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

Predictive role of CYFRA 21-1 for S-1 monotherapy in non-small cell lung cancer patients

BACKGROUND

S-1, an oral fluoropyrimidine derivative, is widely used for the treatment of several solid tumors. However, there are no predictive markers for its effectiveness.

METHODS

We retrospectively screened 108 patients with advanced non-small cell lung cancer (NSCLC) treated via S-1 monotherapy and investigated its relationship with cytokeratin 19 fragment (CYFRA 21-1) and CEA pretreatment levels.

RESULTS

Sixty-one patients with high CYFRA 21-1 levels had a statistically significant shorter progression-free survival (PFS) and overall survival (OS) than 46 patients with normal levels (median PFS = 42 days vs. 70 days, respectively; p = 0.0014; median OS = 197 days vs. 316 days, respectively, p = 0.0239).

CONCLUSIONS

Serum CYFRA 21-1 levels have predictive and prognostic roles in the management of patients with advanced NSCLC on S-1 monotherapy.

Association of MTHFR and TYMS gene polymorphisms with the susceptibility to HCC in Egyptian HCV cirrhotic patients

Identification of host genetic factors influencing the risk of developing hepatocellular carcinoma (HCC) in patients with chronic hepatitis C virus (HCV) infection may help to refine patients' selection to benefit from specific preventative measures and/or adapted screening policies. Thus, this study aimed to investigate the association of MTHFR c.677C > T and c.1298A > C in addition to TYMS 3'-UTR 6-bp ins/del polymorphisms with the susceptibility to HCV-related HCC in an Egyptian population. Polymerase chain reaction-restriction fragment length polymorphism was performed to genotype the polymorphisms in 194 HCV-infected patients subdivided into liver cirrhotic (LC, n = 104) and HCC (n = 90) patients as well as 100 healthy subjects. In healthy controls, the MTHFR c.677C > T polymorphism under the homozygous and recessive models (p = 0.005) and the c.1298A > C polymorphism under all the tested genetic models (p-values range from < 0.001 to 0.007) were associated with an increased risk of HCC. In LC patients, the MTHFR c.677C > T polymorphism under the homozygous, dominant, and recessive models (p-values range from 0.001 to 0.007), as well as MTHFR c.1298A > C under the homozygous model only (p = 0.014), increased the susceptibility to HCC. The C/C and T/C haplotypes of MTHFR c.677C > T and MTHFR c.1298A > C polymorphisms were contributed to an increased risk of healthy subjects to develop HCC (p-values range from < 0.001 to 0.015), while only the T/C haplotype was associated with the progression of HCC in LC patients (p = 0.001). In conclusion, MTHFR c.677C > T and c.1298A > C in addition to their haplotypes may contribute to the development of HCV-related HCC in an Egyptian population. These findings may aid in the early diagnosis and management of HCC.

Detecting TYMS Tandem Repeat Polymorphism by the PSSD Method Based on Next-generation Sequencing

Background:

Thymidylate Synthase (TS) is an important target for folic acid inhibitors such as pemetrexed, which has considerable effects on the first-line treatment, second-line treatment and maintenance therapy for patients with late-stage Non-Small Cell Lung Cancer (NSCLC). Therefore, detecting mutations in the TYMS gene encoding TS is critical in clinical applications. With the development of Next-Generation Sequencing (NGS) technology, the accuracy of TYMS mutation detection is getting higher and higher. However, traditional methods suffer from false positives and false-negatives caused by factors like limited sequencing read length and sequencing errors.

Objective:

A method was needed to overcome the short sequencing read length and sequencing errors of NGS to make the detection of TYMS more accurate.

Methods:

In this study, we developed a novel method based on "Paired Seed Sequence Distance” (PSSD) to detect the Variable Number of Tandem Repeat (VNTR) mutation for TYMS.

Results:

With the 121 samples validated by sanger, the consistency rate of PSSD method was 85.95% (104/121), higher than the strict matching method (78.51% (95/121)). The consistency rate of the two methods was 89.26% (108/121). We also found that the PSSD method was significantly better than the strict matching method, especially in the 4R typing.

Conclusion:

Our method not only improves the detection rate and accuracy of TYMS VNTR mutations but also avoids problems caused by sequencing errors and limited sequencing length. This method provides a new solution for similar polymorphism analyses and other sequencing analyses.

Phase II Study of Pemetrexed as a Salvage Chemotherapy for Thymidylate Synthase-Low Squamous Cell Lung Cancer

PURPOSE

Squamous cell carcinomas (SqCC) of the lung often express high levels of thymidylate synthase (TS), which is associated with primary resistance to pemetrexed. We explored the efficacy of pemetrexed in a selected population of patients with lung SqCC with low TS expression.

Materials and Methods

In this single-arm phase II trial, we enrolled 32 previously-treated patients with advanced lung SqCC exhibiting low immunohistochemical staining for TS (i.e., in 10% or less of tumor cells). The primary endpoint was 12-week progression-free survival (PFS) rate.

