Expression of ERCC1 and class III beta-tubulin in non-small cell lung cancer patients treated with carboplatin and paclitaxel

Genotyping, in silico screening and molecular dynamics simulation of SNPs of MGMT and ERCC1 gene in lung cancer patients treated with platinum-based doublet chemotherapy

Lung cancer, the leading cause of death worldwide, arises from an intricate combination of genetic and environmental factors. Genetic variations can influence the chemotherapeutic response of lung cancer patients in DNA repair genes. This study examines the response to platinum-based drugs among lung cancer patients of North Indian descent who possess genetic variations in the MGMT and ERCC1 genes. P CR-RFLP method was used for genotypic analysis. MedCalc statistical software was used to calculate odds ratios and Median Survival Time (MST). GROMACS software was used to perform Molecular dynamic simulation. ADCC Patients revealed a significant association with MGMT in the heterozygous genotype (HR= 1.56, p=0.02) and also with ERCC1 in both mutant and combined variants (HR= 1.25, p=0.01; HR=0.78, p=0.03). SQCC subjects harbouring ERCC1 polymorphism also reported a 2-fold increase in hazard ratio and a corresponding decrease in survival time for heterozygous and combined variants (HR= 2.55, p=0.02; HR 2.33, p=0.01, respectively). MD simulation results demonstrate a lower RMSD, stable radius of gyration, and lower RMSF, indicating the mutated MGMT protein is more stable than the wild. Further, the docking score for DNA-Wild and DNA-L84F mutants are -201.6 and -131.8, respectively. MD Simulation of the complexes further validated the results. Our study concludes that MGMT and ERCC1 polymorphisms are associated with decreased overall survival. Further, computational analysis of MGMT (rs12917) polymorphism revealed that mutated MGMT cannot bind properly to the DNA and hence cannot properly repair DNA, resulting in lower overall survival.Communicated by Ramaswamy H. Sarma.

Personalized Prescription of Chemotherapy Based on Assessment of mRNA Expression of BRCA1, RRM1, ERCC1, TOP1, TOP2α, TUBβ3, TYMS, and GSTP1 Genes in Tumors Compared to Standard Chemotherapy in the Treatment of Non-Small-Cell Lung Cancer

Objectives: A growing body of evidence suggests the important role of chemosensitive gene expression in the prognosis of patients with lung cancer. However, studies on combined gene expression assessments for personalized prescriptions of chemotherapy regimens in patients have not yet been conducted. The aim of this work was to conduct a prospective study on the appointment of personalized chemotherapy in patients with non-small-cell lung cancer. Materials and methods: The present study analyzed 85 patients with lung cancer (stage IIB-IIIB). Within this group, 48 patients received individualized chemotherapy, and 37 patients received classical chemotherapy. In the individualized chemotherapy group, the mRNA expression levels of ERCC1, RRM1, TUBB3, TYMS, TOP1, TOP2α, BRCA1, and GSTP1 in lung tissues were measured by quantitative real-time PCR (qPCR), and an individual chemotherapy regimen was developed for each patient according to the results. Patients in the classical chemotherapy group received the vinorelbine/carboplatin regimen. Survival analyses were performed using the Kaplan−Meier method. Prognostic factors of metastasis-free survival (MFS) and overall survival (OS) of patients were identified via Cox’s proportional hazards regression model. Results: MFS and OS were significantly better in the personalized chemotherapy group compared to the classic chemotherapy group (MFS, 46.22 vs. 22.9 months, p = 0.05; OS, 58.6 vs. 26.9 months, p < 0.0001). Importantly, the best metastasis-free survival rates in the group with personalized ACT were achieved in patients treated with the paclitaxel/carboplatin regimen. Based on an assessment of chemosensitivity gene expression in the tumors, the classical chemotherapy strategy also increased the risk of death (HR = 14.82; 95% CI: 3.33−65.86; p < 0.000) but not metastasis (HR = 1.95; 95% CI: 0.96−3.98; p = 0.06) compared to the group of patients with chemotherapy. Conclusions: The use of combined ERCC1, RRM1, TUBB3, TYMS, TOP1, TOP2α, BRCA1, and GSTP1 gene expression results for personalized chemotherapy can improve treatment efficacy and reduce unnecessary toxicity.

Analysis of SPARC and TUBB3 as predictors for prognosis in esophageal squamous cell carcinoma receiving nab-paclitaxel plus cisplatin neoadjuvant chemotherapy: a prospective study

PURPOSE

The purpose of the study is to evaluate the predictive efficacy of secreted protein, acidic and rich in cysteine (SPARC) and the class III β-tubulin (β-tubulin III, TUBB3) in predicting therapeutic effect in patients with locally advanced esophageal squamous cell carcinoma(ESCC) who received nab-paclitaxel plus cisplatin neoadjuvant chemotherapy(CT) followed by surgery.

METHODS

Patients with stage II to III esophageal squamous cell carcinoma of different stages are recruited. The tumor biopsy tissues prior treatment from enrolled patients were examined by SPARC and TUBB3 immunohistochemistry (IHC). Correlations between SPARC/TUBB3 expression and response to chemotherapy and long-term survival in patients received surgical resection was analyzed.

RESULTS

A total of 35 patients with stage II to III esophageal squamous cell carcinoma were enrolled. Of the 35 enrolled patients, 30 successfully completed neoadjuvant chemotherapy and underwent R0 resection, 3 refused surgery after chemotherapy, and 2 failed to undergo radical surgery after chemotherapy. Out of patients undergoing surgery, pathological complete response (pCR) was achieved in 6 patients (6/30, 20%). The 1, 2 and 5-year disease free survival (DFS) rates were 70.0%, 36.6% and 33.3%, respectively. The 1, 2 and 5-year overall survival (OS) rates were 83.3%, 63.3% and 36.6%, respectively. SPARC and TUBB3 IHC was performed on the tumor biopsy tissues which were obtained from patients before treatment. Correlation between SPARC/TUBB3 expression and long-term survival in patients was studied. Both the median DFS and OS between SPARC negative samples and SPARC positive staining samples have no statistical difference. However, the median DFS and OS in TUBB3 negative patients was better than those in TUBB3 positive patients (p = 0.002 for DFS, p = 0.001 for OS). In addition, patients with pCR had longer OS and DFS time than those without pCR.COX regression analysis showed that TUBB3 prior treatment and pCR were independent prognostic factors in ESCC patients undergoing sequential surgery after preoperative chemotherapy.

CONCLUSIONS

TUBB3 negative expression prior treatment and pCR may indicate a better prognosis for stage II and III ESCC patients after nab-paclitaxel plus cisplatin neoadjuvant chemotherapy following radical esophagectomy.

Quantification and expert evaluation of evidence for chemopredictive biomarkers to personalize cancer treatment

Predictive biomarkers have the potential to facilitate cancer precision medicine by guiding the optimal choice of therapies for patients. However, clinicians are faced with an enormous volume of often-contradictory evidence regarding the therapeutic context of chemopredictive biomarkers.

We extensively surveyed public literature to systematically review the predictive effect of 7 biomarkers claimed to predict response to various chemotherapy drugs: ERCC1-platinums, RRM1-gemcitabine, TYMS-5-fluorouracil/Capecitabine, TUBB3-taxanes, MGMT-temozolomide, TOP1-irinotecan/topotecan, and TOP2A-anthracyclines. We focused on studies that investigated changes in gene or protein expression as predictors of drug sensitivity or resistance. We considered an evidence framework that ranked studies from high level I evidence for randomized controlled trials to low level IV evidence for pre-clinical studies and patient case studies.

