Topoisomerase IIalpha and other drug resistance markers in advanced non-small cell lung cancer

Identifying General Tumor and Specific Lung Cancer Biomarkers by Transcriptomic Analysis

The bioinformatic pipeline previously developed in our research laboratory is used to identify potential general and specific deregulated tumor genes and transcription factors related to the establishment and progression of tumoral diseases, now comparing lung cancer with other two types of cancer. Twenty microarray datasets were selected and analyzed separately to identify hub differentiated expressed genes and compared to identify all the deregulated genes and transcription factors in common between the three types of cancer and those unique to lung cancer. The winning DEGs analysis allowed to identify an important number of TFs deregulated in the majority of microarray datasets, which can become key biomarkers of general tumors and specific to lung cancer. A coexpression network was constructed for every dataset with all deregulated genes associated with lung cancer, according to DAVID’s tool enrichment analysis, and transcription factors capable of regulating them, according to oPOSSUM´s tool. Several genes and transcription factors are coexpressed in the networks, suggesting that they could be related to the establishment or progression of the tumoral pathology in any tissue and specifically in the lung. The comparison of the coexpression networks of lung cancer and other types of cancer allowed the identification of common connectivity patterns with deregulated genes and transcription factors correlated to important tumoral processes and signaling pathways that have not been studied yet to experimentally validate their role in lung cancer. The Kaplan–Meier estimator determined the association of thirteen deregulated top winning transcription factors with the survival of lung cancer patients. The coregulatory analysis identified two top winning transcription factors networks related to the regulatory control of gene expression in lung and breast cancer. Our transcriptomic analysis suggests that cancer has an important coregulatory network of transcription factors related to the acquisition of the hallmarks of cancer. Moreover, lung cancer has a group of genes and transcription factors unique to pulmonary tissue that are coexpressed during tumorigenesis and must be studied experimentally to fully understand their role in the pathogenesis within its very complex transcriptomic scenario. Therefore, the downstream bioinformatic analysis developed was able to identify a coregulatory metafirm of cancer in general and specific to lung cancer taking into account the great heterogeneity of the tumoral process at cellular and population levels.

Joint Transcriptomic Analysis of Lung Cancer and Other Lung Diseases

Background: Epidemiological and clinical evidence points cancer comorbidity with pulmonary chronic disease. The acquisition of some hallmarks of cancer by cells affected with lung pathologies as a cell adaptive mechanism to a shear stress, suggests that could be associated with the establishment of tumoral processes. Objective: To propose a bioinformatic pipeline for the identification of all deregulated genes and the transcriptional regulators (TFs) that are coexpressed during lung cancer establishment, and therefore could be important for the acquisition of the hallmarks of cancer. Methods: Ten microarray datasets (six of lung cancer, four of lung diseases) comparing normal and diseases-related lung tissue were selected to identify hub differentiated expressed genes (DEGs) in common between lung pathologies and lung cancer, along with transcriptional regulators through the utilization of specialized libraries from R language. DAVID bioinformatics tool for gene enrichment analyses was used to identify genes with experimental evidence associated to tumoral processes and signaling pathways. Coexpression networks of DEGs and TFs in lung cancer establishment were created with Coexnet library, and a survival analysis of the main hub genes was made. Results: Two hundred ten DEGs were identified in common between lung cancer and other lung diseases related to the acquisition of tumoral characteristics, which are coexpressed in a lung cancer network with TFs, suggesting that could be related to the establishment of the tumoral pathology in lung. The comparison of the coexpression networks of lung cancer and other lung diseases allowed the identification of common connectivity patterns (CCPs) with DEGs and TFs correlated to important tumoral processes and signaling pathways, that haven´t been studied to experimentally validate their role in the early stages of lung cancer. Some of the TFs identified showed a correlation between its expression levels and the survival of lung cancer patients. Conclusion: Our findings indicate that lung diseases share genes with lung cancer which are coexpressed in lung cancer, and might be able to explain the epidemiological observations that point to direct and inverse comorbid associations between some chronic lung diseases and lung cancer and represent a complex transcriptomic scenario.

Promoter polymorphisms of TOP2A and ERCC1 genes as predictive factors for chemotherapy in non-small cell lung cancer patients

Background

Topoisomerase 2‐alpha (TOP2A) is an enzyme that controls topologic changes in DNA during transcription and replication. ERCC1 is an enzyme that takes part in DNA repair processes. The purpose of this study was to assess the predictive role of particular single nucleotide polymorphisms (SNPs) in the promoter regions of TOP2A and ERCC1 genes in non‐small cell lung cancer patients (NSCLC) treated with chemotherapy.

Materials and methods

We enrolled 113 NSCLC patients treated in the first line with platinum‐based chemotherapy. Effectiveness was available for 71 patients. DNA was isolated from whole blood using the Qiamp DNA Blood Mini kit (Qiagen). We examined five SNPs: rs11615 (ERCC1), rs3212986 (ERCC1), rs13695 (TOP2A), rs34300454 (TOP2A), rs11540720 (TOP2A). Quantitative PCR using the TaqMan probe (ThermoFisher) was performed on a Eco Illumina Real‐Time PCR system device (Illumina Inc).

Results

Patients with the A/A genotype in rs11615 of the ERCC1 gene had significantly longer median progression free survival (PFS) (8.5 months; P = .0088). Patients with the C/C genotype in rs3212986 of the ERCC1 gene had longer median PFS (7 months; P = .05). Patients with the C/C genotype in rs34300454 of TOP2A gene had significantly higher median PFS (7.5 months; P = .0029). Carriers of the C/C genotype in rs34300454 of the TOP2A gene had significantly longer median OS (15.5 months; P = .0017). Patients with the A/A genotype in rs11615 of the ERCC1 gene had significantly higher risk of neutropenia (P = .0133).

Conclusions

Polymorphisms of the TOP2A and ERCC1 genes may be a predictive factor of toxicities and survival for chemotherapy in NSCLC patients.

Comprehensive analysis of non-small-cell lung cancer microarray datasets identifies several prognostic biomarkers

Aim: To find accurate and effective biomarkers for diagnosis of non-small-cell lung cancer (NSCLC) patients. Materials & methods: We downloaded microarray datasets GSE19188, GSE33532, GSE101929 and GSE102286 from the database of Gene Expression Omnibus. We screened out differentially expressed genes (DEGs) and miRNAs (DEMs) with GEO2R. We also performed analyses for the enrichment of DEGs' and DEMs' function and pathway by several tools including database for annotation, visualization and integrated discovery, protein-protein interaction and Kaplan-Meier-plotter. Results: Total 913 DEGs were screened out, among which ten hub genes were discovered. All the hub genes were linked to the worsening overall survival of the NSCLC patients. Besides, 98 DEMs were screened out. MiR-9 and miR-520e were the most significantly regulated miRNAs. Conclusion: Our results could provide potential targets for the diagnosis and treatment of NSCLC.

