Class III beta-tubulin expression and benefit from adjuvant cisplatin/vinorelbine chemotherapy in operable non-small cell lung cancer: analysis of NCIC JBR.10

Low tumor interleukin-1β expression predicts a limited effect of adjuvant platinum-based chemotherapy for patients with completely resected lung adenocarcinoma: An identification and validation study

INTRODUCTION AND OBJECTIVES

Adjuvant platinum-based chemotherapy for completely resected non-small cell lung cancer is associated with modest improvement in survival; nevertheless, no validated biomarker exists for predicting the benefit or harm of adjuvant platinum-based chemotherapy.

MATERIALS AND METHODS

We simultaneously measured 27 cytokines in operative tumor specimens from a discovery cohort (n = 97) by multiplex immunoassay; half of the patients received adjuvant platinum-based chemotherapy, and the other half were observed. We tested possible prognostic and predictive factors in multivariate Cox models for overall survival (OS) and relapse-free survival (RFS), and a tree-based method was applied to detect predictive factors with respect to RFS. The results were validated in an independent validation cohort (n = 93).

RESULTS

Fifty-two of 97 (54 %) patients in the discovery cohort and 50 of 93 (54 %) in the validation cohort received adjuvant chemotherapy; forty-four (85 %) patients in the discovery cohort and 37 (74 %) in the validation cohort received four cycles as planned. In patients with low IL-1β-expressing tumors, RFS and OS were worse after adjuvant chemotherapy than after observation. The limited effect of adjuvant chemotherapy for patients with low IL-1β-expressing tumors was confirmed in the validation cohort. Additionally, RFS and OS were prolonged by adjuvant chemotherapy only in patients with high IL-1β-expressing tumors in the validation cohort.

CONCLUSIONS

This study identified and validated low tumor IL-1β expression as a potential biomarker of a limited response to adjuvant platinum-based chemotherapy after complete resection of pulmonary adenocarcinoma. This finding has the potential to inform adjuvant treatment decisions.

Class III β-Tubulin Expression Is of Value in Selecting nab -Paclitaxel and Gemcitabine as First-Line Therapy in Unresectable Pancreatic Cancer

OBJECTIVES

Nab -paclitaxel and gemcitabine (GnP) or FOLFIRINOX (a combination of leucovorin, fluorouracil, irinotecan, and oxaliplatin [FFX]) is currently recognized as the standard first-line regimen for unresectable pancreatic ductal adenocarcinoma (PDAC). Class III β-tubulin (TUBB3) has the potential to predict resistance to taxane in various tumors; therefore, this study aimed to clarify whether TUBB3 is a predictive marker for GnP response.

METHODS

We retrospectively reviewed 113 patients with PDAC who received GnP or FFX as first-line chemotherapy and examined immunohistochemically the TUBB3 expression in specimens obtained by endoscopic ultrasound-guided fine-needle aspiration.

RESULTS

High TUBB3 expression was associated with a significantly lower disease control rate ( P = 0.017) and shorter progression-free survival (PFS) ( P = 0.019), and multivariate analysis revealed that TUBB3 expression was an independent variable for PFS in the GnP first-line group ( P = 0.045). In addition, in the FFX first-line group, TUBB3 expression was not correlated with PFS or overall survival (OS). In all 113 patients, TUBB3 expression was not also associated with OS.

CONCLUSIONS

Class III β-tubulin might be a predictive factor for the response of GnP, but not a prognostic factor for OS, helping the selection of an optimized first-line chemotherapy regimen for unresectable PDAC.

Diagnostic, Predictive, and Prognostic Biomarkers in Non-Small Cell Lung Cancer (NSCLC) Management

Lung cancer is the leading cause of cancer-related deaths worldwide. Despite growing efforts for its early detection by screening populations at risk, the majority of lung cancer patients are still diagnosed in an advanced stage. The management of lung cancer has dramatically improved in the last decade and is no longer based on the "one-fits-all" paradigm or the general histological classification of non-small cell versus small cell lung cancer. Emerging options of targeted therapies and immunotherapies have shifted the management of lung cancer to a more personalized treatment approach, significantly influencing the clinical course and outcome of the disease. Molecular biomarkers have emerged as valuable tools in the prognosis and prediction of therapy response. In this review, we discuss the relevant biomarkers used in the clinical management of lung tumors, from diagnosis to prognosis. We also discuss promising new biomarkers, focusing on non-small cell lung cancer as the most abundant type of lung cancer.

Immunohistochemical validation study of 15-gene biomarker panel predictive of benefit from adjuvant chemotherapy in resected non-small-cell lung cancer: analysis of JBR.10

Objective

There are no validated approaches to predict benefit from adjuvant chemotherapy for resected patients with non-small-cell lung cancer (NSCLC). The aim of this study was to translate a 15-gene mRNA expression profile published by Zhu et al, shown to be prognostic and predictive of benefit, into a readily applicable immunohistochemistry (IHC) panel.

Methods

For seven of the genes in the gene expression profile (GEP) for which suitable commercial antibodies were available, we semiquantitatively assessed the IHC expression and prognostic significance for 173 patients treated at the Saint John Regional Hospital (SJRH). Cut-offs for high and low expression were defined for each marker and applied to IHC scores from 291 of the 482 patients in JBR.10, including patients on both the adjuvant chemotherapy and observation arms. The prognostic and predictive value of these markers on overall survival (OS) or recurrence-free survival (RFS) was assessed by Cox regression models.

Results

In the SJRH cohort, in 62 patients with resected stage II–III NSCLC, the prognostic significance of IHC assays for four proteins were concordant with Zhu’s GEP results. Low FOSL2 (OS, HR=0.15; p=0.0001; RFS, HR=0.14; p<0.0001) and high STMN2 (RFS, HR=2.501; p=0.0197) were adverse prognostic factors. Low ATP1B1 and low TRIM14 expression trended toward worse OS and RFS. Validation of these markers with JBR.10 patients failed to show prognostic significance either individually or in combined risk classifications. Additionally, the interaction between these markers and chemotherapy treatment in predicting OS (FOSL2, p=0.52; STMN2 p=0.14; ATP1B1, p=0.33; TRIM14, p=0.81) or RFS (FOSL2, p=0.63; STMN2, p=0.12; ATP1B1, p=0.66; TRIM14, p=0.57) did not reach significance, individually or in combination panels.