We found that further in-depth analysis will be required to explore methodological issues, inconsistencies between studies, and tumor specific effects present even within high evidence level studies. Some of these nuances will lend themselves to automation, others will require manual curation. However, the comprehensive cataloging and analysis of dispersed public data utilizing an evidence framework provides a high level perspective on clinical actionability of these protein biomarkers. This framework and perspective will ultimately facilitate clinical trial design as well as therapeutic decision-making for individual patients.

Expression of ERCC1 and Class III β-Tubulin in Resected Non-Small Cell Lung Cancer and its Correlation with Platinum-Based Adjuvant Chemotherapy

Objective

To explore the relationship between the expression of excision repair cross-complementation group 1 (ERCC1) and class III β-tubulin and the clinical characteristics and overall survival of patients with non-small cell lung cancer (NSCLC).

Methods

Immunohistochemical analysis was used to determine the protein expression of ERCC1 and class III β-tubulin in 160 completely resected NSCLC primary tumor samples, 50 of which were paired with adjacent normal tissue samples and another 40 benign lung lesion tissue samples as controls. Clinical data at baseline, disease-free survival and overall survival were also collected. Univariate and multivariate Cox models were used to analyze the risk factors.

Results

In 160 tumor samples, the ERCC1 and class III β-tubulin positive rates obtained with immunohistochemistry were 46.9% and 49.4%, respectively. Both biomarkers had a higher positive rate in male patients. For patients who did not receive adjuvant chemotherapy, ERCC1 positivity was associated with longer survival (median survival time 73 vs 53 months, p=0.041), while in patients treated with platinum chemotherapy, ERCC1 positivity tended to be associated with poor survival (median survival time 41 vs 54 months, p=0.014). Class III β-tubulin positivity was also associated with poor survival (median survival time 38 vs 58 months, p<0.001), but had no influence on the survival of patients who did not receive adjuvant chemotherapy.

Conclusions

ERCC1 and class III β-tubulin could be important survival predictors for completely resected NSCLC patients treated with adjuvant chemotherapy. Further prospective studies need to be performed to test this hypothesis in Chinese patients.

Prevalence of βIII-tubulin (TUBB3) expression in human normal tissues and cancers

Microtubules are multifunctional cytoskeletal proteins that are involved in crucial cellular roles including maintenance of cell shape, intracellular transport, meiosis, and mitosis. Class III beta-tubulin (βIII-tubulin, also known as TUBB3) is a microtubule protein, normally expressed in cells of neuronal origin. Its expression was also reported in various other tumor types, such as several types of lung cancer, ovarian cancer, and esophageal cancer. TUBB3 is of clinical relevance as overexpression has been linked to poor response to microtubule-targeting anti-cancer drugs such as taxanes. To systematically investigate the epidemiology of TUBB3 expression in normal and neoplastic tissues, we used tissue microarrays for analyzing the immunohistochemically detectable expression of TUBB3 in 3911 tissue samples from 100 different tumor categories and 76 different normal tissue types. At least 1 tumor with weak expression could be found in 93 of 100 (93%) different tumor types, and all these 93 entities also had at least 1 tumor with strong positivity. In normal tissues, a particularly strong expression was found in neurons of the brain, endothelium of blood vessels, fibroblasts, spermatogenic cells, stroma cells, endocrine cells, and acidophilic cells of the pituitary gland. In tumors, strong TUBB3 expression was most frequently found in various brain tumors (85%-100%), lung cancer (35%-80%), pancreatic adenocarcinoma (50%), renal cell carcinoma (15%-80%), and malignant melanoma (77%). In summary, these results identify a broad spectrum of cancers that can at least sporadically express TUBB3. Testing of TUBB3 in cancer types eligible for taxane-based therapies could be helpful to identify patients who might best benefit from this treatment.

Expression of ERCC1, RRM1, TUBB3 in correlation with apoptosis repressor ARC, DNA mismatch repair proteins and p53 in liver metastasis of colorectal cancer

Liver metastasis in colorectal cancer is common and the primary treatment is chemotherapy. To date, there is no routinely used test in clinical practice to predict the effectiveness of conventional chemotherapy. Therefore, biomarkers with predictive value for conventional chemotherapy would be of considerable benefit in treatment planning. We analysed three proteins [excision repair cross-complementing 1 (ERCC1), ribonucleoside-diphosphate reductase 1 (RRM1) and class III β-tubulin (TUBB3)] in colorectal cancer liver metastasis. We used tissue microarray slides with 101 liver metastasis samples, stained for ERCC1, RRM1 and TUBB3 and established scoring systems (fitted for tissue microarray) for each protein. In statistical analysis, we compared the expression of ERCC1, RRM1 and TUBB3 to mismatch proteins (MLH1, MSH2, MSH6 and PMS2), p53 and to apoptosis repressor protein (ARC). Statistically significant correlations were found between ERCC1, TUBB3 and MLH1, MSH2 and RRM1 and MSH2, MSH6. Noteworthy, our analysis revealed a strong significant correlation between cytoplasmic ARC expression and RRM1, TUBB3 (p=0.000 and p=0.001, respectively), implying an additional role of TUBB3 and RRM1 not only in therapy resistance, but also in the apoptotic machinery. Our data strengthens the importance of ERCC1, TUBB3 and RRM1 in the prediction of chemotherapy effectiveness and suggest new functional connections in DNA repair, microtubule network and apoptotic signaling (i.e. ARC protein). In conclusion, we showed the importance and need of predictive biomarkers in metastasized colorectal cancer and pointed out the relevance not only of single predictive markers but also of their interactions with other known and newly explored relations between different signaling pathways.

An Emerging Role for Tubulin Isotypes in Modulating Cancer Biology and Chemotherapy Resistance

Tubulin proteins, as components of the microtubule cytoskeleton perform critical cellular functions throughout all phases of the cell cycle. Altered tubulin isotype composition of microtubules is emerging as a feature of aggressive and treatment refractory cancers. Emerging evidence highlighting a role for tubulin isotypes in differentially influencing microtubule behaviour and broader functional networks within cells is illuminating a complex role for tubulin isotypes regulating cancer biology and chemotherapy resistance. This review focuses on the role of different tubulin isotypes in microtubule dynamics as well as in oncogenic changes that provide a survival or proliferative advantage to cancer cells within the tumour microenvironment and during metastatic processes. Consideration of the role of tubulin isotypes beyond their structural function will be essential to improving the current clinical use of tubulin-targeted chemotherapy agents and informing the development of more effective cancer therapies.

Evaluating the Prognostic Value of ERCC1 and Thymidylate Synthase Expression and the Epidermal Growth Factor Receptor Mutation Status in Adenocarcinoma Non-Small-Cell Lung Cancer

The present study evaluated the prognostic value of the epidermal growth factor receptor (EGFR) mutation status, and excision repair cross-complementation group 1 (ERCC1) and thymidylate synthase (TS) expression following intercalated tyrosine kinase inhibitor (TKI) therapy and platinum- and pemetrexed-based chemotherapies (subsequent second-line treatment) for patients with adenocarcinoma non-small-cell lung cancer (AC-NSCLC). In total, 131 patients with AC-NSCLC were enrolled. The EGFR mutation status and ERCC1 and TS expression were evaluated through direct DNA sequencing and immunohistochemical analyses, respectively. The EGFR mutation status and ERCC1 and TS expression were the significant predictors of clinical outcomes. The EGFR mutation status was the main outcome predictor for overall survival (OS) benefits in the overall population. Further exploratory ERCC1 and TS expression analyses were conducted to provide additional insights. Low TS expression was predictive of improved OS of patients with negative EGFR-mutated advanced AC-NSCLC, whereas high ERCC1 expression resulted in poor OS in patients with positive EGFR-mutated advanced AC-NSCLC. TS and ERCC1 expression levels were effective prognostic factors for negative and positive EGFR-mutated AC-NSCLC, respectively. In conclusion, the present results indicate that the EGFR mutation status and TS and ERCC1 expression can be used as the predictors of OS after subsequent second-line treatments for AC-NSCLC.