Proteomic and Bioinformatic Studies for the Characterization of Response to Pemetrexed in Platinum Drug Resistant Ovarian Cancer

Proteomics and bioinformatics are a useful combined technology for the characterization of protein expression level and modulation associated with the response to a drug and with its mechanism of action. The folate pathway represents an important target in the anticancer drugs therapy. In the present study, a discovery proteomics approach was applied to tissue samples collected from ovarian cancer patients who relapsed after the first-line carboplatin-based chemotherapy and were treated with pemetrexed (PMX), a known folate pathway targeting drug. The aim of the work is to identify the proteomic profile that can be associated to the response to the PMX treatment in pre-treatement tissue. Statistical metrics of the experimental Mass Spectrometry (MS) data were combined with a knowledge-based approach that included bioinformatics and a literature review through ProteinQuest™ tool, to design a protein set of reference (PSR). The PSR provides feedback for the consistency of MS proteomic data because it includes known validated proteins. A panel of 24 proteins with levels that were significantly different in pre-treatment samples of patients who responded to the therapy vs. the non-responder ones, was identified. The differences of the identified proteins were explained for the patients with different outcomes and the known PMX targets were further validated. The protein panel herein identified is ready for further validation in retrospective clinical trials using a targeted proteomic approach. This study may have a general relevant impact on biomarker application for cancer patients therapy selection.

The Novel Triazolonaphthalimide Derivative LSS-11 Synergizes the Anti-Proliferative Effect of Paclitaxel via STAT3-Dependent MDR1 and MRP1 Downregulation in Chemoresistant Lung Cancer Cells

Multidrug resistance (MDR) is a major cause of the inefficacy and poor response to paclitaxel-based chemotherapy. The combination of conventional cytotoxic drugs has been a plausible strategy for overcoming paclitaxel resistance. Herein, we investigated the cytotoxic effects and underlying mechanism of LSS-11, a novel naphthalimide derivative-based topoisomerase inhibitor, in paclitaxel-resistant A549 (A549/T) lung cancer cells. LSS-11 enhanced cell death in A549/T cells by inducing apoptosis through increasing the DR5 protein level and PARP1 cleavage. Importantly, LSS-11 dose-dependently reduced STAT3 phosphorylation and downregulated its target genes MDR1 and MRP1, without affecting P-gp transport function. Chromatin coimmunoprecipitation (ChIP) assay further revealed that LSS-11 hindered the binding of STAT3 to the MDR1 and MRP1 promoters. Additionally, pharmacological inhibition of p-STAT3 by sulforaphane downregulated MDR1 and MRP1, resulting in A549/T cell death by triggering apoptosis. Collectively, our data show that LSS-11 is a potent naphthalimide-based chemosensitizer that could enhance cell death in paclitaxel-resistant lung cancer cells through the DR5/PARP1 pathway and STAT3/MDR1/MRP1 STAT3 inhibition.

Correlations of ICAM-1 gene polymorphisms with susceptibility and multidrug resistance in colorectal cancer in a Chinese population

BACKGROUND

Colorectal cancer (CRC) is a malignant gastrointestinal tumor with a high mortality rate, including both colon and rectal cancer. In order to provide clinical guidance for the treatment of CRC, this study is conducted to investigate the correlations of intercellular adhesion molecule 1 (ICAM-1) gene polymorphisms with susceptibility and multidrug resistance (MDR) of colorectal cancer (CRC).

METHODS

A total of 195 patients with CRC were selected as the observation group and 188 healthy people enrolled as the control group. Polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) was used to test ICAM-1 A13848G and K469E polymorphisms. The expressions of MDR-associated protein topoisomerase II (Topo II) and P-glycoprotein (P-gp) in CRC tissues were detected by immunohistochemistry. The analysis on association of clinical indexes of CRC patients with ICAM-1 gene polymorphisms was performed.

RESULTS

The frequencies of KK genotype and K allele of K469E in the observation group were significantly higher than that in the control group. KE + EE genotype and E allele might be protective factors for CRC. The distribution of genotypes, K469E KK and KE+EE, was highly correlated with histologic grade of tumor differentiation. Compared with adjacent normal tissues, positive rates of Topo II and P-gp expression were significantly increased in CRC tissues. Topo II expression in CRC patients was positively associated with lymph node metastasis and depth of tumor invasion, whereas P-gp expression was only associated with depth of tumor invasion. Higher positive rates of Topo II and P-gp expression were observed in ICAM-1 K469E KK genotype carriers, indicating that ICAM-1 K469E KK genotype might be related to MDR in CRC.

CONCLUSION

These findings in the current study suggested that ICAM-1 K469E polymorphism is highly correlated with susceptibility and MDR in CRC.

Prognostic effect of class III β-tubulin and Topoisomerase-II in patients with advanced thymic carcinoma who received combination chemotherapy, including taxanes or topoisomerase-II inhibitors

Class III β-tubulin (TUBB3) and Topoisomerase-II (topo-II) are considered to be the predictors of therapeutic efficacy and outcome in several types of human neoplasm. However, whether TUBB3 or topo-II may predict the response to combination chemotherapy and prognosis in patients with advanced thymic carcinoma (ATC) remains unclear. The aim of the present study was to investigate the prognostic significance of TUBB3 and topo-II expression levels in ATC. A total of 34 patients with ATC who received combination chemotherapy were enrolled in the present study. Immunohistochemical analysis was used to examine the expression of TUBB3, topo-II and Ki-67 in tumor specimens obtained by surgical resection or biopsy. TUBB3 and topo-II were highly expressed in 38 and 53% of the tumors, respectively. Progression-free survival (PFS) was significantly shorter in patients with high levels of TUBB3 compared with those with low levels of TUBB3 (P<0.01), whereas no significant difference in PFS between patients with high and low topo-II expression levels was observed (P=0.31). Patients with overexpression of TUBB3 or topo-II exhibited significantly shorter overall survival rates (OS) compared with those patients with low levels of expression of these proteins (TUBB3; P=0.01, topo-II; P=0.01). Multivariate analysis demonstrated that a high level of TUBB3 expression was an independent unfavorable prognostic factor for OS, and a high level of topo-II expression tended to correlate with poor prognosis without statistical significance. Additionally, a subset analysis demonstrated that the treatment with taxanes, but not topo-II inhibitors, tended to prolong OS in patients with TUBB3 overexpression and there was significant survival advantage of chemoradiotherapy over chemotherapy in patients with topo-II overexpression. It was revealed that an enhanced expression of TUBB3 or topo-II was clearly associated with clinical outcomes in patients with ATC who received combination chemotherapy, including taxanes or topo-II inhibitors, suggesting the prognostic significance of these markers.