RESULTS

Of 32 patients, eight patients (25%) had an Eastern Cooperative Oncology Group performance status of 2, and seven patients (22%) had previously received three or more lines of chemotherapy. The disease control rate from pemetrexed treatment was 30%, and no objective response was observed. The 12-week PFS rate was 24.5% (95% confidence interval [CI], 13.0 to 46.1). Median PFS was 1.3 months (95% CI, 1.3 to 2.7), and median overall survival was 11.8 months (95% CI, 8.1 to not applicable). Most of adverse events were grade 1 or 2.

CONCLUSION

Pemetrexed demonstrated modest activity as a salvage chemotherapy in patients with advanced lung SqCC with low TS expression, although its toxicity was generally manageable.

Dysregulated Pyrimidine Biosynthesis Contributes to 5-FU Resistance in SCLC Patient-Derived Organoids but Response to a Novel Polymeric Fluoropyrimidine, CF10

Chemo-immunotherapy is central to the treatment of small cell lung cancer (SCLC). Despite modest progress made with the addition of immunotherapy, current cytotoxic regimens display minimal survival benefit and new treatments are needed. Thymidylate synthase (TS) is a well-validated anti-cancer drug target, but conventional TS inhibitors display limited clinical efficacy in refractory or recurrent SCLC. We performed RNA-Seq analysis to identify gene expression changes in SCLC biopsy samples to provide mechanistic insight into the potential utility of targeting pyrimidine biosynthesis to treat SCLC. We identified systematic dysregulation of pyrimidine biosynthesis, including elevated TYMS expression that likely contributes to the lack of efficacy for current TS inhibitors in SCLC. We also identified E2F1-3 upregulation in SCLC as a potential driver of TYMS expression that may contribute to tumor aggressiveness. To test if TS inhibition could be a viable strategy for SCLC treatment, we developed patient-derived organoids (PDOs) from human SCLC biopsy samples and used these to evaluate both conventional fluoropyrimidine drugs (e.g., 5-fluorouracil), platinum-based drugs, and CF10, a novel fluoropyrimidine polymer with enhanced TS inhibition activity. PDOs were relatively resistant to 5-FU and while moderately sensitive to the front-line agent cisplatin, were relatively more sensitive to CF10. Our studies demonstrate dysregulated pyrimidine biosynthesis contributes to drug resistance in SCLC and indicate that a novel approach to target these pathways may improve outcomes.

Research progress of the clinicopathologic features of lung adenosquamous carcinoma

Adenosquamous carcinoma (ASC) of the lung, a biphasic malignant tumor arising from lung tissue, is a special subtype of non-small-cell lung cancer (NSCLC) with low incidence but high tendency of invasion and poor prognosis. ASC contains components of lung adenocarcinoma (AC) and lung squamous cell carcinoma (SCC). However, there is a remarkable difference between ASC and other NSCLCs in clinical features, suggesting that ASC is not a simple mixture of AC and SCC, but is rather a more complex carcinoma with a unique molecular phenotype. At present, the research on ASC is still rare, mostly because of its complicated molecular mechanism and unclear pathological origin. The lack of cognition of ASC limits its early diagnosis and treatment, and a set of mature and effective treatment programs has not been proposed yet. In-depth study of the molecular characteristics and clinical features of ASC will not only help to better understand the scientific issues, including phenotype switching of lung cancer, the origin of tumor development, and tumor heterogeneity, but also contribute to the development of its individualized treatment. This review summarizes the recent studies concerning the clinicopathologic features and the molecular mechanisms of ASC to further facilitate the development of its individualized treatment.

Identification of candidate biomarkers and pathways associated with SCLC by bioinformatics analysis

Small cell lung cancer (SCLC) is one of the highly malignant tumors and a serious threat to human health. The aim of the present study was to explore the underlying molecular mechanisms of SCLC. mRNA microarray datasets GSE6044 and GSE11969 were downloaded from Gene Expression Omnibus database, and the differentially expressed genes (DEGs) between normal lung and SCLC samples were screened using GEO2R tool. Functional and pathway enrichment analyses were performed for common DEGs using the DAVID database, and the protein-protein interaction (PPI) network of common DEGs was constructed by the STRING database and visualized with Cytoscape software. In addition, the hub genes in the network and module analysis of the PPI network were performed using CentiScaPe and plugin Molecular Complex Detection. Finally, the mRNA expression levels of hub genes were validated in the Oncomine database. A total of 150 common DEGs with absolute fold-change >0.5, including 66 significantly downregulated DEGs and 84 upregulated DEGs were obtained. The Gene Ontology term enrichment analysis suggested that common upregulated DEGs were primarily enriched in biological processes (BPs), including ‘cell cycle’, ‘cell cycle phase’, ‘M phase’, ‘cell cycle process’ and ‘DNA metabolic process’. The common downregulated genes were significantly enriched in BPs, including ‘response to wounding’, ‘positive regulation of immune system process’, ‘immune response’, ‘acute inflammatory response’ and ‘inflammatory response’. Kyoto Encyclopedia of Genes and Genomes pathway analysis identified that the common downregulated DEGs were primarily enriched in the ‘complement and coagulation cascades’ signaling pathway; the common upregulated DEGs were mainly enriched in ‘cell cycle’, ‘DNA replication’, ‘oocyte meiosis’ and the ‘mismatch repair’ signaling pathways. From the PPI network, the top 10 hub genes in SCLC were selected, including topoisomerase IIα, proliferating cell nuclear antigen, replication factor C subunit 4, checkpoint kinase 1, thymidylate synthase, minichromosome maintenance protein (MCM) 2, cell division cycle (CDC) 20, cyclin dependent kinase inhibitor 3, MCM3 and CDC6, the mRNA levels of which are upregulated in Oncomine SCLC datasets with the exception of MCM2. Furthermore, the genes in the significant module were enriched in ‘cell cycle’, ‘DNA replication’ and ‘oocyte meiosis’ signaling pathways. Therefore, the present study can shed new light on the understanding of molecular mechanisms of SCLC and may provide molecular targets and diagnostic biomarkers for the treatment and early diagnosis of SCLC.