Conclusions

Zhu’s GEP could not be translated into an IHC panel predictive of benefit from adjuvant chemotherapy. Future predictive biomarker analysis in the adjuvant NSCLC setting may need to focus on novel therapies.

BET inhibition increases βIII-tubulin expression and sensitizes metastatic breast cancer in the brain to vinorelbine

Metastases from primary breast cancer result in poor survival. βIII-tubulin (TUBB3) has been established as a therapeutic target for breast cancer metastases specifically to the brain. In this study, we conducted a systematic analysis to determine the regulation of TUBB3 expression in breast cancer metastases to the brain and strategically target these metastases using vinorelbine (VRB), a drug approved by the U.S. Food and Drug Administration (FDA). We found that human epidermal growth factor receptor 2 (HER2) signaling regulates TUBB3 expression in both trastuzumab-sensitive and trastuzumab-resistant neoplastic cells. We further discovered that bromodomain and extra-terminal domain (BET) inhibition increases TUBB3 expression, rendering neoplastic cells more susceptible to apoptosis by VRB. Orthotopic xenograft assays using two different breast cancer cell models revealed a reduction in tumor volume with BET inhibition and VRB treatment. In addition, in vivo studies using a model of multiple brain metastasis (BM) showed improved survival with the combination of radiation + BET inhibitor (iBET-762) + VRB (75% long-term survivors, P < 0.05). Using in silico analysis and BET inhibition, we found that the transcription factor myeloid zinc finger-1 (MZF-1) protein binds to the TUBB3 promoter. BET inhibition decreases MZF-1 expression and subsequently increases TUBB3 expression. Overexpression of MZF-1 decreases TUBB3 expression and reduces BM in vivo, whereas its knockdown increases TUBB3 expression in breast cancer cells. In summary, this study demonstrates a regulatory mechanism of TUBB3 and provides support for an application of BET inhibition to sensitize breast cancer metastases to VRB-mediated therapy.

Predictive markers based on transcriptome modules for vinorelbine-based adjuvant chemotherapy for lung adenocarcinoma patients

OBJECTIVES

Microtubule inhibitors (MTIs) are widely used as anti-cancer drugs for various types of tumors. Vinorelbine, an MTI, is utilized in postoperative adjuvant chemotherapy, especially for lung adenocarcinoma. However, no molecular markers are able to identify patients for whom MTIs would be effective. In this study, we attempted to identify practical markers to predict the efficacy of MTI-based adjuvant chemotherapy.

MATERIALS AND METHODS

We explored a novel combination of molecular marker candidates, based on gene expression network analysis constructed using an omics panel of 26 lung adenocarcinoma cell lines. We then applied the obtained classification method to predict the efficacy of MTI treatment in patients who received adjuvant chemotherapy. RNA sequencing (RNA-seq) analysis was conducted using surgical specimens from 24 Japanese lung adenocarcinoma patients treated postoperatively with vinorelbine.

RESULTS

We identified four modules within the network with module activities that were significantly associated with sensitivity to MTIs. Two modules were associated with high sensitivity to MTIs: genes with low differentiation or transdifferentiation of lung adenocarcinomas. On the other hand, MTI-low sensitivity modules were enriched in common epithelial genes and markers of well-differentiated lung adenocarcinomas. We also classified lung adenocarcinoma cases using the module activities associated with MTI efficacy and stratify the cases with MTI resistance.

CONCLUSION

We demonstrate that the constructed classification method is useful for identifying patients with MTI resistance which results in a high risk of cancer relapse.

High LARGE1 Expression May Predict Benefit from Adjuvant Chemotherapy in Resected Non-Small-Cell Lung Cancer

Background

LARGE1 plays a pivotal role in glycosylation of alpha-Dystroglycan (α-DG) and is aberrantly downregulated in cell lines originating from epithelium-derived cancers including lung cancer. However, the expression of LARGE1 and its clinical significance in NSCLC are not clear.

Materials and Methods

The data were collected from the TCGA database to investigate LARGE1 expression in stage I–III NSCLC and explore its associations with clinicopathological parameters and overall survival of patients. The prognostic role of LARGE1 was examined in subgroups according to clinical features and treatments. The results were validated in external cohorts from the NCBI GEO database. Gene Set Enrichment Analysis (GSEA) was performed to investigate the potential molecular mechanisms during LARGE1 alteration in NSCLC.

Results

LARGE1 was aberrantly downregulated in NSCLC compared with adjacent tissues and normal lung tissues and in tumors with advanced stage compared with early stage. There was only a trend of association between high LARGE1 with OS in multivariate analysis. Surprisingly, high LARGE1 was significantly associated with improved OS in a subgroup of the patients with adjuvant chemotherapy (ACT) and a significant interaction between LARGE1 expression and ACT was found. Improved OS after ACT was also found in patients with high LARGE1 compared to those with low LARGE1. When combining LARGE1 expression and ACT, compared with patients with non-ACT, HR of low LARGE1/ACT was 0.592 (95% CI=0.432–0.813, P=0.0012), and HR of high LARGE1/ACT was 0.124 (95% CI=0.031–0.505, P=0.0036). The results were verified in two external cohorts from the GEO database. GSEA indicated that LARGE1 might downregulate cell cycle pathway to improve ACT sensitivity and subsequently the prognosis in NSCLC.

Conclusion

High LARGE1 can be used to identify the patients with resected stage I–III NSCLC most likely to benefit from adjuvant chemotherapy.