Mining expression and prognosis of topoisomerase isoforms in non-small-cell lung cancer by using Oncomine and Kaplan-Meier plotter

DNA topoisomerases are essential to modulate DNA topology during various cellular genetic processes. The expression and distinct prognostic value of topoisomerase isoforms in non-small-cell lung cancer (NSCLC) is not well established. In the current study, we have examined the mRNA expression of topoisomerase isoforms by using Oncomine analysis and investigated their prognostic value via the Kaplan–Meier plotter database in NSCLC patients. Our analysis indicated that the expression level of topoisomerases in lung cancer was higher compared with normal tissues. Especially, high expression of two topoisomerase isoforms, TOP2A and TOP3A, was found to be correlated to worse overall survival (OS) in all NSCLC and lung adenocarcinoma (Ade) patients, but not in lung squamous cell carcinoma (SCC) patients. In a contrast, high expression of isoforms TOP1 and TOP2B indicated better OS in all NSCLC and Ade, but not in SCC patients. Meanwhile, high expression of TOP1MT and TOP3B was not correlated with OS in NSCLC patients. Furthermore, we also demonstrated a relationship between topoisomerase isoforms and the clinicopathological features for the NSCLC patients, such as grades, clinical stages, lymph node status, smoking status, gender, chemotherapy and radiotherapy. These results support that TOP2A and TOP3A are associated with worse prognosis in NSCLC patients. In addition, our study also shows that TOP1 and TOP2B contribute to favorable prognosis in NSCLC patients. The exact prognostic significance of TOP1MT and TOP3B need to be further elucidated. Comprehensive evaluation of expression and prognosis of topoisomerase isoforms will be a benefit for the better understanding of heterogeneity and complexity in the molecular biology of NSCLC, paving a way for more accurate prediction of prognosis and discovery of potential drug targets for NSCLC patients.

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.

Prognostic implications of survivin and lung resistance protein in advanced non-small cell lung cancer treated with platinum-based chemotherapy

Platinum-based chemotherapy is the first-line treatment for non-small cell lung cancer (NSCLC), but the chemotherapy often results in the development of chemoresistance. The present study aimed to explore the prognostic implications of survivin and lung resistance protein (LRP) in advanced NSCLC treated with platinum-based chemotherapy. Tumor samples were collected from 61 hospitalized patients with stage IIIB-IV NSCLC that underwent platinum-based chemotherapy. All patient samples were collected in the Oncology Department of the Third Affiliated Hospital of Guangxi Medical University between January 2006 and January 2011. Cytoplasmic survivin and LRP expression were evaluated using immunohistochemistry. The expression of LRP and survivin reached 77% (47/61) and 76% (45/61), respectively. Positive expression of survivin was associated with a lower median progression-free survival (PFS) time (4 vs. 9 months; P=0.038) and a lower median overall survival (OS) time compared with the absence of survivin expression (9 vs. 16 months; P=0.039). Patients with LRP and survivin expression (n=41) demonstrated a median PFS time of 4 months. However, patients with either LRP or survivin expression (n=10) demonstrated a median PFS time of 8 months, which is similar to the median PFS time of the 10 patients with no expression of LRP and survivin (9 months; P=0.022). Either the expression of survivin or the combined expression of LRP and survivin is associated with a poor prognosis in advanced NSCLC treated with platinum-based chemotherapy.

Markers of response to platinum-based chemotherapy in lung cancer

SUMMARY Non-small-cell lung cancer (NSCLC) is the most common cause of cancer-related deaths among men and women worldwide. Despite the development of molecular targeted therapies, platinum-based combination chemotherapy remains the most effective systemic chemotherapy for NSCLC patients. Unfortunately, the outcomes of platinum-based therapies, in particular those containing cisplatin, have reached a plateau due to the development of both intrinsic and acquired resistance. While significant variations in response to platinum-based chemotherapeutic regimens exist, defining molecular features that may determine resistance or response to chemotherapy is critical. This review will focus on some of the emerging biomarkers that are predictive of response to such treatments that may offer potential in the future management of NSCLC patients.

Clinical impact of ki-67 labeling index in non-small cell lung cancer

The ki-67 index is a marker of proliferation in malignant tumors. Studies from the period 2000 to 2012 on the prognostic and predictive value of ki-67 labeling index (LI) in non-small cell cancer (NSCLC) are reviewed. Twenty-eight studies reported on the prognostic value of ki-67 index with various endpoints. No consensus on the prognostic value of ki-67 LI was found among the published studies neither according to disease stage nor histological subtype. Comparison of studies is hampered by differences in patient populations, methodologies and cut-off values. Five studies explored the predictive value of ki-67 to chemotherapy and none revealed significant influence. Ki-67 index seems to be of prognostic influence in NSCLC although largely variable cut-off levels have been used in the various studies and standardization of methodology is required. The relative importance of ki-67 compared to newer biomarkers has not been explored. It is likely that a signature of several biomarkers in combination may be necessary to more sufficiently stratify patients to various treatment options than is currently possible, especially when it comes to the question of the optimal use of classical chemotherapy. A predictive impact of ki-67 to treatment in NSCLC remains unclear.

Topo IIα gene alterations correlated with survival in patients with diffuse large B-cell lymphoma

BACKGROUND

Topoisomerase IIα (topo IIα) protein expression has prognostic significance in many cancers. However, it is still unclear whether topo IIα protein expression and gene alterations play roles as prognostic factors in diffuse large B-cell lymphoma (DLBCL).

MATERIALS AND METHODS

We selected 102 patients with DLBCL who were homogeneously treated with CHOP chemotherapy and followed up. Using tissue microarray technology, all of the cases, consisting of 25 germinal centre B-cell-like (GCB) and 77 nongerminal centre B-cell-like (non-GCB) types, were studied. Topo IIα protein expression was detected by immunohistochemistry. Gene copy number of topo IIα was analysed by chromogenic in situ hybridization. Cox regression, chi-square test and Kaplan-Meier statistics were performed using SPSS 15·0.

RESULTS

Topo IIα protein overexpression was found in 91 (91/102, 89·2%) cases, while topo IIα gene amplification was absent in all cases. Chromosome 17 deletion was identified in 3 (3/102, 2·9%) cases, diploid in 66 (66/102, 64·7%) cases and aneuploidy in 33 (33/102, 32·4%) cases. By multivariate analysis, no significant differences in progression-free survival (PFS) and overall survival (OS) were observed in patients with topo IIα protein overexpression (P > 0·05), while chromosome 17 aneuploidy predicted worse PFS and OS (P < 0·001).