Development and Validation of an ERCC1 Immunohistochemistry Assay for Solid Tumors

CONTEXT

- Excision repair cross-complementation 1 (ERCC1) is a key enzyme in nuclear excision repair pathway and has a critical role in helping remove DNA adducts caused by cross-linking agents, such as platinum-containing cancer chemotherapies and other DNA-damaging therapeutic modalities. ERCC1 expression, evaluated by techniques such as immunohistochemistry, has been associated with clinical response; ERCC1⁺ tumors are more resistant to cisplatin treatment than are ERCC1^- tumors. Although several immunohistochemistry, anti-ERCC1 antibodies are available, the 8F1 clone, in particular, has been used in many studies. Recent evidence has suggested that the 8F1 antibody cross-reacts with at least one other protein, raising concerns about the specificity of this clone.

OBJECTIVE

- To design an immunohistochemistry assay to detect ERCC1 levels that show dynamic range and consistent analytic performance.

DESIGN

- Two different primary antibodies to ERCC1, clones 4F9 and D6G6, were evaluated on formalin-fixed, paraffin-embedded tissue. We then performed a fit-for-purpose assay validation with the 4F9 clone, which included sensitivity assessment across several solid tumor types and evaluation of analytic parameters, such as precision and reproducibility.

RESULTS

- The 4F9 clone was consistently superior to the D6G6 clone in the optimization phase. A range of expression was seen in ovarian, head and neck, non-small cell lung, and esophageal cancer samples when tested with the 4F9 clone. The antibody showed acceptable reproducibility (31.02%) and precision (16.06%).

CONCLUSIONS

- This assay can be used to assess ERCC1 levels during clinical studies of patient tumors from a variety of tumor types.

Comprehensive Biomarkers for Personalized Treatment in Pulmonary Large Cell Neuroendocrine Carcinoma: A Comparative Analysis With Adenocarcinoma

BACKGROUND

The prognosis for patients with large cell neuroendocrine carcinoma (LCNEC) of the lung is extremely poor, and optimal treatment strategies have not yet been established. To improve prognoses in patients with LCNEC, this study analyzed immunohistochemical expression and gene mutations of several known molecular targets in LCNECs and compared the expression levels of these targets with those in lung adenocarcinomas.

METHODS

Twenty-six patients with primary LCNEC and 40 patients with adenocarcinoma were analyzed. Excision repair cross-complementation group 1 (ERCC1), class III β-tubulin, topoisomerase I, topoisomerase II, epidermal growth factor receptor (EGFR)-L858R, and somatostatin receptor expression were evaluated by immunohistochemistry, and EGFR mutations were evaluated using direct DNA sequencing and the Scorpion-amplified refractory mutation system.

RESULTS

In patients with LCNEC and adenocarcinoma, positive rates of topoisomerase I, topoisomerase II, ERCC1, class III β-tubulin, EGFR-L858R, and somatostatin were 100.0% and 100.0%, 65.4% and 15.0% (p < 0.0001), 42.3% and 17.5% (p = 0.0462), 46.2% and 62.5%, 0.0% and 20.0% (p = 0.0182), and 50.0% and 5.0% (p < 0.0001), respectively. The frequencies of EGFR mutations were 0.0% and 37.5% in LCNEC and adenocarcinoma (p = 0.0002), respectively. Five-year overall survival rates were 64% in LCNEC and 91% in adenocarcinoma in stage I (p = 0.0132). Multivariate analysis showed that LCNEC histologic type was an independent prognostic factor in stage I.

CONCLUSIONS

LCNEC showed overexpression of topoisomerase II, somatostatin, and ERCC1. These findings suggested that it was possible to have good response to treatment with etoposide and octreotide and that LCNEC may be resistant to platinum-based therapy compared with adenocarcinoma. EGFR mutations were not observed in LCNEC. These results may indicate a favorable response to adjuvant treatments that are not typically prescribed for non-small cell lung cancer.

Expression of Ribonucleotide Reductase Subunit-2 and Thymidylate Synthase Correlates with Poor Prognosis in Patients with Resected Stages I-III Non-Small Cell Lung Cancer

Biomarkers can help to identify patients with early-stages or locally advanced non-small cell lung cancer (NSCLC) who have high risk of relapse and poor prognosis. To correlate the expression of seven biomarkers involved in DNA synthesis and repair and in cell division with clinical outcome, we consecutively collected 82 tumour tissues from radically resected NSCLC patients. The following biomarkers were investigated using IHC and qRT-PCR: excision repair cross-complementation group 1 (ERCC1), breast cancer 1 (BRCA1), ribonucleotide reductase subunits M1 and M2 (RRM1 and RRM2), subunit p53R2, thymidylate synthase (TS), and class III beta-tubulin (TUBB3). Gene expression levels were also validated in an available NSCLC microarray dataset. Multivariate analysis identified the protein overexpression of RRM2 and TS as independent prognostic factors of shorter overall survival (OS). Kaplan-Meier analysis showed a trend in shorter OS for patients with RRM2, TS, and ERCC1, BRCA1 overexpressed tumours. For all of the biomarkers except TUBB3, the OS trends relative to the gene expression levels were in agreement with those relative to the protein expression levels. The NSCLC microarray dataset showed RRM2 and TS as biomarkers significantly associated with OS. This study suggests that high expression levels of RRM2 and TS might be negative prognostic factors for resected NSCLC patients.

EGFR and K-RAS mutations and ERCC1, TUBB3, TYMS, RRM1 and EGFR mRNA expression in non-small cell lung cancer: Correlation with clinical response to gefitinib or chemotherapy

Personalizing medicines has refined the traditional treatments for non-small-cell lung cancer (NSCLC). In the present study, efforts towards personalizing delivery of care based on the status of EGFR and K-RAS mutations, and mRNA expression levels of ERCC1, TUBB3, TYMS, RRM1 and EGFR by choosing appropriate treatments for 52 patients with NSCLC were discussed. Among these 52 NSCLC patients, there were 14 patients treated with gefitinib. Ten patients with EGFR exon 21 point mutations or exon 19 deletions had better treatment outcomes following gefitinib treatment (71.4%). There were 38 patients treated with platinum-based chemotherapy. Docetaxel-platinum based chemotherapy was chosen as the first-line treatment when the patients had low or median ERCC1/TUBB3 expression and gemcitabine-platinum based chemotherapy was chosen when the patients had low or median ERCC1/RRM1 expression. In total, 26 cases had mRNA expression levels of ERCC1/TUBB3 or ERCC1/RRM1 that could be used to predict the treatment outcomes of chemotherapy (68.4%). The present results indicated that the mutation status of EGFR, as well as the mRNA expression levels of ERCC1, TUBB3 and RRM1, could be used as predictors of the response to gefitinib or chemotherapy.