Combined effect of ERCC1 and ERCC2 polymorphisms on overall survival in non-squamous non-small-cell lung cancer patients treated with first-line pemetrexed/platinum

OBJECTIVES

Polymorphisms of DNA repair genes may affect DNA repair capacity and the sensitivity of platinum doublets chemotherapy in non-small-cell lung cancer (NSCLC). We prospectively evaluated whether single nucleotide polymorphisms (SNPs) of ERCC1, ERCC2, XRCC1, and XRCC3 were associated with treatment outcome in advanced non-squamous NSCLC patients receiving pemetrexed/platinum as their first-line chemotherapy.

MATERIALS AND METHODS

Genotyping of six SNPs in four DNA repair genes in 58 patients treated with first-line pemetrexed/platinum was performed using TaqMan SNP Genotyping Assays.

RESULTS

The wild-type ERCC1 8092 (C/C) was significantly associated with a better objective response compared to the variant genotypes (C/A + A/A) (48% vs 10%, P = .005). In the multivariate Cox proportional hazards model, we found that individuals with a wild-type genotype of ERCC1 Asn118Asn, ERCC1 C8092A and ERCC2 Asp312Asn had significantly better overall survival (OS) than those with a heterozygous or homozygous variant genotype. On the other hand, the heterozygous variant genotype of ERCC2 Lys751Gln was associated with better OS than that of the wild-type genotype. We further explored the combined effect of SNPs on OS, and found a significant allele/dose-dependent trend toward decreasing OS in patients with an increasing number of unfavorable alleles among four SNPs in ERCC1 and ERCC2. The median OS of patients with two or three unfavorable alleles (30.1 and 30.5 months, respectively) was significantly longer than that of patients with 4 unfavorable alleles (11.8 months, log-rank test for trend, P = .001).

CONCLUSION

A combination of ERCC1 and ERCC2 polymorphisms may predict OS among pemetrexed/platinum treated advanced non-squamous NSCLC patients.

Protein and mRNA expression of folic acid-associated enzymes as biomarkers for the cytotoxicity of the thymidylate synthase-targeted drugs, pemetrexed and S-1, in non-small cell lung cancer

The thymidylate synthase (TS)-targeted drugs, pemetrexed and S-1, exert an important role in advanced non-small cell lung cancer (NSCLC) treatment; folic acid-associated enzymes are expected to behave as biomarkers, although their role has yet to be fully elucidated. In the present study, a single-institutional prospective analysis, in which the mRNA and protein expression levels of five folic acid-associated enzymes were evaluated with surgical specimens of NSCLC, was performed. Drug sensitivity was evaluated using a collagen gel droplet-embedded culture drug sensitivity test (CD-DST) in vitro. A total of 50 patients with NSCLC were enrolled, and the mRNA and protein expression levels of five enzymes were assessed in 47 and 46 patients, respectively. A significant association was identified between mRNA and protein expression in TS (r=0.6266), but the correlation between mRNA and protein expression levels for the other four enzymes was poor. TS mRNA expression was significantly higher in poorly differentiated tumors compared with moderately differentiated tumors (P=0.0399). TS protein expression was significantly higher in patients with pleural invasion or lymphatic invasion compared with those lacking them (P=0.027 and 0.030, respectively). CD-DST revealed that none of the tumors that were sensitive to pemetrexed, but not to S-1, were well differentiated, whereas none of the tumors that were sensitive to S-1, but not to pemetrexed, were poorly differentiated. More prominent vascular invasion was observed in the tumors that were sensitive to S-1. The only factors that exhibited the potential to discriminate the cytotoxicity of pemetrexed from S-1 were tumor differentiation grade and vascular invasion.

Thymidylate synthase gene polymorphisms as important contributors affecting hepatocellular carcinoma prognosis

BACKGROUND

Thymidylate synthase (TYMS), a key rate-limiting enzyme in the folate metabolism, plays essential roles in the development of several malignancies including hepatocellular carcinoma (HCC). Nonetheless, the association of the single nucleotide polymorphisms (SNPs) in TYMS gene with the prognosis of Chinese HCC patients remains unknown.

