Anupama Sharma

Gene expression-based survival prediction in lung adenocarcinoma: A multi-site, blinded validation study

Although prognostic gene expression signatures for survival in early-stage lung cancer have been proposed, for clinical application, it is critical to establish their performance across different subject populations and in different laboratories. Here we report a large, training–testing, multi-site, blinded validation study to characterize the performance of several prognostic models based on gene expression for 442 lung adenocarcinomas. The hypotheses proposed examined whether microarray measurements of gene expression either alone or combined with basic clinical covariates (stage, age, sex) could be used to predict overall survival in lung cancer subjects. Several models examined produced risk scores that substantially correlated with actual subject outcome. Most methods performed better with clinical data, supporting the combined use of clinical and molecular information when building prognostic models for early-stage lung cancer. This study also provides the largest available set of microarray data with extensive pathological and clinical annotation for lung adenocarcinomas.

RRM1 modulated in vitro and in vivo efficacy of gemcitabine and platinum in non-small-cell lung cancer.

PURPOSE RRM1 encodes the regulatory subunit of ribonucleotide reductase and is a molecular target of gemcitabine. Previous studies showed increased RRM1 expression on continuous exposure of cell lines to gemcitabine and suggested improved survival for patients with low as opposed to high tumoral RRM1 expression when treated with gemcitabine-containing chemotherapy. However, the principal hypothesis that intratumoral levels of gene expression are associated with disease response has not been addressed. PATIENTS AND METHODS We constructed genetically modified lung cancer cell lines with increased and decreased RRM1 expression to investigate the in vitro 50% inhibitory concentration (IC50) for gemcitabine, cisplatin, and carboplatin. A prospective phase II clinical trial in patients with locally advanced non-small-cell lung cancer was conducted with pretreatment tumor collection for determination of RRM1 and ERCC1 expression by real-time reverse transcriptase polymerase chain reaction. The levels of gene expression were correlated with tumor response after two cycles of gemcitabine and carboplatin. RESULTS In cell lines with a genetically engineered 15-fold RRM1 expression range, the gemcitabine IC50 had a 100-fold range, and the cisplatin and carboplatin IC50 had a two-fold range. They were highest in constructs with high RRM1 expression. In the prospective clinical trial, RRM1 expression was significantly (P = .002) and inversely correlated (r = -0.498) with disease response. ERCC1 expression showed a similar trend (P = .099). CONCLUSION The results strongly suggest that tumoral RRM1 expression is a major predictor of disease response to gemcitabine/platinum chemotherapy. ERCC1 expression is predictive of response albeit to a lesser degree.

Feasibility and Efficacy of Molecular Analysis-Directed Individualized Therapy in Advanced Non–Small-Cell Lung Cancer

PURPOSE The treatment of patients with advanced non-small-cell lung cancer (NSCLC) is based on clinical trials experience. Molecular characteristics that impact metabolism and efficacy of chemotherapeutic agents are not used for decision making. Ribonucleotide reductase subunit 1 (RRM1) is crucial for nucleotide metabolism, and it is the dominant molecular determinant of gemcitabine efficacy. Excision repair cross-complementing group 1 gene (ERCC1), a component of the nucleotide excision repair complex, is important for platinum-induced DNA adduct repair. We hypothesized that selection of double-agent chemotherapy based on tumoral RRM1 and ERCC1 expression would be feasible and beneficial for patients with advanced NSCLC. PATIENTS AND METHODS We conducted a prospective phase II clinical trial in patients with advanced NSCLC. Patients were required to have a dedicated tumor biopsy for determination of RRM1 and ERCC1 gene expression by real-time quantitative reverse transcriptase polymerase chain reaction. Double-agent chemotherapy consisting of carboplatin, gemcitabine, docetaxel, and vinorelbine was selected based on gene expression. Disease response and patient survival were monitored. RESULTS Eighty-five patients were registered, 75 had the required biopsy without significant complications, 60 fulfilled all eligibility criteria, and gene expression analysis was not feasible in five patients. RRM1 expression ranged from 0 to 1,637, ERCC1 expression ranged from 1 to 8,103, and their expression was correlated (Spearmans rho = 0.46; P < .01). Disease response was 44%. Overall survival was 59% and progression-free survival was 14% at 12 months, with a median of 13.3 and 6.6 months, respectively. CONCLUSION Therapeutic decision making based on RRM1 and ERCC1 gene expression for patients with advanced NSCLC is feasible and promising for improvement in patient outcome

RRM1 and PTEN as prognostic parameters for overall and disease-free survival in patients with non-small-cell lung cancer