Prognostic significance of the mRNA expression of ERCC1, RRM1, TUBB3 and TYMS genes in patients with non-small cell lung cancer

The present study aimed to investigate the prognostic value of excision repair cross-complementing 1 (ERCC1), ribonucleotide reductase subunit M1 (RRM1), class III β-tubulin (TUBB3) and thymidylate synthase (TYMS) in patients with non-small cell lung cancer (NSCLC) receiving platinum-based adjuvant chemotherapy. The mRNA expression of these genes was assessed in 72 tumor tissue samples obtained following surgery, using multiplex branched-DNA technology. Subsequent to surgery, all 72 patients with NSCLC were treated with platinum-based chemotherapy. The expression of these five genes was analyzed and the correlation with clinical characteristics and patient survival was investigated. Among the 72 samples, the incidence rate of mRNA expression of ERCC1 was 38.9% (28/72), RRM1 was 55.6% (40/72), TUBB3 was 47.2% (34/72) and TYMS was 62.5% (45/72). The incidence rate of ERCC1 expression in adenocarcinoma (34.2%) was significantly lower than that in non-adenocarcinoma (44.1%; P<0.05). Furthermore, the incidence rates of TYMS and TUBB3 expression in the high-median differentiation tissue samples were significantly lower than those in the low differentiation tissue samples (P<0.05). When the correlation of gene expression and patient survival was analyzed, high expression of ERCC1, RRM1, TUBB3 or TYMS was found to be associated with poor prognosis (P<0.001, P=0.001, P=0.001 and P=0.001, respectively). ERCC1, RRM1, TUBB3 and TYMS are key factors involved in survival following surgical treatment in patients with NSCLC. The mRNA expression of these genes may have prognostic value for patients with NSCLC treated with platinum-based chemotherapy.

Synergistic activity of combination therapy with PEGylated pemetrexed and gemcitabine for an effective cancer treatment

Combination therapy in cancer is now opted as a potential therapeutic strategy for cancer treatment. However, effective delivery of drugs in combination at the tumor site is marred by low bioavailability and systemic toxicity of individual drugs. Polymer therapeutics is indeed an upcoming approach for the combinational drug delivery in favor of better cancer management. Hence, the objective of our investigation was to develop a dual drug PEGylated system that carries two chemotherapeutic drugs simultaneously for effective treatment of cancer. In this regard, we have synthesized Pem-PEG-Gem, wherein pemetrexed (Pem) and gemcitabine (Gem) are conjugated to a heterobifunctional polyethylene glycol (PEG) polymer for the effective treatment of Non-Small Cell Lung Cancer (NSCLC). Our results demonstrate enhanced bioavailability of the individual drugs in Pem-PEG-Gem in comparison with the drugs in their native form. The developed Pem-PEG-Gem showed enhanced cell death with respect to their native counterparts when treated singly or in combination against NSCLC cells. This might be attributed to better cellular internalization through the process of macropinocytosis and synergistic cytotoxic action of Pem-PEG-Gem in NSCLC cells. Hence, we propose the above dual drug based polymer therapeutic approach suitable for better clinical application in the treatment of NSCLC.

Class III β-tubulin in normal and cancer tissues

Microtubules are polymeric structures composed of tubulin subunits. Each subunit consists of a heterodimer of α- and β-tubulin. At least seven β-tubulin isotypes, or classes, have been identified in human cells, and constitutive isotype expression appears to be tissue specific. Class III β-tubulin (βIII-tubulin) expression is normally confined to testes and tissues derived from neural cristae. However, its expression can be induced in other tissues, both normal and neoplastic, subjected to a toxic microenvironment characterized by hypoxia and poor nutrient supply. In this review, we will summarize the mechanisms underlying βIII-tubulin constitutive and induced expression. We will also illustrate its capacity to serve as a biomarker of neural commitment in normal tissues and as a pure prognostic biomarker in cancer patients.

Use of TUBB3 for patient stratification and prognosis in lung cancer

SUMMARY 

Microtubules play a crucial role in the eukaryote replicative cell machinery and antimicrotubule drugs such as vinca alkaloids and taxanes are important drugs in the treatment of several solid tumors. TUBB3 has in retrospective studies shown to be of significance with regard to outcome in NSCLC patients treated with anti-microtubule drugs. However, it is still controversial whether or not TUBB3 has a prognostic or a predictive value. This review provides an overview of preclinical and clinical studies that have presented data on the role of TUBB3 in NSCLC.

Emerging microtubule targets in glioma therapy

Major advances in the genomics and epigenomics of diffuse gliomas and glioblastoma to date have not been translated into effective therapy, necessitating pursuit of alternative treatment approaches for these therapeutically challenging tumors. Current knowledge of microtubules in cancer and the development of new microtubule-based treatment strategies for high-grade gliomas are the topic in this review article. Discussed are cellular, molecular, and pharmacologic aspects of the microtubule cytoskeleton underlying mitosis and interactions with other cellular partners involved in cell cycle progression, directional cell migration, and tumor invasion. Special focus is placed on (1) the aberrant overexpression of βIII-tubulin, a survival factor associated with hypoxic tumor microenvironment and dynamic instability of microtubules; (2) the ectopic overexpression of γ-tubulin, which in addition to its conventional role as a microtubule-nucleating protein has recently emerged as a transcription factor interacting with oncogenes and kinases; (3) the microtubule-severing ATPase spastin and its emerging role in cell motility of glioblastoma cells; and (4) the modulating role of posttranslational modifications of tubulin in the context of interaction of microtubules with motor proteins. Specific antineoplastic strategies discussed include downregulation of targeted molecules aimed at achieving a sensitization effect on currently used mainstay therapies. The potential role of new classes of tubulin-binding agents and ATPase inhibitors is also examined. Understanding the cellular and molecular mechanisms underpinning the distinct behaviors of microtubules in glioma tumorigenesis and drug resistance is key to the discovery of novel molecular targets that will fundamentally change the prognostic outlook of patients with diffuse high-grade gliomas.

Serpin b3 is associated with poor survival after chemotherapy and is a potential novel predictive biomarker in advanced non-small-cell lung cancer

INTRODUCTION

In a previous biomarker discovery project using gene-expression profiling we identified Serpin B3 (SB3) as a predictor of resistance to platinum doublet chemotherapy (PtC) in non-small-cell lung cancer (NSCLC). This independent prospective study was designed to confirm the predictive utility of SB3.

METHODS

SB3 immunohistochemistry was scored by previously validated criteria (score 0 = negative, score 1 = 1%-10% tumor cells positive, score 2 = 11%-50% tumor cells positive, and score 3 = >50% tumor cell positive) in 197 patients with stage IV NSCLC treated with PtC. This provided 80% power to detect a median survival increase from 150 days in patients with an SB3 immunohistochemistry score of 2 or more to 300 days in those with an SB3 score of 0 or 1.

RESULTS

Thirty-six percent of NSCLCs stained positive for SB3. Median survival for SB3 negative/score 0 was 332 days, SB3 positive/score 1 was 268 days, and SB3 positive/score 2 or 3 was 120 days (p = 0.004). Cox proportional hazards analysis demonstrated that SB3 positivity is an independent predictor of survival (hazard ratio = 1.87; 95% confidence interval, 1.29-2.71; p = 0.001).The disease control rate in SB3 score 0, 1 = 65%, and score of 2 or more = 20 % (p = 0.002), with median survival 306 days (score 0, 1) versus 120 days (score ≥ 2, hazard ratio= 1.71; 95% confidence interval. 1.14-3.10; p = 0.002).

CONCLUSIONS

SB3-positive immunohistochemistry score of 2 or more (>10% tumor cells positive) identifies a subgroup of patients with stage IV NSCLC who have a poor survival (median 120 days) when treated with PtC, similar to that estimated for untreated or chemo-refractory stage IV NSCLC. Further prospective qualification using biospecimens from randomized studies is needed, but SB3 seems to be a useful biomarker that identifies a highly resistant subgroup in whom PtC should be avoided.