METHODS

A total of 492 HCC patients who underwent surgery treatment were included in this study. Five functional SNPs (rs2847153, rs2853533, rs502396, rs523230, and rs9967368) in TYMS gene were genotyped using the iPLEX genotyping system. Multivariate Cox proportional hazards regression model and Kaplan-Meier curve were used to analyze the association of SNPs with survival and recurrence of HCC patients.

RESULTS

Two SNPs (rs523230 and rs9967368) in TYMS gene were significantly associated with the overall survival of HCC patients. Patients carrying homozygous variant genotype (VV) of rs523230 had significantly decreased risk of death (hazard ratio [HR], 0.68; 95% confidence interval [CI], 0.46-1.00; P=0.048) when compared with those carrying homozygous wild-type (WW) or heterozygous (WV) genotypes, while patients carrying WV+VV genotype of rs9967368 had significantly increased risk of death (HR, 1.46; 95% CI, 1.05-2.04; P=0.026) when compared with those carrying WW genotypes. Cumulative effect analysis showed a significant dose-dependent effect of unfavorable SNPs on OS.

CONCLUSIONS

Our study for the first time demonstrates the association of SNPs in TYMS gene and clinical outcome of HCC, suggesting that rs523230 and rs9967368 in TYMS gene might be used to predict clinical outcome of Chinese HCC patients.

Pretreatment Red Blood Cell Total Folate Concentration Is Associated With Response to Pemetrexed in Stage IV Nonsquamous Non-Small-cell Lung Cancer

INTRODUCTION

Pemetrexed inhibits folate-dependent enzymes involved in pyrimidine and purine synthesis. Previous studies of genetic variation in these enzymes as predictors of pemetrexed efficacy have yielded inconsistent results. We investigated whether red blood cell (RBC) total folate, a phenotypic rather than genotypic, marker of cellular folate status was associated with the response to pemetrexed-based chemotherapy in advanced nonsquamous non-small-cell lung cancer (NSCLC).

MATERIALS AND METHODS

We conducted a prospective cohort study of patients with stage IV nonsquamous NSCLC receiving first-line chemotherapy containing pemetrexed. The pretreatment RBC total folate level was quantified using liquid chromatography mass spectrometry. We then compared the objective response rate (ORR) between patients with RBC total folate concentrations greater than and less than an optimal cutoff value determined from the receiver operating characteristic curve. A logistic regression model was used to adjust for age, sex, and the use of bevacizumab.

RESULTS

The ORR was 62% (32 of 52 patients). Receiver operating characteristic analysis was used to establish that a RBC total folate cutoff value of 364.6 nM optimally discriminated between pemetrexed responders and nonresponders. Patients with RBC total folate < 364.5 nM had an ORR of 27% compared with 71% for patients with RBC total folate > 364.5 nM (P = .01). This difference persisted after adjusting for age, sex, and the use of bevacizumab (odds ratio, 0.07; 95% confidence interval, 0.01-0.57; P = .01).

CONCLUSION

A low pretreatment RBC total folate was associated with an inferior response to pemetrexed-based chemotherapy in stage IV nonsquamous NSCLC. Larger, multicenter studies are needed to validate RBC total folate as a predictive marker of pemetrexed response.

Topoisomerase I expression is associated with prognosis in postoperative non-small cell lung cancer patients

Background

Biomarkers may help to improve non‐small cell lung cancer (NSCLC) prognosis. However, the prognostic effect of topoisomerase I (Topo I) on NSCLC is unknown. We evaluated the clinicopathologic and prognostic significance of tumor Topo I and thymidylate synthase (TS) protein expression in postoperative NSCLC patients.

Methods

One hundred and fifteen patients with postoperative NSCLC were enrolled. Topo I and TS protein were detected in removed tumors by immunohistochemistry. The correlations between Topo I/TS protein expression and clinicopathologic characters and outcomes of patients were analyzed.

Results

Increased expression of Topo I was found in 57 (49.6%) tumors. The largest diameter of the tumor was significantly different between patients with high and low Topo I expression (P = 0.035). TS staining showed that 35 (30.4%) carcinomas were TS positive. The level of TS expression was correlated with tumor differentiation (P = 0.037). Patients with low Topo I expression had significantly longer overall survival (OS) than those with high expression (P = 0.004). The correlation between Topo I expression and OS was demonstrated among patients with squamous cell carcinoma (P = 0.030) and patients in pathological tumor node metastasis stage I (P = 0.027). Topo I expression was positively correlated with TS expression in tumor tissue (R = 0.251, P = 0.007).

Conclusions

Low Topo I expression is an independent favorable prognostic factor for longer OS in postoperative NSCLC patients, especially in squamous cell carcinoma. There is a correlation between the expression of TS and Topo I in removed tumor tissue.

Thymidylate synthase expression as a predictive biomarker of pemetrexed sensitivity in advanced non-small cell lung cancer

Background

Although it has been suggested that a high level of thymidylate synthase (TYMS) gene expression in malignant tumors is related to reduced sensitivity to the antifolate drug pemetrexed, no direct evidence for such an association has been demonstrated in routine clinical samples from patients treated with the drug. The purpose of this study was to quantitatively assess the impact of TYMS gene expression in tumor cells as a predictor of the efficacy of pemetrexed therapy in patients with advanced non-small cell lung cancer (NSCLC) treated at our institution.