CONCLUSIONS

These results suggested that chromosome 17 aneuploidy, but not topo IIα protein expression, could predict worse survival in patients with DLBCL.

Overexpression of centrosomal protein Nlp confers breast carcinoma resistance to paclitaxel

Nlp (ninein-like protein), an important molecule involved in centrosome maturation and spindle formation, plays an important role in tumorigenesis and its abnormal expression was recently observed in human breast and lung cancers. In this study, the correlation between overexpression of Nlp and paclitaxel chemosensitivity was investigated to explore the mechanisms of resistance to paclitaxel and to understand the effect of Nlp upon apoptosis induced by chemotherapeutic agents. Nlp expression vector was stably transfected into breast cancer MCF-7 cells. With Nlp overexpression, the survival rates, cell cycle distributions and apoptosis were analyzed in transfected MCF-7 cells by MTT test and FCM approach. The immunofluorescent assay was employed to detect the changes of microtubule after paclitaxel treatment. Immunoblotting analysis was used to examine expression of centrosomal proteins and apoptosis associated proteins. Subsequently, Nlp expression was retrospectively examined with 55 breast cancer samples derived from paclitaxel treated patients. Interestingly, the survival rates of MCF-7 cells with Nlp overexpressing were higher than that of control after paclitaxel treatment. Nlp overexpression promoted G2-M arrest and attenuated apoptosis induced by paclitaxel, which was coupled with elevated Bcl-2 protein. Nlp expression significantly lessened the microtubule polymerization and bundling elicited by paclitaxel attributing to alteration on the structure or dynamics of β-tubulin but not on its expression. The breast cancer patients with high expression of Nlp were likely resistant to the treatment of paclitaxel, as the response rate in Nlp negative patients was 62.5%, whereas was 58.3 and 15.8% in Nlp (+) and Nlp (++) patients respectively (p = 0.015). Nlp expression was positive correlated with those of Plk1 and PCNA. These findings provide insights into more rational chemotherapeutic regimens in clinical practice, and more effective approaches might be developed through targeting Nlp to increase chemotherapeutic sensitivity.

Topoisomerase II alpha expression and the benefit of adjuvant chemotherapy for postoperative patients with non-small cell lung cancer

Background

Adjuvant chemotherapy has been shown to improve survival rates of postoperative patients with non-small cell lung cancer (NSCLC). Biomarkers could help select an appropriate chemotherapy for NSCLC patients or predict the efficacy of chemotherapy. The objective of this study was to explore the possible prognostic and predictive role of topoisomerase II alpha (TopIIα) expression level in postoperative NSCLC patients who received adjuvant chemotherapy.

Methods

Patients with stage I-III NSCLC, who underwent surgery in our hospital from January 2004 to December 2007 and who also received adjuvant chemotherapy after surgery, were analyzed in this study. Expression of TopIIα and Ki67 in paraffin-embedded tissues was detected by immunohistochemistry (IHC). The relationships between clinicopathological characteristics, chemotherapy regimens, the expression of biomarkers and disease free survival (DFS) were analyzed.

Results

TopIIα and Ki67 were highly expressed in 22.5% and 36.4% of the 151 patients, respectively. Univariate survival analysis showed that male sex (P = 0.036), non-adenocarcinoma (P = 0.004), earlier pathological TNM stage (P = 0.001) or pathological N stage (P < 0.001), and high expression of TopIIα (P = 0.012) were correlated with better DFS, whereas age, smoking history, different chemotherapy regimens, T stage and expression level of Ki67 were of no prognostic significance. Further stratified analysis showed that vinorelbine (NVB)-containing adjuvant regimens were generally associated with better DFS than regimens without NVB in patients with low TopIIα expression, though the difference was not statistically significant (P = 0.065). Pairwise comparisons for patients with low TopIIα expression indicated that the NVB-containing regimen was associated with better DFS than the docetaxel (TXT)-containing regimen (P = 0.047). COX multivariate analysis showed that pathological TNM stage, histological subtype and expression level of TopIIα to be independent of risk factors affecting DFS in postoperative NSCLC patients who received chemotherapy.

Conclusions

High TopIIα expression was discovered to be correlated with better DFS for postoperative NSCLC patients who received adjuvant chemotherapy. The NVB-containing chemotherapy regimen was more effective than the TXT-containing regimen in improving DFS in patients with low TopIIα expression. TopIIα could be considered to be an independent prognostic biomarker of DFS in postoperative NSCLC patients who received adjuvant chemotherapy.

Tumor and host factors that may limit efficacy of chemotherapy in non-small cell and small cell lung cancer

While chemotherapy provides useful palliation, advanced lung cancer remains incurable since those tumors that are initially sensitive to therapy rapidly develop acquired resistance. Resistance may arise from impaired drug delivery, extracellular factors, decreased drug uptake into tumor cells, increased drug efflux, drug inactivation by detoxifying factors, decreased drug activation or binding to target, altered target, increased damage repair, tolerance of damage, decreased proapoptotic factors, increased antiapoptotic factors, or altered cell cycling or transcription factors. Factors for which there is now substantial clinical evidence of a link to small cell lung cancer (SCLC) resistance to chemotherapy include MRP (for platinum-based combination chemotherapy) and MDR1/P-gp (for non-platinum agents). SPECT MIBI and Tc-TF scanning appears to predict chemotherapy benefit in SCLC. In non-small cell lung cancer (NSCLC), the strongest clinical evidence is for taxane resistance with elevated expression or mutation of class III beta-tubulin (and possibly alpha tubulin), platinum resistance and expression of ERCC1 or BCRP, gemcitabine resistance and RRM1 expression, and resistance to several agents and COX-2 expression (although COX-2 inhibitors have had minimal impact on drug efficacy clinically). Tumors expressing high BRCA1 may have increased resistance to platinums but increased sensitivity to taxanes. Limited early clinical data suggest that chemotherapy resistance in NSCLC may also be increased with decreased expression of cyclin B1 or of Eg5, or with increased expression of ICAM, matrilysin, osteopontin, DDH, survivin, PCDGF, caveolin-1, p21WAF1/CIP1, or 14-3-3sigma, and that IGF-1R inhibitors may increase efficacy of chemotherapy, particularly in squamous cell carcinomas. Equivocal data (with some positive studies but other negative studies) suggest that NSCLC tumors with some EGFR mutations may have increased sensitivity to chemotherapy, while K-ras mutations and expression of GST-pi, RB or p27kip1 may possibly confer resistance. While limited clinical data suggest that p53 mutations are associated with resistance to platinum-based therapies in NSCLC, data on p53 IHC positivity are equivocal. To date, resistance-modulating strategies have generally not proven clinically useful in lung cancer, although small randomized trials suggest a modest benefit of verapamil and related agents in NSCLC.