Combination of microtubule associated protein-tau and β-tubulin III predicts chemosensitivity of paclitaxel in patients with advanced gastric cancer

AIM

To investigate the role of microtubule associated protein-tau (MAP-tau) and β-tubulin III (TUBB3) in predicting the chemosensitivity of paclitaxel in patients with advanced gastric cancer (GC).

METHODS

MAP-tau and TUBB3 expressions were detected using immunohistochemistry in 244 advanced GC patients prior to chemotherapy. The associations of MAP-tau and TUBB3 expressions with paclitaxel sensitivity were assessed using in vitro and in vivo xenograft analysis.

RESULTS

A total of 149 patients receiving paclitaxel plus capecitabine (cohort 1) and 95 patients receiving cisplatin plus capecitabine (cohort 2) were included in this study. In cohort 1, the clinical benefit rate (CBR), median progression-free survival (PFS) and overall survival (OS) were found to be significantly higher in patients with low levels of MAP-tau and TUBB3 expressions and were significantly higher than those in patients with high levels of MAP-tau and TUBB3 expressions (CBR: 72.2% versus 35.9%; PFS: 271 versus 102 days; OS: 394 versus 173 days; all P<0.05). This was not observed in cohort 2. In in vitro studies, the sensitivity of paclitaxel in human gastric cancer cells was inversely correlated with the expression levels of MAP-tau and TUBB3, as in in vivo animal xenografts.

CONCLUSIONS

The combination of MAP-tau and TUBB3 was found to predict chemosensitivity to paclitaxel in gastric cancer in vitro and in vivo. This merits further study and may help guide individual therapy.

Microtubules and their role in cellular stress in cancer

Microtubules are highly dynamic structures, which consist of α- and β-tubulin heterodimers, and are involved in cell movement, intracellular trafficking, and mitosis. In the context of cancer, the tubulin family of proteins is recognized as the target of the tubulin-binding chemotherapeutics, which suppress the dynamics of the mitotic spindle to cause mitotic arrest and cell death. Importantly, changes in microtubule stability and the expression of different tubulin isotypes as well as altered post-translational modifications have been reported for a range of cancers. These changes have been correlated with poor prognosis and chemotherapy resistance in solid and hematological cancers. However, the mechanisms underlying these observations have remained poorly understood. Emerging evidence suggests that tubulins and microtubule-associated proteins may play a role in a range of cellular stress responses, thus conferring survival advantage to cancer cells. This review will focus on the importance of the microtubule-protein network in regulating critical cellular processes in response to stress. Understanding the role of microtubules in this context may offer novel therapeutic approaches for the treatment of cancer.

The prognostic role of the class III β-tubulin in non-small cell lung cancer (NSCLC) patients receiving the taxane/vinorebine-based chemotherapy: a meta-analysis

Background

A number of studies have examined the relationship between the expression of the class III β-tubulin (TUBB3) and the treatment responses to the taxane/vinorebine-based chemotherapy in patients with non-small cell lung cancer (NSCLC). However, the results of these studies were inconsistent and inconclusive. Therefore, we conducted an up-to-date meta-analysis to evaluate the prognostic role of TUBB3 in the taxane/vinorebine-based chemotherapy.

Methods

A literature search for relevant studies was conducted in PubMed, Embase, and CNKI. The inclusion criteria were the taxane/vinorebine-based chemotherapy in patients with NSCLC and the evaluation of the clinical outcomes in relation to the expression of TUBB3. The clinical outcomes analyzed in this study included the overall response rate (ORR), overall survival (OS), and event-free survival (EFS). Odds ratio (OR) or hazard ratio (HR) with 95% confidence interval (CI) were calculated to assess the risk associated with the TUBB3 expression in the taxane/vinorebine-based chemotherapy.

Results

A total of 28 studies with 2401 NSCLC patients were qualified for this meta-analysis. We found that the positive or high level of TUBB3 expression was associated with a poorer ORR (OR = 0.24, 95% CI = 0.16–0.36, p<0.001), an unfavorable OS (HR = 1.52, 95% CI = 1.27–1.82, p<0.001), and a worse EFS (HR = 1.47, 95% CI = 1.24–1.74, p<0.001) compared to the negative or low level of TUBB3 expression. The statistically significant associations between TUBB3 and chemotherapy responses were also observed in the stratified subgroup analysis, which included the analysis by ethnic subgroup (Asian and Caucasian), chemotherapy regimen (taxane-based and vinorebine-based), TUBB3 detection method (IHC and PCR), and treatment strategy (surgery plus adjuvant chemotherapy and palliative chemotherapy).

Conclusions

The expression level of TUBB3 may be a useful biomarker to predict the clinical outcomes of the taxane/vinorebine-based chemotherapy in patients with NSCLC.

Expression of DNA translesion synthesis polymerase η in head and neck squamous cell cancer predicts resistance to gemcitabine and cisplatin-based chemotherapy

Purpose

The development of resistance against anticancer drugs has been a persistent clinical problem for the treatment of locally advanced malignancies in the head and neck mucosal derived squamous cell carcinoma (HNSCC). Recent evidence indicates that the DNA translesion synthesis (TLS) polymerase η (Pol η; hRad30a gene) reduces the effectiveness of gemcitabine/cisplatin. The goal of this study is to examine the relationship between the expression level of Pol η and the observed resistance against these chemotherapeutic agents in HNSCC, which is currently unknown.

Methods

Sixty-four mucosal derived squamous cell carcinomas of head and neck (HNSCC) from 1989 and 2007 at the City of Hope National Medical Center (Duarte, CA) were retrospectively analyzed. Pretreatment samples were immunostained with anti-Pol η antibody and the correlation between the expression level of Pol η and clinical outcomes were evaluated. Forty-nine cases treated with platinum (n=40) or gemcitabine (n=9) based chemotherapy were further examined for Pol η expression level for comparison with patient response to chemotherapy.

Results

The expression of Pol η was elevated in 67% of the head and neck tumor samples. Pol η expression level was significantly higher in grade 1 to grade 2 tumors (well to moderately differentiated). The overall benefit rate (complete response+ partial response) in patients treated with platinum and gemcitabine based chemotherapy was 79.5%, where low Pol η level was significantly associated with high complete response rate (p=0.03), although not associated with overall survival. Furthermore, no significant correlation was observed between Pol η expression level with gender, age, tobacco/alcohol history, tumor stage and metastatic status.

Conclusions

Our data suggest that Pol η expression may be a useful prediction marker for the effectiveness of platinum or gemcitabine based therapy for HNSCC.

Tubulin: an example of targeted chemotherapy

Anticancer drugs directed against the microtubule, including taxanes and vinca alkaloids, have been the backbone of many chemotherapy regimes for decades. These drugs have, however, significant limitations, which have prompted the development of novel microtubule targeting agents (MTAs). This article will discuss MTAs for anticancer therapies and recent debates regarding their mechanisms of action. Furthermore, the limitations of taxanes, including hypersensitivity reactions, neurotoxicity, drug resistance and lack of validated biomarkers to guide therapy will be discussed, all of which have driven the development of novel agents. The mechanisms of action and drug development of new generations of MTAs will also be outlined. Agents demonstrating utility in Phase III clinical trials, including eribulin, ixabepilone, cabazitaxel and trastuzumab-DM1 will be highlighted, as well as novel agents currently in development and future directions for MTAs.