Methods

Sixty-two NSCLC patients were included in this study: 16 patients received platins-pemetrexed as first-line NSCLC, and 46 pemetrexed in monotherapy as second- or subsequent-line treatment. Total mRNA was isolated and the expression of TYMS was analyzed by RT-qPCR. TYMS levels were calibrated against expression in normal lung tissue.

Results

TYMS overexpression was detected in 61 % of patients and low expression in 39 %. The response rate for patients with low TYMS expression was 0.29 compared with 0.03 in patients with overexpression (P = 0.025). A significant benefit was observed in patients with low expression both in time to progression (average TTP = 56 vs. 23 months, P = 0.001) and in overall survival (average OS = 60 vs. 25 months, P = 0.002).

Conclusions

TYMS overexpression in tumor cells correlated with a reduced response to pemetrexed-containing chemotherapy and might be used as a predictive biomarker in advanced NSCLC patients.

Pharmacogenomics in the treatment of lung cancer: an update

Significant advances have been made in the analysis of the human genome in the first decades of the 21st century and understanding of tumor biology has matured greatly. The identification of tumor-associated mutations and the pathways involved has led to the development of targeted anticancer therapies. However, the challenge now in using chemotherapy to treat nonsmall-cell lung cancer is to identify more molecular markers predictive of drug sensitivity and determine the optimal drug sequences in order to tailor treatment to each patient. This approach could permit selection of patients who could benefit most from a specific type of chemotherapy by matching their tumor and individual genetic profile. Nevertheless, this potential has been limited so far by reliance on the single biomarker approach, though this is now on the way to being overcome through whole genome studies.

The Effectiveness of Pemetrexed Monotherapy Depending on Polymorphisms in TS and MTHFR Genes as Well as Clinical Factors in Advanced NSCLC Patients

In NSCLC, second-line chemotherapy using pemetrexed or docetaxel has limited efficacy and should be dedicated to selected groups of patients. Pemetrexed is an antifolate compound with the ability to inhibit enzymes (TS, DHFR and GARFT) involved in pyrimidine and purine synthesis. The objective of this study was to evaluate the association between polymorphisms of TS and MHFR genes and clinical outcomes in NSCLC patients treated with pemetrexed monotherapy. DNA was isolated from peripheral blood of 72 non-squamous NSCLC patients treated with pemetrexed. Using PCR and RFLP methods, the variable number of tandem repeats (VNTR), the G > C SNP in these repeats and insertion/deletion polymorphism of TS gene as well as 677C > T SNP in MTHFR gene were analyzed and correlated with disease control rate, progression-free survival and overall survival (OS) of NSCLC patients. Carriers of 2R/3R(G), 3R(C)/3R(G), 3R(G)/3R(G) genotypes showed significantly more frequent early progression than carriers of 2R/2R, 2R/3R(C), 3R(C)/3R(C) genotypes of TS gene (p < 0.05). Among carriers of triple 28 bp tandem repeats (3R) in TS gene and C/C genotype of MTHFR gene a significantly shorter OS was observed (HR = 3.07; p = 0.003). In multivariate analysis, significantly higher risk of death was observed in carriers of both 3R/3R genotype in TS and C/C genotype in 677C > T SNP in MTHFR (HR = 3.85; p < 0.005) as well as in patients with short duration of response to first-line chemotherapy (HR = 2.09; p < 0.005). Results of our study suggested that genetic factors may have a high predictive and prognostic value (even greater than clinical factors) for patients treated with pemetrexed monotherapy.

Pemetrexed Plus Cisplatin Versus Gemcitabine Plus Cisplatin According to Thymidylate Synthase Expression in Nonsquamous Non-Small-Cell Lung Cancer: A Biomarker-Stratified Randomized Phase II Trial

PURPOSE

We investigated whether thymidylate synthase (TS) expression is a predictive marker for the clinical outcome of pemetrexed/cisplatin in patients with nonsquamous non-small-cell lung cancer.

PATIENTS AND METHODS

Eligible patients were tested for TS expression by immunohistochemistry and stratified into either a TS-negative or a TS-positive group. After stratification, patients in each group were randomly assigned (1:1 ratio) to receive either pemetrexed/cisplatin or gemcitabine/cisplatin for a maximum of six cycles until disease progression. The primary end point was evaluation of the interaction between TS groups and treatment allocation for objective response rate.

RESULTS

Of 321 enrolled patients with nonsquamous non-small-cell lung cancer, 315 received at least one dose of study chemotherapy and were analyzed. By investigator assessment, response rates were 47% for the pemetrexed/cisplatin arm and 21% for the gemcitabine/cisplatin arm in the TS-negative group and 40% and 39%, respectively, for the TS-positive group (interaction P = .0084). By independent reviewers, response rates of pemetrexed/cisplatin and gemcitabine/cisplatin were 39% and 21%, respectively, in the TS-negative group and 40% and 48% in the TS-positive group (interaction P = .0077). The median progression-free survival times for the pemetrexed/cisplatin and the gemcitabine/cisplatin arms were 6.4 and 5.5 months, respectively, in the TS-negative group and 5.9 and 5.3 months in the TS-positive group (interaction P = .07).

