RRM1 single nucleotide polymorphism -37C-->A correlates with progression-free survival in NSCLC patients after gemcitabine-based chemotherapy

Genetic polymorphisms as potential pharmacogenetic biomarkers for platinum-based chemotherapy in non-small cell lung cancer

Platinum-based chemotherapy (PBC) is a widely used treatment for various solid tumors, including non-small cell lung cancer (NSCLC). However, its efficacy is often compromised by the emergence of drug resistance in patients. There is growing evidence that genetic variations may influence the susceptibility of NSCLC patients to develop resistance to PBC. Here, we provide a comprehensive overview of the mechanisms underlying platinum drug resistance and highlight the important role that genetic polymorphisms play in this process. This paper discussed the genetic variants that regulate DNA repair, cellular movement, drug transport, metabolic processing, and immune response, with a focus on their effects on response to PBC. The potential applications of these genetic polymorphisms as predictive indicators in clinical practice are explored, as are the challenges associated with their implementation.

Significance of Gastrokine-1 Polymorphism Rs4254535 as a Prognostic Marker and its Association with Clinical Characteristics in Chinese Lung Cancer Patients

Background: The single nucleotide polymorphism (SNP) of Gastrokine-1 (GKN1) is associated with lung cancer but its association with prognosis is not clear. Methods: Genomic DNA was extracted from the blood samples of 888 patients with lung cancer. The association between GKN1 polymorphism rs4254535 and prognostic was analyzed by the Kaplan-Meier (KM) method, Log-rank test, and Cox proportional hazards model. Results: In females and patients diagnosed with late-stage lung cancer, the CC genotype (CC vs TT, adjusted odds ratio [HR] = 0.57, 95% Confidence Interval [CI]: 0.33-0.99, P = 0.045; HR = 0.66, 95% CI: 0.48-0.92, P = 0.014) and recessive CC genotype (CC vs TT + TC, HR = 0.55, 95% CI: 0.32-0.94, P = 0.028; HR = 0.64, 95% CI: 0.47-0.89, P = 0.006) of rs4254535 conferred a better prognosis, compared with the TT and TT + TC genotype. Rs4254535 dominate TC + CC genotype, recessive CC genotype, and C allele who were adenocarcinoma patients had a significantly better prognosis. The recessive CC genotype of non-smoking patients has a better prognosis, compared to the TT + TC genotype. Additionally, in the dominant TT + TC genotype and C allele, no family history patients had a significantly better prognosis, compared to the TT genotype. Conclusion: For lung cancer patients, GKN1 polymorphism rs4254535 may be a protective genetic marker and predicts the prognosis of lung cancer patients.

The single nucleotide variant rs2868371 associates with the risk of mortality in non-small cell lung cancer patients: A multicenter prospective validation

BACKGROUND AND PURPOSE

Definitive radiation therapy (RT) with or without chemotherapy has become the standard treatment for non-metastatic unresectable non-small cell lung cancer (NSCLC). However, treatment outcomes can differ substantially and patients' genetic background could play a crucial role. Potential associations between single-nucleotide polymorphisms (SNP) in Heat shock protein beta-1 (HSPB1) and survival have been reported in prior single-institution retrospective reports.

MATERIALS AND METHODS

The current assay aims to validate such connection in a prospective multicenter study in a European cohort including 181 NSCLC patients. Median follow-up time for all patients was 13 months (range, 3-57 months).

RESULTS

The results obtained show an association between the rs2868371 GG genotype and better overall survival (HR: 0.35; 95%CI: 0.13-0.96; p = 0.042) in multivariate analysis. Two-year overall survival rate was 72% for patients carrying the rs2868371 GG genotype versus 36% for those patients harboring the rs2868371 CC/CG genotypes (p = 0.013). Additionally, the rs2868371 GG genotype was found to be associated with better disease-free survival in the multivariate analysis (HR: 0.36; 95%CI: 0.13-0.99; p = 0.048). In silico analysis of the potential functional SNP suggested significant difference in the affinity of the Glucocorticoid Receptor binding site between alternative allelic variants, confirmed by chromatin immunoprecipitation analysis displaying stronger affinity for the risk allele (C). Furthermore, our findings indicate that the rs2868371 influences (mRNA) HSPB1 expression, offering insight into the regulation of HSPB1 transcription.