An Overview of Promising Biomarkers in Cancer Screening and Detection

Applications of biomarkers have been proved in oncology screening, diagnosis, predicting response to treatment as well as monitoring the progress of the disease. Considering the crucial role played by them during different disease stages, it is extremely important to evaluate, validate, and assess them to incorporate them into routine clinical care. In this review, the role of few most promising and successfully used biomarkers in cancer detection, i.e. PD-L1, E-Cadherin, TP53, Exosomes, cfDNA, EGFR, mTOR with regard to their structure, mode of action, and reports signifying their pathological significance, are addressed. Also, an overview of some successfully used biomarkers for cancer medicine has been presented. The study also summarizes biomarker-driven personalized cancer therapy i.e., approved targets and indications, as per the US FDA. The review also highlights the increasingly prominent role of biomarkers in drug development at all stages, with particular reference to clinical trials. The increasing utility of biomarkers in clinical trials is clearly evident from the trend shown, wherein ~55 percent of all oncology clinical trials in 2019 were seen to involve biomarkers, as opposed to ~ 15 percent in 2001, which clearly proves the essence and applicability of biomarkers for synergizing clinical information with tumor progression. Still, there are significant challenges in the implementation of these possibilities with strong evidence in cost-- effective manner.

Intrinsic and Extrinsic Factors Affecting Microtubule Dynamics in Normal and Cancer Cells

Microtubules (MTs), highly dynamic structures composed of α- and β-tubulin heterodimers, are involved in cell movement and intracellular traffic and are essential for cell division. Within the cell, MTs are not uniform as they can be composed of different tubulin isotypes that are post-translationally modified and interact with different microtubule-associated proteins (MAPs). These diverse intrinsic factors influence the dynamics of MTs. Extrinsic factors such as microtubule-targeting agents (MTAs) can also affect MT dynamics. MTAs can be divided into two main categories: microtubule-stabilizing agents (MSAs) and microtubule-destabilizing agents (MDAs). Thus, the MT skeleton is an important target for anticancer therapy. This review discusses factors that determine the microtubule dynamics in normal and cancer cells and describes microtubule-MTA interactions, highlighting the importance of tubulin isoform diversity and post-translational modifications in MTA responses and the consequences of such a phenomenon, including drug resistance development.

Association of high TUBB3 with resistance to adjuvant docetaxel-based chemotherapy in gastric cancer: translational study of ITACA-S

BACKGROUND

No predictive markers for chemotherapy activity have been validated in gastric cancer (GC). The potential value of class III β-tubulin (TUBB3) as biomarker for prognosis and resistance to taxane-based therapy was reported.

METHODS

We analyzed GC samples of patients enrolled in the Intergroup Trial of Adjuvant Chemotherapy in Adenocarcinoma of the Stomach (ITACA-S), a randomized adjuvant study comparing 5-fluorouracil/leucovorin (5-FU/LV) and docetaxel-based sequential chemotherapy. TUBB3 was quantitated by selected reaction monitoring mass spectrometry and patients were stratified using a threshold of 750 attomoles per microgram (amol/µg). Cox proportional modeling and Kaplan-Meier survival analysis were used to assess the impact of TUBB3 expression on overall survival (OS) and disease-free survival.

RESULTS

Patients with TUBB3 protein levels >750 and <750 amol/µg were 21.9% and 78.1%, respectively, and were well-balanced between treatment arms. TUBB3 protein levels were not prognostic. Whereas no survival differences according to the 2 arms were observed in the subgroup with low TUBB3 expression (5-year OS 47% vs 40%; p = 0.44), patients with high TUBB3 had a clinically meaningful poorer OS when receiving docetaxel-based versus 5-FU/LV chemotherapy (5-year OS 31% vs 54%; p = 0.09), with a statistically significant interaction between TUBB3 and treatment (p = 0.049).

CONCLUSIONS

The quantification of TUBB3 might be considered as a negative predictive biomarker of benefit from taxane-based therapy in GC. Studies are needed to evaluate its role in the neoadjuvant setting.

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.

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.

The Microtubule Network and Cell Death Are Regulated by an miR-34a/Stathmin 1/βIII-Tubulin Axis

MicroRNA-34a (miR-34a) is a master regulator of signaling networks that maintains normal physiology and disease and is currently in development as a miRNA-based therapy for cancer. Prior studies have reported low miR-34a expression in osteosarcoma; however, the molecular mechanisms underlying miR-34a activity in osteosarcoma are not well-defined. Therefore, this study evaluated the role of miR-34a in regulating signal transduction pathways that influence cell death in osteosarcoma. Levels of miR-34a were attenuated in human osteosarcoma cells and xenografts of the Pediatric Preclinical Testing Consortium (PPTC). Bioinformatics predictions identified stathmin 1 (STMN1) as a potential miR-34a target. Biotin pull-down assay and luciferase reporter analysis confirmed miR-34a target interactions within the STMN1 mRNA 3'-untranslated region. Overexpression of miR-34a in osteosarcoma cells suppressed STMN1 expression and reduced cell growth in vitro Restoration of miR-34a led to microtubule destabilization and increased βIII-tubulin expression, with corresponding G1-G2 phase cell-cycle arrest and apoptosis. Knockdown of the Sp1 transcription factor, by siRNA silencing, also upregulated βIII-tubulin expression in osteosarcoma cells, suggesting that miR-34a indirectly affects Sp1. Validating the coordinating role of miR-34a in microtubule destabilization, when miR-34a was combined with either microtubule inhibitors or chemotherapy, STMN1 phosphorylation was suppressed and there was greater cytotoxicity in osteosarcoma cells. These results demonstrate that miR-34a directly represses STMN1 gene and protein expression and upregulates βIII-tubulin, leading to disruption of the microtubule network and cell death.Implications: The miR-34a/STMN1/βIII-tubulin axis maintains the microtubule cytoskeleton in osteosarcoma, and combining miR-34a with microtubule inhibitors can be investigated as a novel therapeutic strategy. Mol Cancer Res; 15(7); 953-64. ©2017 AACR.

Clinicopathological and immunohistochemical features of lung invasive mucinous adenocarcinoma based on computed tomography findings

Background

We performed an analysis to clarify differences in clinicopathological and molecular features of lung invasive mucinous adenocarcinoma (IMA) based on computed tomography (CT) findings and their impact on prognosis.