Topoisomerase IIalpha mRNA and protein expression in ovarian carcinoma: correlation with clinicopathological factors and prognosis

Topoisomerase IIalpha (Top IIalpha) is a nuclear enzyme that plays a central role in DNA metabolism, and is a molecular target for a variety of chemotherapeutic agents. Top IIalpha has recently gained attention as a biomarker for therapy response and patient survival. In this study, we attempted to assess the feasibility of measuring Top IIalpha gene expression in RNA, isolated from archival formalin-fixed paraffin-embedded tissue specimens, which are used routinely in pathology laboratories. We have employed a new technique on the basis of magnetic particles' separation and purification of nucleic acids, and evaluated both protein and mRNA expressions from the same routinely processed tissue blocks. We investigated the expression of Top IIalpha mRNA and protein by real-time reverse transcription polymerase chain reaction and immunohistochemistry, in a cohort of 133 primary ovarian carcinomas, and evaluated the association between Top IIalpha expression and clincopathological variables as well as patient outcome. Elevated Top IIalpha mRNA expression was observed in high-grade tumors (P=0.003) and advanced stage disease (P=0.011). In univariate Kaplan-Meier analysis, patients with higher expression of Top IIalpha nuclear protein had a significantly decreased overall survival (P=0.045). Interestingly, we detected cytoplasmic protein expression of Top IIalpha in a subset of samples. Cytoplasmic expression of Top IIalpha was associated with the expression of chromosomal region maintenance/exportin 1 (CRM1)-a nuclear export protein (P=0.008). Our study suggests that Top IIalpha overexpression is involved in the progression of ovarian cancer in a subset of the patients. Our results encourage the further evaluation of the prognostic and predictive values of Top IIalpha expression in ovarian carcinoma, which might help to assess the patients' risk profile, and the planning of an individualized therapy.

Immunohistochemical expression of BCRP and ERCC1 in biopsy specimen predicts survival in advanced non-small-cell lung cancer treated with cisplatin-based chemotherapy

PURPOSE

The aim of this study was to determine the prognostic value of expression of ATP binding cassette (ABC) transporter proteins and DNA repair gene proteins by immunohistochemically staining tumor biopsy specimens from patients with advanced non-small-cell lung cancer (NSCLC) being treated with platinum-based chemotherapy.

EXPERIMENTAL DESIGN

Expression of ABC transporter proteins, including BCRP (breast cancer resistance protein) and MRP2 (multidrug resistance proteins 2), and the DNA-repair-related proteins, ERCC1 (excision repair cross-complementation group 1) and BRCA1 (breast cancer type 1 susceptibility protein) was assessed immunohistochemically in 156 tumor samples from untreated stage IV NSCLC patients. All of the patients had received platinum-based chemotherapy. Response to chemotherapy, progression-free survival (PFS), and overall survival were compared in relation to expression of each of the proteins and to clinicopathological factors.

RESULTS

High ERCC1 expression was associated with short survival (237 days vs. 453 days, log-rank P = 0.03), but not with response to chemotherapy or PFS. And high BCRP expression was associated with short survival (214 days vs. 412 days, log-rank P = 0.02) but not with response to chemotherapy or PFS. Multivariate analysis confirmed that negativity for the expression of BCRP tends to be an independent variable related to overall survival (P = 0.06).

CONCLUSIONS

This study examined ERCC1 and BCRP expression in biopsy specimens as candidates for predictors of the survival of patients with advanced NSCLC treated with platinum-based chemotherapy.

Expression of multidrug-resistance-related proteins P-glycoprotein, glutathione-S-transferases, topoisomerase-II and lung resistance protein in primary gastric cardiac adenocarcinoma

AIM

Multidrug resistance (MDR) is closely correlated to an unfavorable prognosis in various human cancers. However, the clinical significance of the expression of MDR-related proteins p-glycoprotein (PGP), glutathione-s-transferases (GST-pi), topoisomerase-II (Topo-II) and lung resistance protein (LRP) in primary gastric cardiac adenocarcinoma (PGCA) remains unclear. In this present study, the total of the four kinds of MDR-related proteins mentioned above were detected by using immunohistochemistry, and their clinical significance in chemoresistance were also investigated.

METHODS

This retrospective study included 69 resected specimens from patients with PGCA. The expression of PGP, GST-pi, Topo-II and LRP in formalin-fixed paraffin-embedded tissue sections was determined by a labelled streptavidin-biotin immunohistochemical technique, and the results were analyzed in correlation with clinicopathological data. None of these patients received chemotherapy prior to surgery.

RESULTS

The positive rates of expression of PGP, GST-pi, Topo-II and LRP in malignant tissues (49.2%, 75.4%, 68.1% and 58%, respectively) were all higher than that of the normal tissues(0, 30%, 20% and 0, respectively, P < 0.01). PGP expression in tumors that had metastasized was significantly more frequent than in tumors that had not metastasized (67.5% vs 24.1%, P < 0.01). The expression of PGP was closely related with clinicopathologic staging (staging 1/2 vs 3/4, 28.6% vs 58.3%, P < 0.05). No significant correlation was shown between PGP and increasing differentiated degree (40%, 42.4% and 61.5%, P > 0.05). GST-pi expression status progressively increased with increasing differentiated degree (40%, 75.8% and 88.5%, P < 0.05) and clinicopathologic stage (staging 1/2 vs 3/4, 57.1% vs 83.3%, P < 0.05). In addition, a significant positive correlation was also observed between GST-pi and lymphatic metastasis (with vs. without metastasis, 87.5% vs 58.6%, P < 0.05). The expression of Topo-II was associated with increasing differentiated degree (33.3%, 69.7 and 80.7%, P < 0.01). No significant differences with Topo-II expression were found in relation to the clinicopathologic stage (staging 1/2 vs 3/4, 57.1% vs 72.9%, P > 0.05) and lymphatic metastasis (with vs. without metastasis, 65.0% vs 72.4%, P > 0.05). Moreover, a significant difference with the expression of LRP was found in relation to the clinicopathologic stage (staging 1/2 vs 3/4, 38% vs 66.6%, P < 0.05), and lymphatic metastasis (with vs without metastasis, 70.0% vs 41.4%, P < 0.05). Comparing the well, moderately and poorly differentiated cohort, a non-statistical increasing trend towards LRP expression status was noted (50.0%, 54.5% and 65.3%, respectively, P > 0.05). Besides, the co-expression of all four tested MDR-related proteins also existed. The positive rates of co-expression of PGP and GST-pi, PGP and Topo-II, PGP and LRP, GST-pi and Topo-II, LRP and GST-pi, LRP and Topo-II, PGP, GST-pi, Topo-II and LRP in malignant cells were 23.2%, 15.9%, 11.6%, 13.0, 26.1, 7.24, 5.8, respectively.