CONCLUSION

The functional HSPB1 rs2868371 promoter variant may affect lung cancer survival by regulation of HSPB1 expression levels through glucocorticoid receptor interaction.

Prognostic value of ribonucleotide reductase subunit M1 (RRM1) in non-small cell lung cancer: A meta-analysis

BACKGROUND

Ribonucleotide reductase subunit 1 (RRM1) is a potential prognostic factor for non-small cell lung cancer (NSCLC). This study evaluates prognostic value of RRM1 in NSCLC patients by meta-analyzing outcomes reported in literature.

METHOD

Data were acquired from research articles retrieved after literature search in online databases. Random effects meta-analyses were conducted by pooling hazard ratios (HR). Meta-analyses of standardized mean differences (SMD) were used to evaluate overall survival (OS) and progression-free survival (PFS) between low and high RRM1 expression groups. Metaregression analyses were conducted to evaluate the factors that could affect prognostic relationship of RRM1 with treatment and survival outcomes.

RESULTS

23 studies (3148 patients) were included. RRM1 expression was not meaningfully associated with prognosis of NSCLC even when the reference (HR = 1) was either low RRM1 expression (0.918 [95% CI 0.833, 1.003]) or high RRM1 expression (0.834 [0.625, 1.043]). OS was significantly longer in low RRM1 expression group compared to high RRM1 expression group (SMD 0.73 [0.36, 1.09]; P < 0.0001). PFS was not significantly different between low and high RRM1 expression groups (SMD 0.08 [-0.29, 0.45]; p = 0.68). Age was inversely associated with HR (p = 0.001) even when reference was low RRMI (p = 0.027) or high RRM1 (p = 0.006). Age was positively associated with OS in both low and high RRM1 groups.

CONCLUSION

In meta-analysis of studies which used gemcitabine-based therapies, higher RRM1 expression is found to associated with shorter OS but not PFS. HR depicting relationship between RRM1 expression and OS/PFS/treatment response could not demonstrate a prognostic role of RRM1 in NSCLC patients.

Adverse prognostic impact of TGFB1 T869C polymorphism in non-small-cell lung cancer

Previously, several polymorphisms in TGFB1 have been identified in non-small-cell lung cancer (NSCLC), and the variants, C-509T, T869C, and G915C, have been demonstrated to associate with higher circulating levels of TGF-β1. However, little is known about the prognostic value of TGF-β1 polymorphisms in cancers. In this study, by genotyping the TGF-β1 T869C polymorphism in a total of 261 patients with NSCLC using DNA from blood lymphocytes, we first found that NSCLC patients, especially those with allele C carriers, had significantly higher serum TGF-β1 levels than healthy individuals. By using chi-square (χ²) test and Fisher's exact test, we noticed that TC/CC genotypes were positively correlated with smoking, clinical TNM stage, lymph node, and distant metastasis in NSCLC patients. Kaplan-Meier analysis showed that patients with TT genotype had a better overall survival than the allele C carriers (TC + CC). Finally, multivariate analysis confirmed histology, lymph node, and distant metastasis but not T869C polymorphism as independent prognostic factors for NSCLC. Taken together, our data, as a proof of principle, suggest that T869C polymorphism in TGFB1 may act as a genetic modifier in NSCLC progression and a promising prognostic marker of survival in NSCLC patients.