Prognostic value of EGFR mutation and ERCC1 in patients with non-small cell lung cancer undergoing platinum-based chemotherapy

Background

In order to improve the outcome of patients with non-small cell lung cancer (NSCLC), a biomarker that can predict the efficacy of chemotherapy is needed. The aim of this study was to assess the role of EGFR mutations and ERCC1 in predicting the efficacy of platinum-based chemotherapy and the outcome of patients with NSCLC.

Methods

We conducted a retrospective study to analyze the relationships between EGFR mutations or ERCC1 expression and progression-free survival (PFS) in patients with NSCLC who received platinum-based chemotherapy. EGFR mutation status was determined using the peptide nucleic acid-locked nucleic acid polymerase chain reaction clamp method, and immunohistochemistry was used to examine the expression of ERCC1 in tumor samples obtained from the patients.

Results

Among the NSCLC patients who received platinum-based chemotherapy, the median PFS was significantly better in those who had never smoked and those with exon 19 deletion, and the median overall survival (OS) was significantly better in those who had never smoked, those with exon 19 deletion, and women. Cox regression analysis revealed that exon 19 deletion and having never smoked were significantly associated with both PFS and OS. Subset analysis revealed a significant correlation between ERCC1 expression and EGFR mutation, and ERCC1-negative patients with exon 19 deletion had a longer PFS than the other patients; ERCC1-positive patients without exon 19 deletion had a shorter PFS than the other patients.

Conclusions

Our results indicate that among NSCLC patients receiving platinum-based chemotherapy, those with exon 19 deletion have a longer PFS and OS. Our findings suggest that platinum-based chemotherapy is more effective against ERCC1-negative and exon 19-positive NSCLC.

ERCC1 and RRM1: ready for prime time?

The quest for markers of sensitivity to cytotoxic agents has been ongoing for decades. In non-small-cell lung cancer, platinum compounds represent the cornerstone of systemic therapy. They target DNA and induce damage that cancer cells struggle to overcome. Somatic excision repair cross-complementing rodent repair deficiency, complementation group 1 (ERCC1), and ribonucleotide reductase M1 (RRM1) expression levels have been extensively explored as markers of DNA repair capacity in tumor cells. Although low ERCC1 and/or RRM1 expression is generally associated with sensitivity to platinum, the results published in retrospective and prospective studies are not always consistent. Against this background, we will examine in this review the function of these two biomarkers as well as the tools available for their assessment and the associated technical issues. Their prognostic and predictive values will be summarized and considered in terms of customizing systemic therapy according to biomarker (ERCC1 and RRM1) expression levels. We will also discuss why the use of both markers should at this point be restricted to clinical research and underline that functional readouts of DNA repair will help boost future strategies for biomarker discovery in the field.

βIII-Tubulin: biomarker of taxane resistance or drug target?

INTRODUCTION

βIII-Tubulin (TUBB3) is predominantly expressed in neurons of the central and peripheral nervous systems, while in normal non-neoplastic tissues it is barely detectable. By contrast, this cytoskeletal protein is abundant in a wide range of tumors. βIII-Tubulin is linked to dynamic instability of microtubules (MTs), weakening the effects of agents interfering with MT polymerization. Based on this principle, early studies introduced the classical theory linking βIII-tubulin with a mechanism of counteracting taxane activity and accordingly, prompted its investigation as a predictive biomarker of taxane resistance.

AREAS COVERED

We reviewed 59 translational studies, including cohorts from lung, ovarian, breast, gastric, colorectal and various miscellaneous cancers subject to different chemotherapy regimens.

EXPERT OPINION

βIII-Tubulin functions more as a prognostic factor than as a predictor of response to chemotherapy. We believe this view can be explained by βIII-tubulin's association with prosurvival pathways in the early steps of the metastatic process. Its prognostic response increases if combined with additional biomarkers that regulate its expression, since βIII-tubulin can be expressed in conditions, such as estrogen exposure, unrelated to survival mechanisms and without any predictive activity. Additional avenues for therapeutic intervention could emerge if drugs are designed to directly target βIII-tubulin and its mechanism of regulation.

Individualized Chemotherapy in Advanced NSCLC Patients Based on mRNA Levels of BRCA1 and RRM1

OBJECTIVE

Experimental evidence suggests that the overexpression of breast cancer-specific tumor suppressor protein 1 (BRCA1) gene enhances sensitivity to docetaxel and resistance to cisplatin and ribonucleotide reductase M1 (RRM1) gene overexpression enhances resistance to gemcitabine. To further examine the effect of BRCA1 and RRM1 mRNA levels on outcome in advanced non-small cell lung cancer (NSCLC), we performed this non-randomized phase II clinical trial which tested the hypothesis that customized therapy would confer improved outcome over non-customized therapy.

METHODS

RNA was isolated from fresh tumor tissue. Patients received chemotherapy regimen based on their BRCA1 and RRM1 mRNA levels: both low-cisplatin plus gemcitabine (GP); both high-vinorelbine plus cisplatin (NP); BRCA1 low and RRM1 high-cisplatin plus docetaxel (TP); BRCA1 high and RRM1 low-vinorelbine plus gemcitabine (GN).

RESULTS

From Dec 2005 to Nov 2008, 94 metastatic and locally advanced NSCLC patients from our institute were enrolled in this study. The median age was 58 years old. Among them, 21 patients received GP, 30 patients received TP and 43 patients received NP chemotherapy. GP group had a higher response rate, and longer median time to progression (TTP) and median overall survival (OS) time than the other 2 groups. The response rates in the GP, TP and NP groups were 42.9%, 36.7% and 27.9%, respectively (P=0.568). The median TTP was 5.6, 5.0, 4.8 months (P=0.975), respectively, and the median OS time was 12.5, 11.0, 9.7 months (P=0.808), respectively.

CONCLUSION

Chemotherapy customized according to BRCA1 and RRM1 expression levels is associated with higher response rate and longer TTP and OS time in the GP group. This suggests that BRCA1 and RRM1 mRNA levels could be used as biomarkers in individual therapy in NSCLC.

A biomarker profile for predicting efficacy of cisplatin-vinorelbine therapy in malignant pleural mesothelioma

PURPOSE

Malignant pleural mesothelioma (MPM) has a dismal prognosis. Treatment results may be improved by biomarker-directed therapy. We investigated the baseline expression and impact on outcome of predictive biomarkers ERCC1, BRCA1, and class III β-tubulin in a cohort of MPM patients treated with cisplatin-vinorelbine. We further explored the possibility of combining markers into a treatment-response profile to increase the predictive power.

METHODS

Formalin-fixed paraffin-embedded tumor specimens from 54 MPM patients included in a phase II trial were evaluated for ERCC1, BRCA1, and class III β-tubulin by immunohistochemistry (IHC). Immunostaining was quantified by an H-score and dichotomized according to upper quartile values. The ERCC1- and class III β-tubulin-status classified patients as treatment resistant (ERCC1 positive + class III β-tubulin positive) or treatment responsive (ERCC1 negative + class III β-tubulin negative). The remaining marker combinations were considered inconclusive.

RESULTS

Fifty patients had tumor tissue available for IHC. Eleven had a responsive profile, and nine had a resistant profile. Thirty patients had an inconclusive profile. Median progression-free survival (PFS) was 6.7 months in the treatment-resistant group, 15.3 months in the treatment-responsive group, and 8.1 months in the inconclusive group (log-rank p = 0.03). Multivariate analysis revealed that treatment-resistant patients had a decreased PFS and overall survival (OS) compared with the treatment-responsive patients (HR 6.45, CI 95 % [2.02-20.64] p = 0.002 and HR 4.64, CI 95 % [1.56-13.79], p = 0.006, respectively). BRCA1 status was associated with neither PFS nor OS.