CONCLUSION

With regard to response rate and progression-free survival, pemetrexed/cisplatin was superior to gemcitabine/cisplatin in the TS-negative group but not in the TS-positive group, indicative of TS expression as a potential predictive marker. Additional prospective studies involving larger cohorts are warranted to confirm the predictive role of TS expression.

Associations between TS, TTF-1, FR-α, FPGS, and overall survival in patients with advanced non-small-cell lung cancer receiving pemetrexed plus carboplatin or gemcitabine plus carboplatin as first-line chemotherapy

INTRODUCTION

Pemetrexed is effective in the treatment of non-small-cell lung cancer, mainly in nonsquamous cell carcinomas. Inhibition of thymidylate synthase (TS) is considered the key mechanism of action. Folate receptor-α facilitates uptake of pemetrexed. Polyglutamation by folylpolyglutamate synthetase enhances activity and prolongs cellular retention of pemetrexed. Thyroid transcription factor-1 (TTF-1) is mainly positive in nonsquamous cell carcinoma and has been proposed as a marker for sensitivity to pemetrexed. The aim was to investigate associations between these biomarkers and survival in patients who participated in a phase III trial comparing pemetrexed plus carboplatin with gemcitabine plus carboplatin as first-line chemotherapy in advanced non-small-cell lung cancer (n = 436). In this study, there was no difference in overall survival between the two regimens.

METHODS

Formalin-fixed, paraffin-embedded biopsies were collected. Percentages of tumor cells positive and highly positive for the biomarkers were assessed using immunohistochemistry (IHC) and an IHC score was calculated (range, 0-200).

RESULTS

Two hundred thirty-six biopsies were analyzed (pemetrexed plus carboplatin: n = 114, gemcitabine plus carboplatin: n = 122). There was a significant difference in overall survival between those with TTF-1-positive and -negative tumors (10.4 versus 6.0 months; p < 0.001) and those with a low and a high TS IHC score (9.7 versus 6.2 months; p < 0.001). Folate receptor-α and folylpolyglutamate synthetase were not significant prognostic factors. In multivariate analyses adjusting for established prognostic characteristics, TS (p = 0.002) and TTF-1 (p = 0.003) remained significant. There were no differences in survival between the treatment arms depending on biomarker scores.

CONCLUSIONS

TTF-1 positivity and low TS level were associated with prolonged survival. The associations between the biomarkers and overall survival were similar for both chemotherapy regimens.

Prospective phase II study of cisplatin plus pemetrexed with maintenance of pemetrexed for advanced non-squamous cell non-small cell lung cancer in Japan

BACKGROUND

A previous study showed a survival benefit with maintenance therapy with pemetrexed in patients with advanced non-small cell lung cancer (NSCLC). However, it remains unclear whether continuation maintenance therapy with pemetrexed is beneficial in Japanese patients. Here, we present our phase II study that assessed the efficacy and safety of cisplatin plus pemetrexed as induction chemotherapy, followed by maintenance therapy with pemetrexed in advanced NSCLC patients in Japan.

METHODS

Chemotherapy-naïve patients received 500 mg/m(2) pemetrexed and 75 mg/m(2) cisplatin on day one every three weeks for four cycles. In patients who responded to therapy or achieved stable disease, pemetrexed was continued until disease progression. The primary endpoint of this study was the progression-free survival rate at six months (PFS-6).

RESULTS

Of the 35 patients initially enrolled in the study, 18 (51%) received maintenance chemotherapy with pemetrexed. The median PFS was 6.7 months, and the PFS-6 was 60% (95% confidence interval [CI], 42-76%). Median overall survival (OS) was 15.5 months (95% CI, 8.3-22.7 months). The median PFS and OS in patients who received maintenance chemotherapy with pemetrexed were 9.5 months and 25.3 months, respectively. The most frequently noted severe toxicity during induction chemotherapy was neutropenia, which occurred in seven patients. Two patients discontinued maintenance therapy owing to prolonged grade 2 edema in one patient and grade 3 neutropenia in another.

CONCLUSION

Continuation maintenance chemotherapy with pemetrexed is associated with a survival benefit in patients who have completed induction chemotherapy for non-squamous NSCLC.

Relapsed small cell lung cancer: treatment options and latest developments

According to recent analyses, there was a modest yet significant improvement in median survival time and 5-year survival rate of limited stage small cell lung cancer (SCLC) in North America, Europe, Japan and other countries over the last 30 years. The median survival time of limited stage SCLC is 15-20 months and 5-year survival rate is 15% or less. In terms of extensive stage SCLC, a median survival time of 9.4-12.8 months and 2-year survival of 5.2-19.5% are still disappointing. Despite being highly sensitive to first-line chemotherapy and radiotherapy treatments, most patients with SCLC experience relapse within 2 years and die from systemic metastasis. While several clinical trials of cytotoxic chemotherapies and molecular targeting agents have been investigated in the treatment of relapsed SCLC, none showed a significant clinical activity to be able to exceed topotecan as second-line chemotherapy. There are problematic issues to address for relapsed SCLC, such as standardizing the treatment for third-line chemotherapy. Topotecan alone was the first approved therapy for second-line treatment for relapsed SCLC. Amrubicin is a promising drug and a variety of trials evaluating its efficacy have been carried out. Amrubicin has shown superiority to topotecan in a Japanese population, but was not superior in a study of western patients. There are some controversial issues for relapsed SCLC, such as treatment for older patients, third-line chemotherapy and efficacy of molecular targeting therapy. This article reviews current standard treatment, recent clinical trials and other topics on relapsed SCLC.