RRM1 *151A>T, RRM1 -756T>C, and RRM1 -585T>Gis associated with increased susceptibility of lung cancer in Chinese patients

Ribonucleotide reductase M1 (RRM1) is a crucial gene in DNA repair. Recent studies have shown that RRM1 expression can be a powerful predictor of survival or chemotherapy sensitivity in patients presenting with carcinomas who are treated with adjuvant gemcitabine-based chemotherapy including lung cancer. However, the relationship between the single nucleotide polymorphisms (SNP) of RRM1 and the susceptibility of lung cancer to chemotherapy has not been well addressed. We detected six tag SNPs of RRM1 genotypes in a cohort of 1007 patients with primary lung cancer and 1007 age- and sex-matched population controls using SNaPshot detection technology. Logistic regression, odds ratios (OR), and 95% confidence intervals were calculated to estimate lung cancer risk associated with SNP genotypes and haplotypes, after adjusting for case-control matching factors. Compared with the T/T and A/T genotype of RRM1 *151A>T, the A/A genotype had an increased risk for overall lung cancer (adjusted OR, 1.33). Additionally, the T/T+T/C genotypes of RRM1 -756T>C were risk factors that increased the susceptibility to lung cancer (adjusted OR 1.54, as compared with the C/C genotype). While the T/T+G/T genotypes of RRM1 -585T>G behaved as protective factors to increase the susceptibility to lung cancer (adjusted OR 0.44, as compared with the C/C genotype). In summary, this is the first study to systematically identify the relationship between the polymorphisms of RRM1 and individual susceptibility to lung cancer. It is anticipated that the RRM1 *151A>T, RRM1 -756T>C, and RRM1 -585T>G polymorphisms will improve the predictive prognosis of lung cancer sensitivity.

The relationship between RRM1 gene polymorphisms and effectiveness of gemcitabine-based first-line chemotherapy in advanced NSCLC patient

Purpose

Chemotherapy with platinum compounds and gemcitabine is frequently used in first-line treatment of advanced non-small cell lung cancer (NSCLC) patients in which tyrosine kinase inhibitors (EGFR or ALK) cannot be administered. Unfortunately, less than half of the patients achieve the benefit from chemotherapy. Gemcitabine is an analog of deoxycytidine (pyrimidine antimetabolite) with antitumor activity. The excess of deoxycytidine synthesized by RRM1 enzyme activity may be a cause of competitive displacement of gemcitabine, which reduces the efficacy of this cytostatic. The aim of this study was to determine the association between single nucleotide polymorphisms (SNPs) of the RRM1 promoter (−37C>A, −524C>T) and the effectiveness of first-line chemotherapy based on platinum compounds and gemcitabine in NSCLC patients.

Patients and methods

SNPs were determined by SNaPshot PCR^® in DNA isolated from peripheral blood of 91 NSCLC patients.

Results

The median progression-free survival (PFS) was significantly longer in carriers of AA (−37C>A) as well as CC (−524C>T) genotype of RRM1 compared to patients with other genotypes (10.5 vs 3.5 months, p = 0.0437; HR = 2.17, 95 % CI 1.02–4.62 and 10.5 vs 3.5 months, p = 0.0343; HR = 2.12, 95 % CI 1.06–4.27). In addition, the CC genotype carriers (−37C>A) showed a significant increase in the risk of shortening overall survival (OS) in comparison to patients with AA or AC genotypes (9.5 vs 18 months, p = 0.0193; HR = 2.13, 95 % CI 1.13–4.03).

Conclusions

Presence of rare AA (−37C>A) and CC (−524C>T) genotypes of the RRM1 may be favorable predictive factors for chemotherapy with platinum compounds and gemcitabine in NSCLC patients.

Phase II study of biomarker-guided neoadjuvant treatment strategy for IIIA-N2 non-small cell lung cancer based on epidermal growth factor receptor mutation status

Background

Neoadjuvant erlotinib and customized adjuvant therapy are appealing but controversial. The purpose of this study was to evaluate the role of biomarker-guided neoadjuvant treatment strategy in patients with IIIA-N2 non-small cell lung cancer (NSCLC) stratified by epidermal growth factor receptor (EGFR) mutation status.

Findings

Patients with resectable histologically documented stage IIIA-N2 NSCLC were assigned to a neoadjuvant erlotinib arm or a gemcitabine/carboplatin (GC) arm based on EGFR mutation status. The primary endpoint was response rate (RR). Secondary endpoints were progression-free survival (PFS) and overall survival (OS).