CONCLUSION

Combined negative ERCC1 and class III β-tubulin immunostaining is associated with significantly prolonged PFS and OS in MPM patients receiving cisplatin-vinorelbine therapy.

ERCC1 expression as a prognostic and predictive factor in patients with non-small cell lung cancer: a meta-analysis

It is hypothesized that high expression of the excision repair cross-complementation group 1 (ERCC1) gene might be a positive prognostic factor, but predict decreased sensitivity to platinum-based chemotherapy. Results from the published data are inconsistent. To derive a more precise estimation of the relationship between ERCC1 and the prognosis and predictive response to chemotherapy of non-small cell lung cancer (NSCLC), a meta-analysis was performed. An electronic search of the PubMed and Embase database was performed. Hazard ratio (HR) for overall survival (OS) was pooled in early stage patients received surgery alone to analyze the prognosis of ERCC1 on NSCLC. HRs for OS in patients received surgery plus adjuvant chemotherapy and in patients received palliative chemotherapy and relative risk (RR) for overall response to chemotherapy were aggregated to analyze the prediction of ERCC1 on NSCLC. The pooled HR indicated that high ERCC1 levels were associated with longer survival in early stage patients received surgery alone (HR, 0.69; 95% confidence interval (CI), 0.58-0.83; P = 0.000). There was no difference in survival between high and low ERCC1 levels in patients received surgery plus adjuvant chemotherapy (HR, 1.41; 95% CI, 0.93-2.12; P = 0.106). However, high ERCC1 levels were associated with shorter survival and lower response to chemotherapy in advanced NSCLC patients received palliative chemotherapy (HR, 1.75; 95% CI, 1.39-2.22; P = 0.000; RR, 0.77; 95% CI, 0.64-0.93; P = 0.007; respectively). The meta-analysis indicated that high ERCC1 expression might be a favourable prognostic and a drug resistance predictive factor for NSCLC.

βV-tubulin expression is associated with outcome following taxane-based chemotherapy in non-small cell lung cancer

Background:

Tubulin-binding agents (TBAs) are effective in non-small cell lung cancer (NSCLC) treatment. Both βIII- and βV-tubulins are expressed by cancer cells and may lead to resistance against TBAs.

Methods:

Pre-treatment samples from 65 locally advanced or oligometastatic NSCLC patients, who underwent uniform induction chemotherapy with paclitaxel and platinum followed by radiochemotherapy with vinorelbine and platinum were retrospectively analysed by immunohistochemistry. Protein expression of βIII- and βV-tubulin was morphometrically quantified.

Results:

Median pre-treatment H-score for βIII-tubulin was 110 (range: 0–290), and 160 for βV-tubulin (range: 0–290). Low βIII-tubulin expression was associated with improved overall survival (OS) (P=0.0127, hazard ratio (HR): 0.328). An association between high βV-tubulin expression and prolonged progression-free survival (PFS, median 19.2 vs 9.4 months in high vs low expressors; P=0.0315, HR: 1.899) was found. Further, high βV-tubulin expression was associated with objective response (median H-score 172.5 for CR+PR vs 120 for SD+PD patients, P=0.0104) or disease control following induction chemotherapy (170 for CR+PR+SD vs 100 for PD patients, P=0.0081), but not radiochemotherapy.

Conclusion:

Expression of βV-tubulin was associated with treatment response and PFS following paclitaxel-based chemotherapy of locally advanced and oligometastatic NSCLC patients. Prolonged OS was associated with low levels of βIII-tubulin. Prospective evaluation of βIII/βV-tubulin expression in NSCLC is warranted.

Serum levels of TUBB3 correlate with clinical outcome in Chinese patients with advanced gastric cancer receiving first-line paclitaxel plus capecitabine

The overexpression of β-tubulin III (TUBB3) in tumor tissues was reversely related with the efficacy of paclitaxel and clinical outcome in different cancers. In this study, we aimed to investigate the association between serum levels of TUBB3 and clinical outcome in advanced gastric cancer patients receiving first-line paclitaxel plus capecitabine. One hundred and twenty-eight advanced gastric cancer patients receiving first-line paclitaxel plus capecitabine in Peking University Cancer Hospital from December 2006 to October 2010 were enrolled in the study. Serum samples from 32 healthy individuals were used as controls. TUBB3 expression level in advanced gastric cancer was significantly higher than that in healthy control group (31.6 ± 17.8 ng/mL vs. 16.9 ± 3.8 ng/mL, p < 0.001). For all patients, the clinical benefit rate (CBR), median progression-free survival (PFS), and overall survival (OS) were 55.6 %, 179 and 306 days, respectively. The CBR, median PFS, and OS in patients with low (n = 27) and high levels (n = 101) of TUBB3 were 95.8 %/45.1 % (low vs. high, p < 0.001), 190 days/166 days (p = 0.064), and 360 days/297 days (p = 0.023), respectively. Cox multivariate regression analysis demonstrated that the serum levels of TUBB3 were an independent prognostic factor for advanced gastric cancer patients (HR = 1.950; 95 % CI, 1.242-3.062; p = 0.004). This study indicated that low levels of TUBB3 in serum could predict better response and survival for advanced gastric cancer patients receiving paclitaxel plus capecitabine, which could be used to select patients who would benefit from this regimen.

Role of excision repair cross-complementation 1 expression as a prognostic marker for response to radiotherapy in early-stage laryngeal cancer

BACKGROUND

High expression of excision repair cross-complementation 1 (ERCC1) predicts for resistance to platinum-based chemotherapy or chemoradiotherapy. We evaluated the prognostic value of ERCC1 expression in a cohort of laryngeal cancer treated with radiotherapy alone.

METHODS

ERCC1 expression was examined by immunohistochemical analysis of tissue microarrays constructed from 123 patients with stages I-II laryngeal squamous cell carcinoma treated with standard radiotherapy.

RESULTS

ERCC1 expression did not correlate with clinicopathologic risk factors, local control, or overall survival. At 5 years, local control was 75% versus 71% (p = .78) and overall survival was 68% versus 54% (p = .65), for nonexpressors and expressors of ERCC1, respectively. On multivariate analysis, T classification predicted for local control, and T classification and age predicted for overall survival.

CONCLUSIONS

ERCC1 expression did not predict for radiotherapy resistance or worse survival. Therefore, radiotherapy remains an effective treatment in tumors with high ERCC1 expression.

Combined analysis of mRNA expression of ERCC1, BAG-1, BRCA1, RRM1 and TUBB3 to predict prognosis in patients with non-small cell lung cancer who received adjuvant chemotherapy

BACKGROUND

The aim of this study was to investigate prognostic value of excision repair cross-complementing 1 (ERCC1), BCL2-associated athanogene (BAG-1), the breast and ovarian cancer susceptibility gene 1 (BRCA1), ribonucleotide reductase subunit M1 (RRM1) and class III β-tubulin (TUBB3) in patients with non-small cell lung cancer (NSCLC) who received platinum- based adjuvant chemotherapy.

METHODS

Messenger RNA expressions of these genes were examined in 85 tumor tissues and 34 adjacent tissue samples using semi-quantitative RT-PCR. The expressions of these five genes were analyzed in relation to chemotherapy and progression-free survival (PFS) and overall survival (OS). Seventy-four patients were enrolled into chemotherapy.