Thymidylate synthase polymorphisms in genomic DNA as clinical outcome predictors in a European population of advanced non-small cell lung cancer patients receiving pemetrexed

Background

We studied whether thymidylate synthase (TS) genotype has an independent prognostic/predictive impact on a European population of advanced non-small cell lung cancer (NSCLC) patients receiving pemetrexed.

Methods

Twenty-five patients treated with pemetrexed-based regimens were included. Genomic DNA was isolated prior to treatment. The variable number of tandem repeat (VNTR) polymorphisms, the G > C single nucleotide polymorphisms (SNP) and the TS 6-bp insertion/deletion (6/6) in the 3′ untranslated region (UTR) polymorphisms were analyzed and correlated with overall response rate (ORR), progression-free survival (PFS), overall-survival (OS) and toxicity.

Results

The genotype +6/+6 predicted a higher ORR among active/former smokers compared to +6/-6 genotype (100% vs. 50%; p = 0.085). Overall, the 3R/3R genotype predicted a higher ORR (100%) over the rest VNTR polymorphisms (p = 0.055). The presence of 3R/3R genotype significantly correlated with a superior ORR in patients without EGFR activating mutations (100%) compared to 2R/2R, 2R/3R and 3R/4R genotype (77.8%, 33.3% and 0% respectively; p = 0.017). After a median follow-up of 21 months, a trend towards a better PFS, although not significant, was found among subjects showing 3R/3R polymorphisms (p = 0.089). A significantly superior OS was found in patients showing 3R/3R genotype rather than other VNTR polymorphisms (p = 0.019). No significant correlation with the toxicity was observed.

Conclusion

In our series, 3R/3R polymorphism correlated with a superior OS. Also, this polymorphism, when associated to wild type EGFR, was related to a higher ORR to pemetrexed. Toxicity was not significantly correlated with a specific TS genotype.

Expression of thymidylate synthase predicts clinical outcomes of pemetrexed-containing chemotherapy for non-small-cell lung cancer: a systemic review and meta-analysis

PURPOSE

Observational and preclinical studies suggested an association between the expression of thymidylate synthase (TS) and clinical effects of pemetrexed-based chemotherapy in non-small-cell lung cancer (NSCLC) patients. However, the predictive value of TS for pemetrexed-containing chemotherapy regimen remained controversial. The aim of the study was to further appraise the association between the expression of TS and clinical efficacy pemetrexed-based chemotherapy in NSCLC patients.

METHODS

We searched in MEDLINE (PubMed), EMBASE, and Cochrane Library from January 1945 to May 2013. Two authors independently extracted information from the characteristics of study participants. Primary outcomes included therapeutic response (TR; i.e., complete response + partial response vs. stable disease + progressive disease), progression-free survival (PFS), and overall survival (OS). Relative risk (RR) and hazard ratio (HR) were used for evaluating the risk or hazard.

RESULTS

Eight studies were included in the meta-analysis. Better response usually appeared in NSCLC patients with a lower expression of TS [RR = 2.06 95 % confidence intervals (CI) 1.44, 2.96]. There was a significant association between TS expression and outcomes of pemetrexed-based chemotherapy for NSCLC (PFS: HR = 0.63 95 % CI 0.52, 0.76; OS: HR = 0.74, 95 % CI: 0.63, 0.88). In addition, no evidence of publication bias was observed.

CONCLUSIONS

This meta-analysis evaluated the predictive value of TS and provided evidence that NSCLC patients with lower TS expression could significantly benefit from pemetrexed-based chemotherapy. This increased level of TS was probably an independent risk factor of potential resistance against pemetrexed.

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.

Thymidylate synthase gene (TYMS) polymorphisms in sporadic and hereditary breast cancer

Background

Breast cancer (BC) is a genetic disorder characterized by growth and proliferation of breast cells in a disorderly. In Brazil, there are approximately 49.240 new cases of BC, every year. The BC etiology is still poorly understood. The BC can be sporadic (SBC) or hereditary (HBC). Recent studies have correlated gene polymorphisms with the BC, such as alterations in thymidylate synthase gene (TYMS), which are used to improve diagnosis and prevention of the disease. Polymorphisms in the TYMS gene 5’-UTR region, usually present reps double (2R) and/or triple (3R). Studies have shown that homozygous 3R/3R is overexpressed compared with 2R/2R genotype, and these polymorphic variations may contribute to individual susceptibility to the development of BC. In this context, the objective of this study was to evaluate the frequency of the TYMS 2R and 3R polymorphisms, comparing genotypic and allelic distribution with SBC and HBC patients.