Twenty-four patients with IIIA-N2 NSCLC were enrolled in the trial from January 2008 until May 2011. The overall response rate was 41.7 % and the PFS and OS were 7.9 and 23.2 months, respectively, in overall population. The RR was 58.3 % (7/12) for the erlotinib arm with mutant EGFR and 25.0 % (3/12) for the GC arm with wild type EGFR (P = 0.18). Median PFS was 6.9 months versus 9.0 months, respectively (P = 0.071). Median OS was 14.5 months for the erlotinib arm and 28.1 months for the GC arm (P = 0.201). No unexpected toxicities were observed.

Conclusions

The primary endpoint was met and biomarker-guided neoadjuvant treatment strategy in patients with IIIA-N2 NSCLC is feasible. Erlotinib alone in neoadjuvant setting of EGFR mutant population showed an improved response but without survival benefits.

Trial registration

ClinicalTrials.gov NCT00600587 https://www.clinicaltrials.gov/ct2/show/NCT00600587?term=NCT00600587&rank=1

Electronic supplementary material

The online version of this article (doi:10.1186/s13045-015-0151-3) contains supplementary material, which is available to authorized users.

Congenic mapping and allele-specific alteration analysis of Stmm1 locus conferring resistance to early-stage chemically induced skin papillomas

Genome-wide association studies have revealed that many low-penetrance cancer susceptibility loci are located throughout the genome; however, a very limited number of genes have been identified so far. Using a forward genetics approach to map such loci in a mouse skin cancer model, we previously identified strong genetic loci conferring resistance to early-stage chemically induced skin papillomas on chromosome 7 with a large number of [(FVB/N×MSM/Ms)×FVB/N] F1 backcross mice. In this report, we describe a combination of congenic mapping and allele-specific alteration analysis of the loci on chromosome 7. We used linkage analysis and congenic mouse strains to refine the location of Stmm1 (Skin tumor modifier of MSM 1) locus within a genetic interval of about 3 cM on proximal chromosome 7. In addition, we used patterns of allele-specific imbalances in tumors from F1 backcross and N10 congenic mice to narrow down further the region of Stmm1 locus to a physical distance of about 5.4 Mb. To gain the insight into the function of Stmm1 locus, we carried out a long term BrdU labelling experiments with congenic mice containing Stmm1 locus. Interestingly, we observed a decrease of BrdU-LRCs (Label Retaining Cells) in a congenic strain heterozygous or homozygous for MSM allele of Stmm1. These results suggest that Stmm1 responsible genes may have an influence on papillomagenesis in the two-stage skin carcinogenesis by regulating epidermal quiescent stem cells.

RRM1 and RRM2 pharmacogenetics: association with phenotypes in HapMap cell lines and acute myeloid leukemia patients

BACKGROUND

Ribonucleotide reductase catalyzes an essential step in the cellular production of deoxyribonucleotide triphosphates and has been associated with clinical outcome in cancer patients receiving nucleoside analog-based chemotherapy.

MATERIALS & METHODS

In the current study, we sequenced the genes RRM1 and RRM2 in genomic DNA from HapMap cell lines with European (Utah residents with northern and western European ancestry [CEU]; n = 90) or African (Yoruba people in Ibadan, Nigeria [YRI]; n = 90) ancestry.

RESULTS

We identified 44 genetic variants including eight coding SNPs in RRM1 and 15 SNPs including one coding SNP in RRM2. RRM1 and RRM2 mRNA expression levels were significantly correlated with each other in both CEU and YRI lymphoblast cell lines, and in leukemic blasts from acute myeloid leukemia (AML) patients (AML97, n = 89; AML02, n = 187). Additionally, RRM1 expression was higher among patient features indicative of a high relapse hazard. We evaluated SNPs within the RRM1 and RRM2 genes in the HapMap lymphoblast cell lines from CEU and YRI panels for association with expression and cytarabine chemosensitivity. SNPs of potential significance were further evaluated in AML patients. RRM1 SNPs rs1042919 (which occurs in linkage disequilbrium with multiple other SNPs) and promoter SNP rs1561876 were associated with intracellular 1-β-D-arabinofuranosyl-CTP levels, response after remission induction therapy, risk of relapse and overall survival in AML patients receiving cytarabine and cladribine.