PURPOSE RRM1 has important functions in the determination of the malignant phenotype. It controls cell proliferation through deoxynucleotide production and metastatic propensity through PTEN induction. It is located in a region of loss of heterozygosity in non-small-cell lung cancer (NSCLC), which is a predictor of poor survival. We hypothesized that RRM1 expression would be a significant predictor of outcome in NSCLC. PATIENTS AND METHODS A retrospective data set of 49 patients and a prospective data set of 77 patients with resectable NSCLC were studied. RNA was extracted from tumor and normal lung tissue, and expression of the genes RRM1, PTEN, and RRM2 was determined by real-time quantitative polymerase chain reaction. RESULTS RRM1 expression was significantly correlated with PTEN and RRM2 expression in tumor tissue. RRM1 and PTEN expression in tumor tissue was highly predictive of overall (P =.011 and.018, respectively) and disease-free survival (P =.002 and.026, respectively). Patients with high levels of expression lived longer and had disease recurrence later than patients with low levels of RRM1 and PTEN. In a multivariate analysis, high RRM1 expression was predictive of long survival independent of tumor stage, performance status, and weight loss. CONCLUSION RRM1 is a biologically and clinically important determinant of malignant behavior in NSCLC. Knowing the level of expression of this gene adds significant information to management decisions independent of the currently used outcome predictors of tumor stage, performance status, and weight loss. Future clinical trials should stratify patients based on expression of this gene to avoid unwanted biases.

Clinical Efficacy and Predictive Molecular Markers of Neoadjuvant Gemcitabine and Pemetrexed in Resectable Non-Small-Cell Lung Cancer

Background: A trial of neoadjuvant gemcitabine and pemetrexed (GP) chemotherapy in patients with resectable non-small cell lung cancer was conducted. The goal was to achieve a disease response rate of 50% and to determine if the expression levels of genes associated with GP metabolism are predictive of response. Methods: Patients had staging with a computed tomography scan, whole body F-18 fluorodeoxyglucose positron emission tomography, and mediastinoscopy. Four biweekly cycles of GP were given. Patients were restaged, and those with resectable stage IB-III disease had thoracotomy. Fresh frozen tumor specimens were collected before and after chemotherapy and the mRNA levels of 14 target genes determined by real-time reverse transcription polymerase chain reaction. Results: Fifty-two patients started therapy. The radiographic disease response rate was 35% (95% confidence interval 21.7-49.6%), and the progression rate was 6%. Forty-six patients had a thoracotomy. The complete tumor resection rate was 77% (40/52). There were no perioperative deaths or deaths related to chemotherapy. Tumor response to chemotherapy was inversely correlated with the level of expression of RRM1 (p < 0.001; regulatory subunit of ribonucleotide reductase) and TS (p = 0.006; thymidylate synthase); i.e., the reduction in tumor size was greater in those with low levels of expression. Conclusions: Neoadjuvant GP is well tolerated and produces an objective response rate of 35%. Tumoral RRM1 and TS mRNA levels are predictive of disease response and should be considered as parameters for treatment selection in future trials with this regimen.

Phase II study of neoadjuvant chemotherapy with gemicitabine and pemetrexed (NeoGP) in resectable non-small-cell lung cancer (NSCLC): MCC 13726

7314 Objective: We are assessing the efficacy of a non-platinum-containing doublet chemotherapy consisting of gemcitabine and pemetrexed as induction therapy (NeoGP) prior to surgical resection in ...

Predictive utility of RRM1 promoter polymorphisms on outcome of patients with non-small cell lung cancer

7155 Background: RRM1 is a gene crucial for determination of the tumor phenotype. It encodes the regulatory subunit of ribonucleotide reductase, and it is a molecular target of gemcitabine. In addition, RRM1 induces PTEN expression and inhibits cell migration, invasion, and metastasis formation. In patients with resected lung cancers, increased levels of RRM1 are highly associated with long survival. In contrast, patients on gemcitabine and cisplatin therapy for advanced disease have a poor survival if RRM1 expression is high presumably because of decreased efficacy of chemotherapy. METHODS We analyzed the RRM1 promoter for polymorphisms in an effort to develop a practical and inexpensive assay for RRM1 expression. RESULTS Two single nucleotide polymorphisms, RR37 and RR524, were discovered. These polymorphisms impacted promoter activity in vitro. Promoter allelotypes were highly associated with overall (p=0.06) and disease-free (p=0.03) patient survival. The allelotype with the highest predicted activity was associated with the best patient outcome. However, we did not find an association between allelotype and tumoral RRM1 expression. This is likely a result of the limited impact of the described promoter polymorphisms on overall in vivo gene expression. CONCLUSIONS We conclude that clinical studies using RR37 and RR524 for decisions on chemotherapy are premature and that further functional studies on the RRM1 promoter are required to fully elucidate factors controlling RRM1 expression. No significant financial relationships to disclose.