Patients and methods

On the basis of CT findings, we divided lung IMA into three subtypes: solid, bubbling, and pneumonic. We then investigated differences in clinicopathological characteristics, prognosis, and the expressions of well-identified biomarkers, including cyclooxygenase-2 (Cox-2), excision repair cross-complementation group 1 (ERCC1), ribonucleotide reductase M1 (RRM1), class III beta-tubulin, thymidylate synthase (TS), secreted protein acidic and rich in cysteine (SPARC), programmed cell death-1 ligand-1 (PD-L1), and epidermal growth factor receptor mutation, among the three subtypes.

Results

A total of 29 patients with resected lung IMA were analyzed. Compared with the solid or bubbling type, the pneumonic type had a higher proportion of symptoms, a larger tumor size, a higher pathological stage, and a significantly worse prognosis. The immunohistochemical findings tended to show high expression of RRM1, class III beta-tubulin, and Cox-2 in the tumor and of SPARC in the stroma, but not of ERCC1, TS, and PD-L1 in the tumor. None of the biomarkers with high expression levels in the tumor were prognostic biomarkers, but the expression of SPARC in the stroma was correlated with a poor outcome.

Conclusion

Clinical and pathological features, in conjunction with molecular data, indicate that IMA should be divided into different subgroups. In our results, the pneumonic type was correlated with a significantly worse outcome. Further studies should be performed to confirm our conclusion and to explore its molecular implications.

Predictors of chemotherapy efficacy in non-small-cell lung cancer: a challenging landscape

BACKGROUND

Conventional cytotoxic chemotherapy (CCC) is the backbone of non-small-cell lung cancer (NSCLC) treatment since decades and still represents a key element of the therapeutic armamentarium. Contrary to molecularly targeted therapies and immune therapies, for which predictive biomarkers of activity have been actively looked for and developed in parallel to the drug development process ('companion biomarkers'), no patient selection biomarker is currently available for CCC, precluding customizing treatment.

MATERIALS AND METHODS

We reviewed preclinical and clinical studies that assessed potential predictive biomarkers of CCC used in NSCLC (platinum, antimetabolites, topoisomerase inhibitors, and spindle poisons). Biomarker evaluation method, analytical validity, and robustness are described and challenged for each biomarker.

RESULTS

The best-validated predictive biomarkers for efficacy are currently ERCC1, RRM1, and TS for platinum agents, gemcitabine and pemetrexed, respectively. Other potential biomarkers include hENT1 for gemcitabine, class III β-tubulin for spindle poisons, TOP2A expression and CEP17 duplication (mostly studied for predicting anthracyclines efficacy) whose applicability concerning etoposide would deserve further evaluation. However, none of these biomarkers has till now been validated prospectively in an appropriately designed and powered randomised trial, and none of them is currently ready for implementation in routine clinical practice.

CONCLUSION

The search for predictive biomarkers to CCC has been proven challenging. If a plethora of biomarkers have been evaluated either in the preclinical or in the clinical setting, none of them is ready for clinical implementation yet. Considering that most mechanisms of resistance or sensitivity to CCC are multifactorial, a combinatorial approach might be relevant and further efforts are required.

Biomarkers for efficacy of adjuvant chemotherapy following complete resection in NSCLC stages I-IIIA

Biomarkers may be useful when deciding which nonsmall cell lung cancer (NSCLC) patients may benefit from adjuvant chemotherapy following complete resection and which chemotherapeutic agents may be used preferably in individual patients in order to maximise survival.

A literature search covering the period from 2003 to May, 2014 was conducted using PubMed and the following search terms: “non-small cell lung cancer”, “NSCLC”, “adjuvant chemotherapy”, “randomized”, “randomised”, “biomarkers”, “prognostic”, “predictive”. This review focuses on current knowledge of biomarkers for prognosis or efficacy of adjuvant treatment following complete resection in stage I–IIIA NSCLC patients.

This review includes results on 18 different biomarkers and five gene profiles. A statistically significant prognostic impact was reported for: iNTR, TUBB3, RRM1, ERCC1, BRCA1, p53, MRP2, MSH2, TS, mucin, BAG-1, pERK1/2, pAkt-1, microRNA, TopIIA, 15-gene profile, 92-gene profile, 31-gene profile and 14-gene profile. A statistically significant predictive impact was reported for: ERCC1, p53, MSH2, p27, TUBB3, PARP1, ATM, 37-gene profile, 31-gene profile, 15-gene profile and 92-gene profile.

Uncertainties regarding the optimal analysis method and cut-off levels for the individual markers may blur the prognostic or predictive signals. None of the possible predictive markers have been validated in prospective trials. Thus, there are no biomarkers ready to use in an adjuvant setting in NSCLC.

Further investigation and validation is required to explore biomarkers in completely resected NSCLC stage I–IIIAhttp://ow.ly/M0leE

Chemotherapy Resistance in Lung Cancer

Despite a growing interest in development of non-cytotoxic targeted agents, systemic chemotherapy is still the mainstay of treatment for both non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). However, chemotherapy resistance limits our ability to effectively treat advanced lung cancer. Some lung tumors are intrinsically resistant to chemotherapy, and in virtually all cases, even the initial responders rapidly develop acquired resistance. While targeting histology could result in enhanced tumor sensitivity to a particular chemotherapeutic agent, better understanding of molecular determinants of chemotherapy sensitivity/resistance would be critically important. Development of predictive biomarkers to personalize chemotherapeutic agents and combining novel agents targeting specific resistance pathways with standard chemotherapy could be some promising strategies to overcome chemotherapy resistance in lung cancer. In this chapter, we will discuss some key mechanisms of resistance for commonly used chemotherapeutic agents in lung cancer.