CONCLUSION

These results suggest that SNPs within ribonucleotide reductase might be helpful predictive markers of response to nucleoside analogs and should be further validated in larger cohorts.

Gene aberrations of RRM1 and RRM2B and outcome of advanced breast cancer after treatment with docetaxel with or without gemcitabine

Background

The purpose of the present study was to retrospectively evaluate whether copy number changes of the genes encoding the ribonucleotide reductase subunit M1 (RRM1) and/or subunit M2B (RRM2B) predict sensitivity to gemcitabine administered in combination with docetaxel compared to single agent docetaxel in advanced breast cancer patients.

Methods

Primary tumor samples from patients randomly assigned to gemcitabine plus docetaxel or docetaxel alone were analyzed for RRM1 and RRM2B copy number changes using Fluorescence In Situ Hybridization (FISH) technology with probes covering respectively RRM1 at 11p15.5 and a reference probe covering the centromere of chromosome 11 (CEN-11), and RRM2B at 8q22.3 and a reference probe covering the centromere of chromosome 8 (CEN-8). The assays were validated in a material of 60 normal breast samples. Time to progression (TTP) was the primary endpoint. Overall survival (OS) and response rate (RR) were secondary endpoints. Associations between RRM1/CEN-11 and/or RRM2B/CEN-8 ratios and time-to-event endpoints were analyzed by unadjusted and adjusted Cox proportional hazards regression models. Heterogeneity of treatment effects on TTP and OS according to gene status were investigated by subgroup analyses, and the Wald test was applied. All statistical tests were two-sided.

Results

FISH analysis for both RRM1 and RRM2B was successful in 251 patients. RRM1 and RRM2B aberrations (deletions and amplifications) were observed in 15.9% and 13.6% of patients, respectively. RRM1 aberrations were associated with a decreased OS in the time interval 1.5-7.4 years (hazard ratio = 1.72, 95% confidence interval = 1.05-2.79, P = 0.03). RRM2B aberrations alone or in combination with RRM1 aberrations had no prognostic impact in terms of TTP or OS. RR was not different by gene status. No significant differences were detected in TTP or OS within subgroups according to gene status and chemotherapy regimen.

Conclusions

This study demonstrated the presence of RRM1 and RRM2B copy number changes in primary breast tumor specimens. Nevertheless, we found no support of the hypothesis that aberrations of RRM1 or RRM2B, neither individually nor in combination, are associated with an altered clinical outcome following chemotherapy with gemcitabine in combination with docetaxel compared to docetaxel alone in advanced breast cancer patients.

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.

Lung cancer in women

Recent biological advances in tumor research provide clear evidence that lung cancer in females is different from that in males. These differences appear to have a direct impact on the clinical presentation, histology, and outcomes of lung cancer. Women are more likely to present with lung adenocarcinoma, tend to receive a diagnosis at an earlier age, and are more likely to be diagnosed with localized disease. Women may also be more predisposed to molecular aberrations resulting from the carcinogenic effects of tobacco, but do not appear to be more susceptible than men to developing lung cancer. The gender differences found in female lung cancer make it mandatory that gender stratification is used in clinical trials in order to improve the survival rates of patients with lung cancer.

Pharmacogenetics of chemotherapy efficacy in breast cancer

Large differences are observed in chemotherapy response between breast cancer patients, with a substantial part of this variability being explained by genetic factors. Polymorphisms in genes encoding drug-metabolizing enzymes, drug transporters and drug targets influence the pharmacokinetics and pharmacodynamics of these anticancer drugs, leading to differences in therapeutic efficacy. Pharmacogenetic investigations of breast cancer therapeutics focused on these candidate loci have been performed. This article summarizes the status of research to identify polymorphisms in genes that influence response to the chemotherapeutic agents used in breast cancer treatment and suggests future directions for this line of research. Understanding the genetic factors that predispose patients to poor treatment outcomes will help guide individualized therapeutic strategies to obtain maximal benefit.