Methods

In this study we included a total of 204 subjects, 70 with BC (33 with SBC, and 37 with HBC) and 134 healthy subjects (controls). The Polymerase Chain Reaction was the method used.

Results

Results demonstrated a high frequency of the 3R allele at BC, SBC, and HBC groups. The frequency of genotype 2R/3R was significantly higher in BC group. This work showed association between the 2R/3R variants (OR = 4.14, CI95% = 1.77-9.71) in the development of SBC, and 2R/2R (OR = 0.233, CI95% = 1.63-7.65) and 2R/3R (OR = 3.53, CI95% = 0.06-0.81) for developing HBC. To BC, there was association with the genotype 2R/3R (OR: 3.79, CI95% = 2.03-7.08).

Conclusion

Our results show relation to the development of BC in association with the analyzed polymorphisms.

Second-line pemetrexed versus docetaxel in Chinese patients with locally advanced or metastatic non-small cell lung cancer: a randomized, open-label study

INTRODUCTION

This randomized, open-label study compared pemetrexed versus docetaxel as second-line therapy for Chinese patients with locally advanced or metastatic non-small cell lung cancer (NSCLC). The primary endpoint tested non-inferiority of overall survival (OS) on the combined data from these patients and those in the global registration trial. Data from patients in the current study only (Chinese patients) were the basis for the study's secondary objectives.

METHODS

Patients with stage IIIB/IV disease were randomized (1:1) to receive pemetrexed (500 mg/m(2); 107 randomized; 106 treated) or docetaxel (75 mg/m(2); 104 randomized; 102 treated) on Day 1 of each 21-day cycle. Treatment continued until progressive disease, unacceptable toxicity or patient/investigator decision. All efficacy and safety data were analyzed at the pre-specified study completion; supplementary OS analyses were performed later, after additional events had been recorded.

RESULTS

The primary endpoint of OS noninferiority of pemetrexed to docetaxel was not met, the lower CL was <50% and P>0.025 (efficacy retained=97.9% [95% CLs: 47.1, 141.9]; P=0.0276), in the combined population (pemetrexed: n=390, docetaxel: n=392). Supplementary values were 101.3% (95% CLs: 57.9, 148.8), P=0.0186. For the secondary objectives, assessed in the population from the current study (pemetrexed: n=107, docetaxel: n=104), median OS was 11.7 and 12.2 months for the pemetrexed and docetaxel arms, respectively (HR [95% CLs]: 1.14 [0.78, 1.68], P=0.492). Supplementary values were 11.4 and 11.5 months, respectively (HR [95% CLs]: 1.02 [0.74, 1.40], P=0.926). Median PFS values were 2.8 and 3.1 months (HR [95% CLs]: 1.05 [0.75, 1.46], P=0.770) and ORR values were 9.6% and 4.1% (odds ratio [95% CLs]: 2.50 [0.76, 8.25], P=0.133) for pemetrexed and docetaxel, respectively. Pemetrexed-treated patients had significantly fewer drug-related grade 3-4 adverse events (pemetrexed: 20.8%, docetaxel: 40.2%; P=0.003). Few drug-related serious adverse events were reported (pemetrexed: 5 patients, docetaxel: 8 patients).

CONCLUSION

The comparable efficacy and superior tolerability of pemetrexed compared with docetaxel in this study supports the use of single-agent, second-line pemetrexed for advanced non-squamous NSCLC in Chinese patients. ClinicalTrials.gov: NCT00391274.

Correlation between thymidylate synthase gene polymorphisms and efficacy of pemetrexed in advanced non-small cell lung cancer

One of the target genes of pemetrexed (PEM), thymidylate synthase (TS), has been shown to have a close association with its efficacy. TS gene polymorphisms have been shown to be associated with the efficacy of antifolate treatment in enteron tumors. The purpose of this study was to investigate the clinical significance of TS gene polymorphisms in patients with advanced NSCLC receiving PEM-based treatment. The variable nucleoid tandem repeat in the 5′-UTR region was amplified and detected using fluorescently labeled multiplex short tandem repeat polymerase chain reaction. The polymorphism in the 3′-UTR region of the TS gene was detected using the Taqman probe. Efficacy of PEM was assessed according to the Response Evaluation Criteria in Solid Tumors, version 1.1. None of the genotypes were associated with gender, smoking status and age. Disease control rate (DCR), objective response rate (ORR) and progression-free survival (PFS) were similar between patients harboring 2R and 3R alleles (PFS, p=0.518; DCR, p=0.631; ORR, p=0.541), as well as those with a 6-bp insertion and 6-bp deletion (PFS, p=0.776; DCR, p=0.626; ORR, p=0.330). To study the combined effect of TS polymorphisms, the study population was divided into three groups: 2R&6 del, 2R&6 ins and 3R&6 del. No significant differences were observed among the different groups according to DCR (p=0.517), ORR (p=0.611) and PFS (p=0.938). In conclusion, polymorphisms of the TS gene do not appear to be a prognostic marker for advanced NSCLC patients receiving PEM-based treatment.

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.

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.