[Current Status and Development of Traditional Chemotherapy in Non-small Cell Lung Cancer under the Background of Targeted Therapy]

近年来随着非小细胞肺癌靶向治疗快速发展，传统化疗获得的关注越来越少，而如何定位并合理地应用传统化疗药物，使患者从中得到最大的获益，在当前仍是不可忽视的命题。为此，通过对相关文献的回顾和分析，本文指出无论有无驱动基因突变的患者，传统化疗仍有许多不可替代之处，并且演变出了一些新的治疗模式，进一步提高了患者的生存获益，从而明确了靶向治疗背景下传统化疗的地位。同时通过对化疗疗效预测分子标志物研究和发展的阐述，指出未来传统化疗必将“靶向化”的发展方向。

Tubb3 regulation by the Erk and Akt signaling pathways: a mechanism involved in the effect of arginine ADP-ribosyltransferase 1 (Art1) on apoptosis of colon carcinoma CT26 cells

The influence of the most important classical mono-ADP-ribosyltransferase, arginine ADP-ribosyltransferase 1 (Art1), on survival and apoptosis of colon carcinoma cells and the potential mechanisms have been partly discussed in our previous study but still need to be further studied. In this present study, Art1 of colon carcinoma CT26 cells was silenced with lentiviral vector-mediated short hairpin RNA (shRNA) or overexpressed with lentiviral vector-mediated complementary DNA (cDNA) and allograft transplant tumors are established in Balb/c mice. We verified Art1 knockdown increases apoptosis of CT26 cells transplant tumor; Art1 overexpression acts oppositely. Accordingly, growth of transplant tumors is inhibited in Art1 knockdown transplant tumors and increases in Art1 overexpression transplant tumors. Furthermore, activity of Akt and Erk cell signal pathways and expression of an apoptosis biomarker, βIII-tubulin (Tubb3), decrease when Art1 was silenced and increase when Art1 was overexpressed. Inhibiting Akt pathway or Erk pathway both downregulates expression of Tubb3 on protein and messenger RNA (mRNA) level, indicating that Tubb3 could be regulated by both Akt and Erk pathways, and plays a role in the influence of Art1 on apoptosis of Balb/c mice allograft transplant tumor. We also demonstrated that Bcl-2 family is not the responsible downstream factor of the Erk pathway in colon carcinoma cells which is undergoing apoptosis. These findings enrich the molecular mechanism for the function of Art1 in colon carcinoma and provide a complementary support for Art1 to be a potential therapeutic target of the treatment of this kind of malignant tumor.

Multinational Randomized Phase III Trial With or Without Consolidation Chemotherapy Using Docetaxel and Cisplatin After Concurrent Chemoradiation in Inoperable Stage III Non-Small-Cell Lung Cancer: KCSG-LU05-04

PURPOSE

To determine the efficacy of consolidation chemotherapy (CC) with docetaxel and cisplatin (DP) after concurrent chemoradiotherapy (CCRT) with the same agents in locally advanced non-small-cell lung cancer (LA-NSCLC).

PATIENT AND METHODS

Patients were randomly assigned to either CCRT alone (observation arm) or CCRT followed by CC (consolidation arm). CCRT with docetaxel (20 mg/m(2)) and cisplatin (20 mg/m(2)) was administered every week for 6 weeks with a total dose of 66 Gy of thoracic radiotherapy in 33 fractions. In the consolidation arm, patients were further treated with three cycles of DP (35 mg/m(2) each on days 1 and 8, every 3 weeks). The primary end point was 40% improvement in progression-free survival (PFS) compared with observation.

RESULTS

From October 2005 to April 2011, 437 patients were randomly assigned. Seventeen patients did not start CCRT as a result of consent withdrawal or ineligibility reasons after random assignment, leaving 420 patients for this analysis (n = 211 for observation; n = 209 for consolidation). Patient characteristics were similar in both arms. In the consolidation arm, 143 patients (68%) received CC, of whom 88 (62%) completed three planned cycles. The median PFS was 8.1 months in the observation arm and 9.1 months in the consolidation arm (hazard ratio, 0.91; 95% CI, 0.73 to 1.12; P = .36). Median overall survival times were 20.6 and 21.8 months in the observation and consolidation arms, respectively (HR, 0.91; 95% CI, 0.72 to 1.25; P = .44).

CONCLUSION

CC with DP after CCRT with weekly DP in LA-NSCLC failed to further prolong PFS. CCRT alone should remain the standard of care.

[Down-regulated βIII-tubulin expression can reverse paclitaxel resistance in A549/taxol cells lines]

BACKGROUND

Chemotherapy drug resistance is the primary causes of death in patients with pulmonary carcinoma which make tumor recurrence or metastasis. β-tubulin is the main cell targets of anti-microtubule drug. Increased expression of βIII-tubulin has been implicated in non-small cell lung cancer (NSCLC) cell lines. To explore the relationship among the expression level of βIII-tubulin and the sensitivity of A549/Taxolcell lines to Taxol and cell cycles and cell apoptosis by RNA interference-mediated inhibition of βIII-tubulin in A549/Taxol cells.

METHODS

Three pairs of siRNA targetd βIII-tubulin were designed and prepared, which were transfected into A549/Taxol cells using LipofectamineTM 2000. We detected the expression of βIII-tubulin mRNA using Real-time fluorescence qRT-PCR. Tedhen we selected the most efficient siRNA by the expression of βIII-tubulin mRNA in transfected group. βIII-tubulin protein level were mesured by Western blot. The taxol sensitivity in transfected group were evaluated by MTT assay. And the cell apoptosis and cell cycles were determined by flow cytometry.

RESULTS

βIII-tubulin mRNA levels in A549/Taxol cells were significantly decreased in transfected grop by Real-time qRT-PCR than control groups. And βIII-tubulin siRNA-1 sequence showed the highest transfection efficiency, which was (87.73±4.87)% (P<0.01); Western blot results showed that the expressional level of BIII tublin protein was significantly down-reulated in the transfectant cells than thant in the control cells. By MTT assay, we showed that the inhibition ratio of Taxol to A549/Taxol cells transfeced was higher than that of control group (51.77±4.60)% (P<0.01). The early apoptosis rate of A549/Taxol cells in transfected group were significantly higher than that of control group (P<0.01); G2-M content in taxol group obviously increased than untreated samples by the cell cycle (P<0.05).

CONCLUSIONS

βIII-tubulin down-regulated significantly sensitized NSCLC A549/Taxol cells to Paclitaxel.

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.

Prognostic markers in lung cancer: is it ready for prime time?