RRM1 expression and clinical outcome of gemcitabine-containing chemotherapy for advanced non-small-cell lung cancer: a meta-analysis

BACKGROUND

The predictive value of RRM1 to therapeutic efficacy of gemicitabine-containing chemotherapy in patients with advanced non-small-cell lung cancer (NSCLC) remains disputable. This meta-analysis is performed to systematically evaluate whether RRM1 expression is associated with the clinical outcome of gemcitabine-containing regimen in advanced NSCLC.

METHODS

An electronic search was conducted using the databases Pubmed, Medline, EMBASE, Cochrane library and CNKI, from inception to May, 2011. A systemic review of the studies on the association between RRM1 expression in advanced NSCLC and clinical outcome of gemcitabine-containing regimen was performed. Pooled odds ratios (OR) for the response rate, weighted median survival and time to progression were calculated using the software Revman 5.0.

RESULTS

The search strategy identified 18 eligible studies (n=1243). Response rate to gemcitabine-containing regimen was significantly higher in patients with low/negative RRM1 (OR=0.31, 95% CI 0.21-0.45, P<0.00001). NSCLC patients with low/negative RRM1 who were treated with gemicitabine-containing regimen survived 3.94 months longer (95% CI 2.15-5.73, P<0.0001) and had longer time to progression for 2.64 months (95% CI 0.39-4.89, P=0.02) than those with high/positive RRM1.

CONCLUSIONS

Low/negative RRM1 expression in advanced NSCLC was associated with higher response rate to gemcitabine-containing regimen and better prognosis. Large phase III randomized trials are required to identify whether RRM1 detection is clinically valuable for predicting the prognosis and sensitivity to gemcitabine-containing regimen in advanced NSCLC.

Systematic evaluation of genetic variants in three biological pathways on patient survival in low-stage non-small cell lung cancer

INTRODUCTION

Studies from selected candidate genes suggest that single-nucleotide polymorphisms (SNPs) involved in glutathione metabolism, DNA repair, or inflammatory responses may affect overall survival (OS) in stages I to II or low-stage non-small cell lung cancer (LS-NSCLC); however, results are inconclusive. In this study, we took a systematic pathway-based approach to simultaneously evaluate the impact of genetic variation from these three pathways on OS after LS-NSCLC diagnosis.

METHODS

DNA from 647 patients with LS-NSCLC was genotyped for 480 SNPs (tag-SNPs) tagging 57 genes from the three candidate pathways. Associations of tag-SNPs with OS were assessed at the individual SNP and whole gene levels, adjusting for age, tumor stage, surgery type, and adjuvant therapy. The genotype combinations of the SNPs associated with OS were also estimated.

RESULTS

Among the 412 tag-SNPs that were successfully genotyped and passed quality assessments, 28 showed association with OS (p < 0.05). Two of the 28 were estimated to have less than a 20% chance of being false positives (rs3768490 in GSTM5: p = 1.32 × 10, q = 0.06; rs1729786 in ABCC4: p = 9.25 × 10, q = 0.20). Gene-based analysis suggested that in addition to GSTM5 and ABCC4, variation in two other genes, PTGS2 and GSTA2, was also associated with OS.

CONCLUSIONS

We describe further evidence that variations in genes involved in the glutathione and inflammatory response pathways are associated with OS in patients with LS-NSCLC. Further studies are warranted to verify our findings and elucidate their functional mechanisms and clinical utility leading to improved survival for patients with lung cancer.

RRM1 gene expression in peripheral blood is predictive of shorter survival in Chinese patients with advanced non-small-cell lung cancer treated by gemcitabine and platinum

OBJECTIVE

To evaluate the predictive values of gene expressions of ribonucleotide reductase M1 (RRM1) and breast cancer susceptibility gene 1 (BRCA1) in peripheral blood from Chinese patients with non-small-cell lung cancer (NSCLC) treated with gemcitabine plus platinum.