CONCLUSIONS

MDR-related proteins PGP, GST-pi, Topo-II alpha and LRP are involved in multiple mechanisms of drug resistance in PGCA. Combined determination of PGP, GST-pi, Topo-II and LRP may be prospectively valuable for optimizing the chemotherapy regimes, developing high quality anti-cancer drugs, and further predicting the outcomes of those patients with PGCA.

Topoisomerase IIalpha expression as an independent prognostic factor in Hodgkin's lymphoma

PURPOSE

To correlate the immunohistochemical expression of topoisomerase IIalpha (topoIIalpha) in Hodgkin's lymphoma (HL) with clinicopathological parameters, the expression of Ki-67 and the outcome of patients, who had been homogenously treated with ABVD or equivalent regimens.

EXPERIMENTAL DESIGN

Immunohistochemistry using the monoclonal antibody Ki-S1 (topoIIalpha) was performed in 238 HL patients. MiB1 (Ki-67) expression was evaluated in 211/238.

RESULTS

The mean +/- SD percentage of topoIIalpha- and Ki-67-positive Hodgkin-Reed-Sternberg (HRS) cells was 63 +/- 19% (5%-98%) and 73 +/- 19% (8%-99%), respectively. The median percentage of topoIIalpha-positive HRS cells was 64% (interquartile range, 51-78%). There was no correlation between topoIIalpha expression and patient characteristics. TopoIIalpha and Ki-67 expression were correlated (Spearman's Rho 0.255, P < 0.001). TopoIlalpha expression within the highest quartile of this patient population was predictive of failure free survival (FFS) (10-year rates 82 +/- 3% vs 68 +/- 7%, P = 0.02 for patients falling into the quartiles 1-3 and 4 respectively). In multivariate analysis topoIIalpha expression was independently predictive of FFS.

CONCLUSION

TopoIIalpha was expressed in all cases of HL showing a correlation with Ki-67 expression. Under current standard therapy including drugs inhibiting its activity, topoIIalpha was an independent adverse predictor of FFS with no statistically significant correlation with other established prognostic factors.

Resistance to chemotherapy in cancer: a complex and integrated cellular response

Inherent and acquired resistance pathways account for the high rate of failure in cancer chemotherapy. The mechanisms or pathways mediating resistance may be classified as pharmacokinetic (i.e. alter intratumour drug exposue) or pharmacodynamic (i.e. failure to elicit cytotoxicity). More often than not, the resistant phenotype is characterised by alterations in multiple pathways. Consequently, the pathways may act synergistically or generate a broad spectrum of resistance to anticancer drugs. There has been a great deal of systematic characterisation of drug resistance in vitro. However, translating this greater understanding into clinical efficacy has rarely been achieved. This review explores the phenomenon of drug resistance in cancer and highlights the gap between in vitro and in vivo observations. This gap presents a major obstacle in overcoming drug resistance and restoring sensitivity to chemotherapy.

Screening and detection of portal vein tumor thrombi-associated serum low molecular weight protein biomarkers in human hepatocellular carcinoma

PURPOSE

Serum low molecular weight protein biomarkers might be important in relation to portal vein tumor thrombi (PVTT) in hepatocellular carcinoma (HCC). This study aimed to screen and to detect these biomarkers.

METHODS

We selected sera of 3 groups from 12 healthy volunteers, 12 HCC patients without PVTT and 12 HCC patients with PVTT, respectively. By using two-dimensional gel electrophoresis (2-DE) in which the first dimension was 16% SDS-PAGE, serum protein images of 3 groups were analyzed by Image Master Software. The differential protein spots were further identified by MALDI-TOF MS/MS.

RESULTS

Compared with 12.5% SDS-PAGE gel, there were more protein bands between 3 and 20 kDa in 16% SDS-PAGE gel and low molecular weight (MW) protein spots (< 20 kDa) were clearly shown. Fifteen differential protein spots representing five proteins were found in the three groups by inter-class comparison and were then identified. Compared with the healthy group, apolipoprotein A-I, lipoprotein CIII, transthyretin and DNA topoisomerase II were down regulated in HCC groups while haptoglobin-2 was over expressed. All the five proteins were less in PVTT group than in non-PVTT group.

CONCLUSION

The expression of low MW serum protein changes obviously in the beginning and progressive stage of HCC, and differentially expressed low MW proteins might be the potential biomarkers in early prognostication and surveillance of treatment for HCC and PVTT.

Multidrug resistance proteins do not predict benefit of adjuvant chemotherapy in patients with completely resected non-small cell lung cancer: International Adjuvant Lung Cancer Trial Biologic Program

PURPOSE

The purpose of our study was to determine whether multidrug resistance proteins (MRP) are of prognostic and/or predictive value in patients who were enrolled into the International Adjuvant Lung Cancer Trial (IALT).

EXPERIMENTAL DESIGN

Expression of MRP1 and MRP2 was immunohistochemically assessed in tumor specimens obtained from 782 IALT patients. Prognostic and predictive analyses were based on Cox models adjusted for clinical and pathologic variables.

RESULTS

MRP1 expression was considered positive in 364 (47%) patients and MRP2 expression in 313 (40%) patients. MRP2-positive patients had a significantly shorter overall survival than MRP2-negative patients in the total patient population [adjusted hazard ratio for death, 1.37; 95% confidence interval (95% CI), 1.09-1.72; P = 0.007]. There was no significant association between MRP1 expression and overall survival. Neither MRP1 nor MRP2 predicted response to adjuvant cisplatin-based chemotherapy.

CONCLUSIONS

MRP2 expression is an independent prognostic factor in patients with completely resected non-small cell lung cancer but neither MRP1 nor MRP2 was of predictive value in patients enrolled into the IALT.

Recommendations For Clinical Use Of Tumor Markers In Lung Cancer

Kancer pluća predstavlja jedan od najozbiljnijih problema moderne onkologije. Uprkos kontinuiranom napretku u dijagnostičkim metodama, kod 50-70% pacijenata s kancerom pluća, bolest se dijagnostikuje u uznapredovalom stadijumu, isključujuci na taj način mogućnost radikalne terapije. Određivanje tumorskih markera kod kancera pluća može biti od pomoći u postavljanju dijagnoze, praćenju pacijenta i terapije, a takođe može da pruži dodatne informacije u prognostičke svrhe. U daljem tekstu opisani su odgovarajući serumski markeri kod dve glavne forme tumora pluća-mikrocelularnog i nemikrocelularnog (SCLC i NSCLC), kao i abnormalne supstance identifikovane u tumorima pluća ili njihovim metastazama, kao što su molekularni markeri, markeri prognoze u primeni neoadjuvantne ili adjuvantne terapije i mikrometastazama koštane srži ili limfnom čvoru.