Non-small cell lung cancer (NSCLC) is a heterogeneity disease and to date, specific clinical factors and tumor stage are established as prognostic markers. Nevertheless, prognosis within stage may vary significantly. During the last 3 decades, genes/proteins that drive tumor initiation and progression, such as oncogenes and tumor suppressor genes have been studied as additional potential prognostic markers. The protein markers as evaluated by immunohistochemistry (IHC) have previously dominated these studies. However, with the development of high-throughput techniques to interrogate genome wide genetic or gene expression changes, DNA (copy number and mutation) and RNA (mRNA and microRNA) based markers have more recently been studied as prognostic markers. Largely due to the heterogeneity and complexity of NSCLC, single gene markers including KRAS mutation has not been validated as strong prognostic markers. In contrast, several gene expression signatures representing mRNA levels of multiple genes have been developed and validated in multiple microarray datasets of independent patient cohorts. The salient features of these gene signatures and their potential value to predict benefit from adjuvant chemotherapy is discussed.

Prognostic and predictive biomarkers in early stage non-small cell lung cancer: tumor based approaches including gene signatures

In early stage non-small cell lung cancer (NSCLC) large randomized trials have demonstrated that in patients with radically resected disease adjuvant chemotherapy improves 5-year survival rates. However, a customization of systemic treatment is needed to avoid treatments in patients cured by surgery alone or to justify the use of adjuvant chemotherapy in high risk patients, including those in stage IA. Recently, the possibility of identifying prognostic and predictive factors related to the genetic signatures of the tumor that could affect adjuvant and neo-adjuvant treatment choices for resectable non-small cell lung cancer (NSCLC) has been of interest. This review summarizes the current status and future opportunities for clinical application of genotyping and genomic tests in early NSCLC.

Are we ready to use biomarkers for staging, prognosis and treatment selection in early-stage non-small-cell lung cancer?

Lung cancer accounts for the majority of cancer-related deaths worldwide. At present, platinum-based therapy represents the standard of care in fit stage II and IIIA non-small cell lung cancer (NSCLC) patients following surgical resection. In advanced disease, personalized chemotherapy and targeted biologic therapy based on histological and molecular tumor profiling have already shown promise in terms of optimizing treatment efficacy. While disease stage is associated with outcome and is commonly used to determine adjuvant treatment eligibility, it is known that a subset of patients with early stage disease experience shorter survival than others with the same clinicopathological characteristics. Improved methods for identifying these individuals, at or near the time of initial diagnosis, may inform the decision to pursue adjuvant therapy options. Among the numerous candidate molecular biomarkers, only few gene-expression profiling signatures provide clinically relevant information, while real-time quantitative polymerase-chain reaction (RT-qPCR) strategy involving relatively small numbers of genes offers a practical alternative with high cross-platform performance. mRNA and/or protein expression levels of excision repair cross-complementation group 1 (ERCC1), ribonucleotide reductase M subunit 1 (RRM1) and breast cancer susceptibility gene 1 (BRCA1) are among the most promising potential biomarkers for early disease and their clinical utility is currently being evaluated in randomized phase II and III clinical trials. This review describes the most promising clinicopathological and molecular biomarkers with predictive and prognostic significance in lung cancer that have been identified through advanced research and which could influence adjuvant and neoadjuvant chemotherapy decisions for operable NSCLC in routine clinical practice.

Adjuvant chemotherapy in patients with completely resected non-small cell lung cancer

Adjuvant chemotherapy has been established as a standard for patients with completely resected non-small cell lung cancer (NSCLC). Adjuvant chemotherapy increased the 5-year survival rates by 4% to 15% within randomized trials and, based on a meta-analysis of five cisplatin-based trials, by 5.4%. Adjuvant chemotherapy consists of a cisplatin-based doublet, preferentially cisplatin plus vinorelbine. Future improvements in outcome of adjuvant therapy are expected by customized chemotherapy and the integration of targeted therapies or immunotherapy.

βIII-Tubulin Regulates Breast Cancer Metastases to the Brain

Brain metastases occur in about 10% to 30% of breast cancer patients, which culminates in a poor prognosis. It is, therefore, critical to understand the molecular mechanisms underlying brain metastatic processes to identify relevant targets. We hypothesized that breast cancer cells must express brain-associated markers that would enable their invasion and survival in the brain microenvironment. We assessed a panel of brain-predominant markers and found an elevation of several neuronal markers (βIII-tubulin, Nestin, and AchE) in brain metastatic breast cancer cells. Among these neuronal predominant markers, in silico analysis revealed overexpression of βIII-tubulin (TUBB3) in breast cancer brain metastases (BCBM) and its expression was significantly associated with distant metastases. TUBB3 knockdown studies were conducted in breast cancer models (MDA-Br, GLIM2, and MDA-MB-468), which revealed significant reduction in their invasive capabilities. MDA-Br cells with suppressed TUBB3 also demonstrated loss of key signaling molecules such as β3 integrin, pFAK, and pSrc in vitro. Furthermore, TUBB3 knockdown in a brain metastatic breast cancer cell line compromised its metastatic ability in vivo, and significantly improved survival in a brain metastasis model. These results implicate a critical role of TUBB3 in conferring brain metastatic potential to breast cancer cells.

Biomarker expression and druggable gene alterations for development of an appropriate therapeutic protocol for pulmonary adenosquamous carcinoma

AIMS

Pulmonary adenosquamous carcinoma (ASC) is more aggressive than adenocarcinoma (AC) and squamous cell carcinoma (SCC). The genetic features and biomarkers of ASC are not well known. Here, we attempted to identify potential therapeutic markers for ASC.

METHODS AND RESULTS

Surgically resected ASC samples from 65 patients were analysed. We examined the expression of β III-tubulin, thymidylate synthase, breast cancer susceptibility gene 1 and ribonucleotide reductase M1 (RRM1); identified mutations in epidermal growth factor receptor (EGFR), KRAS, BRAF and HER2; and detected ALK, ROS1 and RET rearrangements. Gene amplification and expression of EGFR, human epidermal growth factor receptor 2 (HER2), fibroblast growth factor receptor-1 and MET were also examined. β III-Tubulin showed the highest expression (P = 0.002), and its expression was more frequent in the AC than in the SCC component (P = 0.013). RRM1 expression was more frequent in the SCC component (P = 0.046). EGFR and KRAS mutations were detected in both components (21.5 and 10.9%, respectively). ALK and ROS1 rearrangements and MET amplification were detected in both components in one (1.5%) case.