METHODS

Forty Chinese patients with advanced NSCLC were recruited and received gemcitabine 1 200 mg/m(2) on Days 1 and 8 plus carboplatin AUC 5 on Day 1. RRM1 and BRCA1 expression levels in peripheral blood were detected by quantitative reverse transcription-polymerase chain reaction (RT-PCR). Kaplan-Meier survival curve and log-rank test were performed to evaluate the correlation between gene expression and overall survival for these subjects.

RESULTS

No correlation was observed between gene expression of RRM1 and that of BRCA1 (P>0.05), but there was a strong correlation between the expression of RRM1 and the response to chemotherapy (P=0.003). Subjects with low RRM1 expression levels in peripheral blood had longer survival time than those with high RRM1 expression levels (16.95 vs. 12.76 months, log-rank 3.989, P=0.046). However, no significant association between BRCA1 expression levels and survival time was found (16.80 vs. 13.77 months, log-rank 0.830, P=0.362).

CONCLUSIONS

Patients with low RRM1 expression levels in peripheral blood have a greater response to chemotherapy and longer survival time. Advanced NSCLC patients with low RRM1 expression levels may benefit from gemcitabine plus platinum therapy. RRM1 mRNA expression in peripheral blood could be used to predict the prognosis of NSCLC treated by gemcitabine and platinum.

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.

[Advances of drug resistance marker of gemcitabine for non-small cell lung cancer]

随着药物基因组学、药物遗传学的发展，基因指导下个体化治疗成为提高非小细胞肺癌（non-small cell lung cancer, NSCLC）化疗疗效的有效途径之一。确定药物的相关预测性分子标志物从而指导临床治疗、提高疗效被广泛关注。吉西他滨是目前NSCLC常用化疗药物之一，本文主要阐述了近年来吉西他滨药物耐药相关基因在NSCLC个体化治疗方面的研究进展。

Ethnic differences in the metabolism, toxicology and efficacy of three anticancer drugs

INTRODUCTION

Large inter-individual and inter-ethnic differences are observed in efficacies and toxicities of medical drugs. To improve the predictability of these differences, pharmacogenetic information has been applied to clinical situations. Expanding pharmacogenetic information would be a valuable tool to the medical community as well as the patient to fulfill the promise of personalized anticancer drug therapy.

AREAS COVERED

This review highlights genetic polymorphisms and ethnic differences of genes, UGT1As, CYP3A4, CES1As, ABCB1, ABCC2, ABCG2, SLCO1B1, CDA and CYP2D6, involved in metabolism and disposition of three anticancer drugs: irinotecan, gemcitabine and tamoxifen.

EXPERT OPINION

Recent pharmacogenetic studies have successfully identified distinct ethnic differences in genetic polymorphisms that are potentially involved in efficacies and toxicities of anticancer drugs. This achievement has led to personalized irinotecan therapy, reflecting ethnic differences in UGT1A1 genotypes, and possible benefits of genetic testing have also been suggested for gemcitabine and tamoxifen therapy, which still requires further validation. The ultimate goal for patients is a high rate or even perfect prediction of efficacies and toxicities of anticancer drugs in each ethnic population. For this challenge, more clinical studies combined with comprehensive omics approaches are necessary to further advance the field.

Molecular mechanism of the schedule-dependent synergistic interaction in EGFR-mutant non-small cell lung cancer cell lines treated with paclitaxel and gefitinib

Background

Chemotherapy combined concurrently with TKIs produced a negative interaction and failed to improve survival when compared with chemotherapy or TKIs alone in the treatment of non-small cell lung cancer (NSCLC). The present study investigated the sequence-dependent interaction between paclitaxel and gefitinib and clarified the underlying mechanism.

