 advanced non-small cell lung cancer patients treated with platinum-based chemotherapy. The two polymorphisms were in linkage disequilibrium. There was a statistically significant association between the C8092A polymorphism and OS (P = 0.006, by log-rank test), with median survival times of 22.3 (C/C) and 13.4 (C/A or A/A) months, respectively, suggesting that any copies of the A allele were associated with poor outcome. No statistically significant association was found for the codon 118 polymorphism and OS (P = 0.41, by log-rank test), with median survival times of 19.9 (T/T), 16.1 (C/T), and 13.3 (C/C) months, respectively. In conclusion, the ERCC1 C8092A polymorphism may be a useful predictor of OS in advanced non-small cell lung cancer patients treated with platinum-based chemotherapy.

Gene Expression Profiling in Non-Small Cell Lung Cancer

Non-small cell lung cancer (NSCLC) is the most common cause of premature death from malignant disease in western countries. A better understanding of the molecular mechanisms underlying NSCLC etiology, pathogenesis, and therapeutics will lead to improved clinical outcomes. Recent technological advances in gene expression profiling (in particular, with cDNA and oligonucleotide microarrays) allow the simultaneous analysis of the expression of thousands of genes. In this review, the technology of global gene expression profiling is discussed, and the progress made thus far with it in NSCLC is reviewed. A new molecular classification of NSCLC has been developed, which has provided important insights into etiology and pathogenesis. Other studies have found potential biomarkers for NSCLC that may be of use in diagnosis, screening, and assessing the effectiveness of therapy. Finally, advances have been made in the understanding of the molecular mechanisms of NSCLC progression and the molecular mechanisms of action of currently used cytotoxic drugs. This may facilitate the improvement of current therapeutics and the identification of novel targets. Taken together, these advances hold the promise of an improved understanding of the molecular biology of NSCLC and its treatment, which in turn will lead to improved outcomes for this deadly disease.