[Expression of multidrug resistance (MDR)-associated proteins in solid tumors]

The causes of drug resistance in tumor cells vary widely. The present study aims to provide an update of multidrug resistance in tumor cells and, in particular, of multidrug resistance-associated proteins.

Quantitative analysis of topoisomerase IIα to rapidly evaluate cell proliferation in brain tumors

Immunohistochemical cell proliferation analyses have come into wide use for evaluation of tumor malignancy. Topoisomerase IIalpha (topo IIalpha), an essential nuclear enzyme, has been known to have cell cycle coupled expression. We here show the usefulness of quantitative analysis of topo IIalpha mRNA to rapidly evaluate cell proliferation in brain tumors. A protocol to quantify topo IIalpha mRNA was developed with a real-time RT-PCR. It took only 3 h to quantify from a specimen. A total of 28 brain tumors were analyzed, and the level of topo IIalpha mRNA was significantly correlated with its immuno-staining index (p<0.0001, r=0.9077). Furthermore, it sharply detected that topo IIalpha mRNA decreased in growth-inhibited glioma cell. These results support that topo IIalpha mRNA may be a good and rapid indicator to evaluate cell proliferate potential in brain tumors.

Phase II Trial of Karenitecin in Patients with Malignant Melanoma: Clinical and Translational Study

PURPOSE

A phase II trial of the novel camptothecin karenitecin (BNP1350) was conducted to determine its efficacy and tolerability in patients with metastatic melanoma. Patients were biopsied to determine topoisomerase expression at baseline and response to therapy.

PATIENTS AND METHODS

Eligible patients had metastatic melanoma with up to three prior chemotherapy and/or any number of immunotherapy regimens. Treatment consisted of an i.v. infusion of 1 mg/m(2) karenitecin daily for 5 days with cycles repeated every 3 weeks. Fine-needle aspiration biopsies were done before treatment and on day 3 to determine topoisomerase expression from patients' tumors.

RESULTS

Forty-three patients were evaluable for response and toxicity. Most patients (72%) had stage M1C disease and were previously exposed to chemotherapy (56%). The investigational agent was well tolerated with limited gastrointestinal side effects or fatigue. The major toxicity seen was reversible noncumulative myelosuppression. One patient had a complete response after 11 months of therapy. No partial responses were seen, but 33% of the patients had disease stabilization lasting > or =3 months. Topoisomerase I, IIalpha, and IIbeta expression and localization were determined in a subset of patients. Topoisomerase I expression was highest, followed by topoisomerase IIbeta and topoisomerase IIalpha.

CONCLUSION

Karenitecin was a well-tolerated investigational agent in this phase II study; side effects were generally mild and mostly hematologic. Karenitecin has significant activity in metastatic melanoma. Melanoma metastases express high levels of topoisomerase I. We did not observe any compensatory increase in topoisomerase II upon treatment with karenitecin.

Ki-67 expression and patients survival in lung cancer: systematic review of the literature with meta-analysis

Among new biological markers that could become useful prognostic factors for lung carcinoma, Ki-67 is a nuclear protein involved in cell proliferation regulation. Some studies have suggested an association between Ki-67 and poor survival in lung cancer patients. In order to clarify this point, we have performed a systematic review of the literature, using the methodology already described by our Group, the European Lung Cancer Working Party. In total, 37 studies, including 3983 patients, were found to be eligible. In total, 49% of the patients were considered as having a tumour positive for the expression of Ki-67 according to the authors cutoff. In all, 29 of the studies dealt with non-small-cell lung carcinoma (NSCLC), one with small-cell carcinoma (SCLC), two with carcinoid tumours and five with any histology. In terms of survival results, Ki-67 was a bad prognosis factor for survival in 15 studies while it was not in 22. As there was no statistical difference in quality scores between the significant and nonsignificant studies evaluable for the meta-analysis, we were allowed to aggregate the survival results. The combined hazard ratio for NSCLC, calculated using a random-effects model was 1.56 (95% CI: 1.30–1.87), showing a worse survival when Ki-67 expression is increased. In conclusion, our meta-analysis shows that the expression of Ki-67 is a factor of poor prognosis for survival in NSCLC.

Breast cancer resistance protein impacts clinical outcome in platinum-based chemotherapy for advanced non-small cell lung cancer

PURPOSE

The purpose of this study was to investigate the relationship between the level of expression of ATP-binding cassette (ABC) transporter proteins, and response to chemotherapy and prognosis in advanced non-small cell lung cancer (NSCLC).

EXPERIMENTAL DESIGN

Expression of ABC transporter proteins, including P-glycoprotein, multidrug resistance protein (MRP) 1, MRP2, MRP3, and breast cancer resistance protein (BCRP), was examined immunohistochemically in 72 formalin-fixed tumor samples from untreated stage IIIB or IV NSCLC patients. All of the patients received platinum-based chemotherapy. Response to chemotherapy, progression-free survival (PFS), and overall survival were compared in relation to expression of each of the ABC transporter proteins and clinicopathological factors.

RESULTS

Expression of P-glycoprotein, MRP1, and MRP3 was not significantly associated with response to chemotherapy or survival. MRP2 expression was associated with overall survival (P = 0.002) but not with response to chemotherapy and PFS. By contrast, the response rate to chemotherapy of patients with BCRP-negative tumors was 44%, as opposed to 24% in patients with BCRP-positive tumors. Response rate was lower in BCRP-positive tumors, although this difference was not statistically significant (P = 0.08). BCRP-positive patients had also shorter PFS (P = 0.0003) and overall survival (P = 0.004) than BCRP-negative patients. Multivariate analysis confirmed BCRP status as an independent variable related to PFS (P = 0.001).

CONCLUSIONS

Positive immunostaining for BCRP appears to be a predictor of survival in patients with advanced NSCLC. These findings indicate that BCRP may serve as a molecular target for reducing drug resistance to chemotherapy in advanced NSCLC patients.