Methods

The effects on cell proliferation, EGFR signaling pathway, and TGFα expression were evaluated in a panel of human NSCLC cell lines harboring EGFR mutations with three different combination sequences: sequential treatment with paclitaxel followed by gefitinib (T→G), sequential treatment with gefitinib followed by paclitaxel (G→T), or concomitant treatment (T + G).

Results

The sequence-dependent anti-proliferative effects differed between EGFR-TKI-sensitive and -resistant cell lines carrying EGFR mutations. A synergistic anti-proliferative activity was obtained with paclitaxel treatment followed by gefitinib in all cell lines, with mean CI values of 0.63 in Hcc827, 0.54 in PC-9, 0.81 in PC-9/GR, and 0.77 in H1650 cells for the T→G sequence. The mean CI values for the G→T sequence were 1.29 in Hcc827, 1.16 in PC-9, 1.52 in PC-9/GR, and 1.5 in H1650 cells. The mean CI values for T+G concomitant treatment were 0.88 in Hcc827, 0.91 in PC-9, 1.05 in PC-9/GR, and 1.18 in H1650 cells. Paclitaxel produced a dose-dependent increase in EGFR phosphorylation. Paclitaxel significantly increased EGFR phosphorylation compared with that in untreated controls (mean differences: +50% in Hcc827, + 56% in PC-9, + 39% in PC-9/GR, and + 69% in H1650 cells; p < 0.05). The T→G sequence produced significantly greater inhibition of EGFR phosphorylation compared with the opposite sequence (mean differences: -58% in Hcc827, -38% in PC-9, -35% in PC-9/GR, and -30% in H1650 cells; p < 0.05). Addition of a neutralizing anti-TGFα antibody abolished paclitaxel-induced activation of the EGFR pathway in PC-9 and H1650 cells. Sequence-dependent TGFα expression and release are responsible for the sequence-dependent EGFR pathway modulation.

Conclusion

The data suggest that the sequence of paclitaxel followed by gefitinib is an appropriate treatment combination for NSCLC cell lines harboring EGFR mutations. Our results provide molecular evidence to support clinical treatment strategies for patients with lung cancer.

Adjuvant cisplatin-based chemotherapy for resected NSCLC: one size fits all?

The standard of care for resected stage II - IIIA non-small-cell lung cancer includes adjuvant chemotherapy based on the results of randomized trials using cisplatin regimens. A recent meta-analysis (Lung Adjuvant Cisplatin Evaluation) showed no survival benefit for this modality in stage IB disease. Therefore, the role for stage IB disease remains controversial. The Lung Adjuvant Cisplatin Evaluation meta-analysis, which is based on pooled data of five randomized trials, has shown a 5.3% absolute survival benefit at 5 years. However, long-term results of the International Adjuvant Lung Cancer Trial evaluating adjuvant cisplatin-based chemotherapy in resected non-small-cell lung cancer indicated a possible late adjuvant chemotherapy-related over-mortality. Tumor stage currently is the benchmark standard use for identifying patients who would benefit from adjuvant treatment. In the knowledge of late adjuvant chemotherapy-related over-mortality it is therefore critical to identify subsets of patients who would or would never benefit from adjuvant cisplatin. This review will discuss the extent to which individualized adjuvant treatment can be provided.

The ribonucleotide reductase large subunit (RRM1) as a predictive factor in patients with cancer

The large subunit of human ribonucleotide reductase, RRM1, is involved in the regulation of cell proliferation, cell migration, tumour and metastasis development, and the synthesis of deoxyribonucleotides for DNA synthesis. It is also a cellular target for the chemotherapeutic agent, gemcitabine. RRM1 has been studied in a large number of patients with different types of cancer, such as non-small-cell lung cancer, pancreatic cancer, breast cancer, and biliary tract cancer, to establish its prognostic or predictive value when patients were treated with gemcitabine, and mRNA expression and genetic variants as determined by genotyping have in some cases been associated with clinical outcome of patients with cancer. Here, we review preclinical and clinical studies of RRM1 assessment and discuss the further steps in the development of this clinically pertinent biomarker.