CONCLUSIONS

In ASC, drug response-specific gene alterations could occur in both AC and SCC components, suggesting that patients with confirmed or suspected ASC should undergo further testing for driver gene analyses.

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.

Lack of expression of TUBB3 characterizes both BCL2-positive and BCL2-negative follicular lymphoma

Follicular lymphoma is characterized by aberrant BCL2 expression, a feature that is exploited for diagnostic purposes. However, a certain percentage of follicular lymphomas might be BCL2-negative by immunohistochemistry, increasing the difficulties in differentiating them from follicular hyperplasia. The expression of TUBB3 has been recently reported as negative in a small series of follicular lymphomas. We have therefore tested a larger series, including 61 BCL2-positive and 25 BCL2-negative cases, and compared them with 61 reactive lymphoid tissues. First, a subjective score of TUBB3 staining was applied, showing that it was consistently positive in reactive germinal centers, while most follicular lymphomas were negative; in fact, only 10/61 (16%) BCL2-positive and 1/25 (4%) BCL2-negative cases showed a positive staining for TUBB3, while 58/61 (95%) of tissues with follicular hyperplasia were positive. The application of a standardized scoring system to a large number of follicles, based on virtual slides, demonstrated that reactive lymphoid tissues had a significantly higher number of TUBB3-positive follicles both compared with BCL2-positive cases and to BCL2-negative cases. Our data support the use of TUBB3 staining in differentiating follicular lymphoma, including BCL2-negative cases, from follicular hyperplasia.

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.

Immunohistochemistry evaluation of biomarker expression in non-small cell lung cancer (Pharmacogenoscan study)

OBJECTIVES

Platinum-based chemotherapy regimens are the standard treatment of non-small cell lung cancer (NSCLC). In this study, our objective was to identify tumor tissue protein biomarkers that might predict a benefit from these treatments.

MATERIALS AND METHODS

The Pharmacogenoscan study prospectively included consecutive chemotherapy-naive NSCLC patients at any stage between 2005 and 2010 at six hospitals in the Rhône-Alpes-Auvergne region of France. Of the 537 patients in the full analysis set, 460 had a complete histological diagnosis. We used the tumor tissue samples for an immunohistochemical evaluation of eight biomarkers: ERCC1, BRCA1, p53, p27kip1, class III β-tubulin (TUBB3), Bax, Fas, and FasL. We looked for associations between these biomarkers and the disease control rate (DCR) after 2/3 cycles of platinum-based chemotherapy, progression-free survival (PFS), and overall survival (OS).

RESULTS

A tissue sample adequate for testing at least one biomarker was available for 289 patients. We found no significant association between biomarker expression levels and clinical or pathological variables; TUBB3 showed a trend toward higher expression in adenocarcinomas (P=0.005). For none of the biomarkers were significant associations found between expression level and DCR, PFS, or OS. TUBB3-negative and FasL-negative tumors showed associations of borderline significance with higher DCR.

CONCLUSION

In a large cohort of patients with predominantly advanced or metastatic NSCLC, none of eight tested immunohistochemical biomarkers predicted the chemotherapy response or survival. Our data indicate limited usefulness of protein biomarkers in metastatic NSCLC and a need for further research based on molecular signatures of greater complexity.

Early-stage non-small cell lung cancer: surgery, stereotactic radiosurgery, and individualized adjuvant therapy

Despite cures in early stage (IA-IIB) non-small cell lung cancer (NSCLC), the 5-year survival rate is only 36%-73%. Surgical resection via lobectomy is the treatment of choice in early-stage NSCLC, with the goal being complete anatomic resection of the tumor and mediastinal lymph node evaluation. Newer technologies, including the minimally invasive thoracoscopic approach and the many techniques available to stage the mediastinum, have introduced advantages over traditional approaches in achieving this goal. The advent of stereotactic ablative radiotherapy (SABR) has changed how we treat those patients who cannot undergo surgery secondary to comorbidities or patient preference. SABR allows for precise radiation delivery in a short course and at high doses. Adjuvant cisplatin-based chemotherapy is the standard of care for completely resected high-risk stage IB and stage II NSCLC based on a ~5% improvement in 5-year overall survival. The concept of customized adjuvant chemotherapy is emerging, and we will explore the potential value of targeting tumor mutations with available drugs (ie, epidermal growth factor receptor [EGFR] mutations with erlotinib), a strategy that for the moment should be restricted to clinical trials.

High expression of class III β-tubulin in small cell lung carcinoma

Class III β-tubulin (TUBB3) is emerging as a biomarker in a number of cancers. TUBB3 has been shown to be a prognostic indicator of more aggressive disease and a predictor of resistance to taxanes and vinca alkaloids. To date, there is little data on TUBB3 expression in small cell lung carcinoma (SCLC). The primary objective of this study was to determine the expression of TUBB3 in SCLC. Immunohistochemical staining of SCLC tumor specimens was performed using standard procedures. Expression of TUBB3 was determined as a composite of the percentage of malignant cells staining positive and the intensity of staining. Clinical and tumor data for each patient was compared with the degree of TUBB3 expression. A total of 66 SCLCs were evaluable for TUBB3 expression. The majority of specimens (n=56, 85%) had high expression of TUBB3. Only 4.5% (n=3) had low expression of TUBB3. The mean distribution of positive staining for the specimens was 87.3±1.8% (mean ± SE). Specimens from core biopsies were significantly more likely to have high TUBB3 expression when compared with fine needle aspirates (P=0.004). There were no other significant findings when comparing clinical or tumor characteristics. Overall, we found that expression of TUBB3 in SCLC is higher than expected. Innate resistance to microtubule inhibitors, such as the taxanes and vinca alkaloids, may be associated with this finding. Attempts at microtubule inhibition with novel agents may be able to overcome this resistance mechanism. Further evaluation of TUBB3 as a biomarker in SCLC is warranted.