The antitumor triazoloacridone C-1305 is a topoisomerase II poison with unusual properties

C-1305 [S-[[3-(dimethylamino)propyl]amino]-8-hydroxy-6H-v-triazolo[4,5,1-de]acridin-6-one] is a triazoloacridone with excellent activity in colon cancer models. The mechanism of C-1305 is unknown, although similarities in the chemical structure between C-1305 and amsacrine suggest common cellular targets. Here, we report that C-1305 is a topoisomerase II poison that is able to induce cleavable complexes with topoisomerase II in vitro as well as in living cells. Even at optimal concentrations, C-1305 is a much weaker inducer of cleavable complexes than amsacrine. Because the cytotoxic activities of the two compounds after continuous drug exposure are comparable, these findings suggest that the low levels of cleavable complexes induced by C-1305 may be unusually toxic. In contrast to amsacrine, the cytotoxicity of C-1305 is strongly time-dependent, with at least 24 h of drug exposure required for optimal cytotoxicity. The p53 tumor suppressor is inactivated in the majority of human tumors, including colorectal cancers. We therefore compared the long-term cytotoxic effects of C-1305, amsacrine, and doxorubicin on human cell lines in which the p53 or p21 pathways have been specifically disrupted by targeted homologous recombination. Disruption of p53 and p21 had minor influence on the cytotoxicity of doxorubicin, whereas p53 but not p21 disruption was associated with increased resistance to amsacrine. In marked contrast, disruption of p53 and p21 was associated with increased sensitivity to C-1305. Taken together, our results show that exposure to C-1305 is accompanied by the formation of low levels of potent cleavable complexes that are selectively toxic toward tumor cells with defective p53 function.

To predict response chemotherapy using technetium-99m tetrofosmin chest images in patients with untreated small cell lung cancer and compare with p-glycoprotein, multidrug resistance related protein-1, and lung resistance-related protein expression

Our preliminary studies found technetium-99m tetrofosmin (Tc- TF) chest imaging was related to Pgp or MRP1 expression and successfully predict chemotherapy response and in SCLC in human. However, there was no published literature to study relationship of Tc-TF chest images and LRP expression in SCLC patients. Therefore, the aim of this study was to investigate the relationships among Tc- TF accumulation in untreated small cell lung cancer (SCLC), the expression of P-glycoprotein (Pgp), multidrug resistance related protein-1 (MRP1), and lung resistance-related protein (LRP), as well as the response to chemotherapy in patients with untreated SCLC. Thirty patients with SCLC were studied with chest images 15 to 30 minutes after intravenous injection of Tc-TF before chemotherapeutic induction. Tumor-to-background (T/B) ratios were obtained on the static and plantar Tc-TF chest images. The response to chemotherapy was evaluated upon completion of chemotherapy by clinical and radiological methods. These patients were separated into 15 patients with good response and 15 patients with poor response. No significant differences of prognostic factors (Karnofsky performance status, tumor size, or tumor stage) were found between the patients with good and poor responses. Immunohistochemical analyses were performed on multiple nonconsecutive sections of biopsy specimens to detect Pgp, MRP1, and LRP expression. The difference in T/B ratios on the Tc-TF chest images of the patients with good versus poor response was significant. The differences in T/B ratios of the patients with positive versus negative Pgp expression and with positive versus negative MRP1 expression were significant. The difference in T/B ratios of the patients with positive versus negative LRP expression was not significant. We concluded that Tc-TF chest images could accurately predict chemotherapy response of patients with SCLC. In addition, The Tc-TF tumor uptake was related to Pgp or MRP1 but not LPR expression in SCLC.

Predictive value of expression of P53, Bcl-2 and lung resistance-related protein for response to chemotherapy in non-small cell lung cancers

Chemoresistance is a major problem in the chemotherapy of non-small cell lung cancers (NSCLCs). Several mechanisms are thought to be involved in drug resistance, including those associated with apoptosis, drug transport and detoxification. Here, we investigated the predictive value of P53, Bcl-2 and lung resistance-related protein (LRP) expression for response to platinum-based chemotherapy, using transbronchial biopsy (TBB) specimens from patients with NSCLC. We evaluated TBB specimens from 57 patients with NSCLC who had not previously been treated with either chemotherapy or radiotherapy before TBB, and who were treated with systemic platinum-based chemotherapy. The specimens included 33 adenocarcinomas, 22 squamous cell carcinomas and two large cell carcinomas. One to 6 courses of chemotherapy were administered. Expression of P53, Bcl-2 and LRP was analyzed by immunohistochemistry using TBB specimens. Positive expression of P53, Bcl-2 and LRP was observed in 28 (49%), 41 (71%) and 42 (73%) of the 57 NSCLCs, respectively. P53 expression correlated significantly with response to chemotherapy in nonsquamous cell carcinomas, including adenocarcinomas and large cell carcinomas (response rates, 38% and 6% for patients with P53-positive and P53-negative tumors, respectively, P = 0.03). LRP expression significantly correlated inversely with response to chemotherapy in squamous cell carcinomas (response rates, 33% and 100% for patients with LRP-positive and LRP-negative tumors, respectively, P = 0.02). Bcl-2 expression did not correlate with response to chemotherapy. These findings indicate that immunostaining for P53 and LRP using TBB specimens may be useful for dividing patients with NSCLC into chemoresponsive and chemoresistant groups.

Pharmacogenetics of anticancer drug sensitivity in non-small cell lung cancer

In mammalian cells, the process of malignant transformation is characterized by the loss or down-regulation of tumor-suppressor genes and/or the mutation or overexpression of proto-oncogenes, whose products promote dysregulated proliferation of cells and extend their life span. Deregulation in intracellular transduction pathways generates mitogenic signals that promote abnormal cell growth and the acquisition of an undifferentiated phenotype. Genetic abnormalities in cancer have been widely studied to identify those factors predictive of tumor progression, survival, and response to chemotherapeutic agents. Pharmacogenetics has been founded as a science to examine the genetic basis of interindividual variation in drug metabolism, drug targets, and transporters, which result in differences in the efficacy and safety of many therapeutic agents. The traditional pharmacogenetic approach relies on studying sequence variations in candidate genes suspected of affecting drug response. However, these studies have yielded contradictory results because of the small number of molecular determinants of drug response examined, and in several cases this approach was revealed to be reductionistic. This limitation is now being overcome by the use of novel techniques, i.e., high-density DNA and protein arrays, which allow genome- and proteome-wide tumor profiling. Pharmacogenomics represents the natural evolution of pharmacogenetics since it addresses, on a genome-wide basis, the effect of the sum of genetic variants on drug responses of individuals. Development of pharmacogenomics as a new field has accelerated the progress in drug discovery by the identification of novel therapeutic targets by expression profiling at the genomic or proteomic levels. In addition to this, pharmacogenetics and pharmacogenomics provide an important opportunity to select patients who may benefit from the administration of specific agents that best match the genetic profile of the disease, thus allowing maximum activity.