RESULTS

Patients with ERCC1 or BAG-1 negative expression had a significantly longer PFS (P = 0.001 and P = 0.001) and OS (P = 0.001 and P = 0.001) than those with positive expression. Patients with negative ERCC1 and BAG-1 expression benefited more from platinum regimen (P = 0.001 and P = 0.002). Patients with BRCA1 negative expression might have a longer OS (P = 0.052), but not PFS (P = 0.088) than those with BRCA1 positive expression. A significant relationship was observed between the mRNA expression of ERCC1 and BAG-1 (P = 0.042). In multivariate analysis, ERCC1 and BAG-1 were significantly favorable factors for PFS (P = 0.018 and P = 0.017) and OS (P = 0.027 and P = 0.022).

CONCLUSIONS

ERCC1 and BAG-1 are determinants of survival after surgical treatment of NSCLC, and its mRNA expression in tumor tissues could be used to predict the prognosis of NSCLC treated by platinum.

The role of βIII-tubulin in non-small cell lung cancer patients treated by taxane-based chemotherapy

BACKGROUND

The aim of this study is to evaluate whether class III β-tubulin (TUBB3) expression could predict progression-free survival or overall survival in relapsed non-small cell lung cancer (NSCLC) patients treated with taxene-based chemotherapy.

METHODS

Immunohistochemistal staining was used to examine the expression of TUBB3 in resected lung tumor specimens obtained from 56 patients treated with platinum-based chemotherapy against recurrent tumors after curative resections. Excision repair cross-complementation group 1, breast cancer susceptibility gene 1, vascular endothelial growth factor, Ki-67, CD34, and p53 were also correlated with clinical features and outcome after treatment.

RESULTS

Of the 56 patients enrolled in the study, 29 were treated by carboplatin plus paclitaxel as first-line treatment, and 24 patients received docetaxel monotherapy as second- or third-line treatment. A positive TUBB3 expression is closely associated with a poor response to taxane-based chemotherapy. TUBB3 expression was an independent prognostic factor for predicting poor progression-free survival after docetaxel administration. However, TUBB3 expression could not predict outcome after carboplatin plus paclitaxel treatment. The other biomarkers tested were not independent prognostic factors for predicting outcome after taxane-based chemotherapy.

CONCLUSION

TUBB3 expression is associated with resistance to taxane-based chemotherapy and is an independent prognostic factor for predicting poor progression-free survival after docetaxel treatment alone. TUBB3 expression may be a predictive marker for chemoresistance to docetaxel in NSCLC with postoperative recurrent disease.

Cross-validation study of class III beta-tubulin as a predictive marker for benefit from adjuvant chemotherapy in resected non-small-cell lung cancer: analysis of four randomized trials

BACKGROUND

The IALT, JBR.10, ANITA and Cancer and Leukemia Group B 9633 trials compared adjuvant chemotherapy with observation for patients with resected non-small-cell lung cancer (R-NSCLC). Data from the metastatic setting suggest high tumor class III beta-tubulin (TUBB3) expression is a determinant of insensitivity to tubulin-targeting agents (e.g. vinorelbine, paclitaxel). In 265 patients from JBR.10 (vinorelbine-cisplatin versus observation), high TUBB3 was an adverse prognostic factor and was associated (nonsignificantly) with 'greater' survival benefit from chemotherapy. We explored this further in additional patients from JBR.10 and the other three trials.

PATIENTS AND METHODS

TUBB3 immunohistochemical staining was scored for 1149 patients on the four trials. The original JBR.10 cut-off scores were used to classify tumors as TUBB3 high or low. The prognostic and predictive value of TUBB3 on disease-free survival (DFS) and overall survival (OS) was assessed by Cox models stratified by trial and adjusted for clinical factors.

RESULTS

High TUBB3 expression was prognostic for OS [hazard ratio (HR)=1.27 (1.07-1.51), P=0.008) and DFS [HR=1.30 (1.11-1.53), P=0.001). TUBB3 was not predictive of a differential treatment effect [interaction P=0.20 (OS), P=0.23 (DFS)]. Subset analysis (n=420) on vinorelbine-cisplatin gave similar results.

CONCLUSIONS

The prognostic effect of high TUBB3 expression in patients with R-NSCLC has been validated. We were unable to confirm a predictive effect for TUBB3.

Excision repair cross-complementation group 1 (ERCC1) status and lung cancer outcomes: a meta-analysis of published studies and recommendations

Purpose

Despite discrepant results on clinical utility, several trials are already prospectively randomizing non-small cell lung cancer (NSCLC) patients by ERCC1 status. We aimed to characterize the prognostic and predictive effect of ERCC1 by systematic review and meta-analysis.

Methods

Eligible studies assessed survival and/or chemotherapy response in NSCLC or SCLC by ERCC1 status. Effect measures of interest were hazard ratio (HR) for survival or relative risk (RR) for chemotherapy response. Random-effects meta-analyses were used to account for between-study heterogeneity, with unadjusted/adjusted effect estimates considered separately.

Results

23 eligible studies provided survival results in 2,726 patients. Substantial heterogeneity was observed in all meta-analyses (I² always >30%), partly due to variability in thresholds defining ‘low’ and ‘high’ ERCC1. Meta-analysis of unadjusted estimates showed high ERCC1 was associated with significantly worse overall survival in platinum-treated NSCLC (average unadjusted HR = 1.61, 95%CI:1.23–2.1, p = 0.014), but not in NSCLC untreated with chemotherapy (average unadjusted HR = 0.82, 95%CI:0.51–1.31). Meta-analysis of adjusted estimates was limited by variable choice of adjustment factors and potential publication bias (Egger's p<0.0001). There was evidence that high ERCC1 was associated with reduced response to platinum (average RR = 0.80; 95%CI:0.64–0.99). SCLC data were inadequate to draw firm conclusions.

Conclusions

Current evidence suggests high ERCC1 may adversely influence survival and response in platinum-treated NSCLC patients, but not in non-platinum treated, although definitive evidence of a predictive influence is lacking. International consensus is urgently required to provide consistent, validated ERCC1 assessment methodology. ERCC1 assessment for treatment selection should currently be restricted to, and evaluated within, clinical trials.

Expression of excision repair cross-complementation group 1 as predictive marker for nasopharyngeal cancer treated with concurrent chemoradiotherapy

PURPOSE

Cisplatin-based concurrent chemoradiotherapy is the standard treatment of nasopharyngeal cancer. The expression of excision repair cross-complementation group 1 (ERCC1) has been reported to be associated with resistance to platinum-based chemotherapy. We evaluated whether ERCC1 expression could predict the treatment response and survival outcome of patients with locally advanced nasopharyngeal cancer who were treated with cisplatin-based concurrent chemoradiotherapy.

METHODS AND MATERIALS

Immunohistochemistry was used to examine the expression of ERCC1 in nasopharyngeal tumor tissue. Patients were categorized into either a resistant or sensitive group depending on their treatment response outcome. A total of 77 patients were assessed in the present study.

RESULTS

The resistant and sensitive groups included 25 and 52 patients, respectively. ERCC1 expression was positive in the tumor tissue for 39 of the 77 patients (51%). Significantly more ERCC1-negative tumors were in the sensitive group than in the resistant group (p = .035). In terms of survival outcome, univariate analysis determined that patients with ERCC1-negative tumors had longer disease-free survival (p = .076) and overall survival (p = .013) than patients with ERCC1-positive tumors. Multivariate analysis determined that negative ERCC expression in tumors was an independent predictor for prolonged overall survival (hazard ratio, 0.14; 95% confidence interval, 0.03-0.71).

CONCLUSION

These results suggest that ERCC1 expression might be a useful predictive marker in patients with locally advanced nasopharyngeal cancer who are under consideration for cisplatin-based concurrent chemoradiotherapy.