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

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

Adjuvant treatment in resected non-small cell lung cancer: current and future issues

The cornerstone of treatment for early-stage non-small cell lung cancer (NSCLC) has been surgical resection. In the last five years two phase III trials have provided evidence of adjuvant platinum-based chemotherapy for completely resected stage II-IIIA patients. We review the evidence supporting adjuvant therapy in early-stage NSCLC; we discuss new issues surrounding adjuvant therapy such as treatment in the elderly-unfit population, treatment toxicity and its influence on outcomes, the importance of histology and gender in adjuvant treatment; and we discuss the future landscape of early-stage NSCLC research, namely, therapeutic strategies exploiting pharmacogenomic and gene-expression profiling, in an attempt to customize the treatment.

Adjuvant chemotherapy after pulmonary resection for lung cancer

Adjuvant chemotherapy using a cisplatin-based regimen is currently recommended for patients with stage II and III non-small cell lung cancer (NSCLC) after complete tumor resection and may be considered for patients with stage IB NSCLC. Although adjuvant chemotherapy after complete resection of localized NSCLC is associated with an absolute survival advantage of approximately 5% at 5 years, there is still a relatively high risk of relapse even for early-stage NSCLC. Efforts are ongoing to identify new treatments in the adjuvant setting and to select patients for individualized treatment based on biomarkers.

High expression levels of class III β-tubulin in resected non-small cell lung cancer patients are predictive of improved patient survival after vinorelbine-based adjuvant chemotherapy

The aim of the present study was to determine the frequency and predictive value of the expression of tumor microtubule components in patients with resected non-small cell lung cancer (R-NSCLC) subsequently treated with vinorelbine-based adjuvant chemotherapy. The expression of the microtubule components was evaluated in 85 R-NSCLC tumor samples using immunohistochemistry. All patients received vinorelbine-based chemotherapy. The predictive value of microtubule protein expression for disease-free survival (DFS) and overall survival (OS) was assessed. The expression of the microtubule components was not associated with any baseline clinicopathological factors in the R-NSCLC patients. High tumor expression levels of class III β-tubulin were correlated with an improved DFS (P=0.033) and a trend towards a longer OS (P=0.226). Class II and IV β-tubulins were not correlated with patient outcome. Multivariate analysis of factors, including gender, age, histology, stage and class II, III and IV β-tubulin expression demonstrated that high levels of class III β-tubulin expression were correlated independently with DFS (P= 0.031). These findings suggest that high class III β-tubulin expression levels in resected tumors are predictive of improved DFS in R-NSCLC patients receiving vinorelbine-based chemotherapy.

Correlation between microtubule-associated gene expression and chemosensitivity of patients with stage II non-small cell lung cancer

The aim of this study was to explore the correlation between mRNA expression of β-tubulin-III and stathmin in patients with stage II non-small cell lung cancer (NSCLC) and the chemosensitivity to Navelbine plus cisplatin (NP), as well as to provide a basis for personalized treatment. A single-gene quantitative test was performed to detect the mRNA expression of β-tubulin-III and stathmin in the tumor tissue of patients with stage II NSCLC. All the patients underwent NP treatment following surgery and were followed-up to record their disease-free survival (DFS) and overall survival (OS). Statistical analyses were conducted to investigate the correlation between β-tubulin-III and stathmin mRNA expression and DFS and OS in the patients. β-tubulin-III mRNA expression was associated with OS in the 73 patients (P=0.003) and DFS was correlated with β-tubulin-III mRNA expression and lymphatic metastasis (P<0.01). Stathmin mRNA expression was not correlated with OS or DFS (P>0.05). OS and DFS were longer in the patients with low β-tubulin-III mRNA expression than in those with high β-tubulin-III mRNA expression (P<0.01); there was no significant change in OS and DFS between the patients with high and low mRNA expression of stathmin (P>0.05). The mRNA expression levels of β-tubulin-III in the tumor tissue of patients with stage II NSCLC may be considered as an index of prognosis and chemosensitivity, as well as a reference for personalized chemotherapeutic applications in patients.

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.

High expression of class III β-tubulin predicts good response to neoadjuvant taxane and doxorubicin/cyclophosphamide-based chemotherapy in estrogen receptor-negative breast cancer

BACKGROUND

Expression of class ΙΙΙ β-tubulin (βΙΙΙ-tubulin) correlates with tumor progression and resistance to taxane-based therapies for several human malignancies including breast cancer. However its predictive value in a neoadjuvant setting in breast cancer remains unexplored. The objective of this explorative study was to determine whether βΙΙΙ-tubulin expression in breast cancer correlated with pathologic characteristics and whether its expression was predictive of response to neoadjuvant chemotherapy.

PATIENTS AND METHODS

We determined βΙΙΙ-tubulin expression in 85 breast cancers, including 41 localized breast cancers treated with primary surgery and 44 treated with neoadjuvant chemotherapy before surgery. βΙΙΙ-tubulin expression was evaluated by immunohistochemical methods and was correlated with pathologic characteristics and response to neoadjuvant chemotherapy using residual cancer burden (RCB) score.

RESULTS

High βΙΙΙ-tubulin expression was significantly associated with poorly differentiated high-grade breast cancers (P = .003) but not with tumor size, estrogen receptor (ER) status, or human epidermal growth factor receptor 2 (HER2)/neu overexpression. In ER(-) tumors treated with neoadjuvant chemotherapy, high βΙΙΙ-tubulin expression was associated with a significantly greater likelihood of achieving a good pathologic response to chemotherapy as reflected by lower RCB scores (P = .021).

CONCLUSION

This study reveals differential βΙΙΙ-tubulin expression in breast cancers of different histologic grades, hormone receptors, and HER2/neu status. It also suggests a potential role for βΙΙΙ-tubulin as a predictive biomarker for response in neoadjuvant chemotherapy for ER(-) breast cancer, which has not been previously reported. These data provide a strong rationale for considering βΙΙΙ-tubulin status and further validation of this marker in a large study.