Steve Rowley

Prognostic Utility of the 21-Gene Assay in Hormone Receptor–Positive Operable Breast Cancer Compared With Classical Clinicopathologic Features

PURPOSE Adjuvant! is a standardized validated decision aid that projects outcomes in operable breast cancer based on classical clinicopathologic features and therapy. Genomic classifiers offer the potential to more accurately identify individuals who benefit from chemotherapy than clinicopathologic features. PATIENTS AND METHODS A sample of 465 patients with hormone receptor (HR) -positive breast cancer with zero to three positive axillary nodes who did (n = 99) or did not have recurrence after chemohormonal therapy had tumor tissue evaluated using a 21-gene assay. Histologic grade and HR expression were evaluated locally and in a central laboratory. RESULTS Recurrence Score (RS) was a highly significant predictor of recurrence, including node-negative and node-positive disease (P < .001 for both) and when adjusted for other clinical variables. RS also predicted recurrence more accurately than clinical variables when integrated by an algorithm modeled after Adjuvant! that was adjusted to 5-year outcomes. The 5-year recurrence rate was only 5% or less for the estimated 46% of patients who have a low RS (< 18). CONCLUSION The 21-gene assay was a more accurate predictor of relapse than standard clinical features for individual patients with HR-positive operable breast cancer treated with chemohormonal therapy and provides information that is complementary to features typically used in anatomic staging, such as tumor size and lymph node involvement. The 21-gene assay may be used to select low-risk patients for abbreviated chemotherapy regimens similar to those used in our study or high-risk patients for more aggressive regimens or clinical trials evaluating novel treatments.

Relationship between Topoisomerase 2A RNA Expression and Recurrence after Adjuvant Chemotherapy for Breast Cancer

Purpose: To perform an exploratory analysis of the relationship between gene expression and recurrence in operable hormone receptor (HR)–positive, human epidermal growth factor receptor 2 (HER2)–normal breast cancer patients treated with adjuvant doxorubicin-containing chemotherapy. Experimental Design: RNA was extracted from archived tumor samples derived from 378 patients with stage I to III HR-positive, HER2-normal breast cancer and analyzed by reverse transcription-PCR for a panel of 374 genes, including the 21-gene recurrence score (RS). Patients were randomized to receive adjuvant doxorubicin plus cyclophosphamide or docetaxel in trial E2197, with no difference in recurrence seen in the treatment arms. All available recurrent cases were selected plus a nonrecurrent cohort. Cox proportional hazard models were used to identify relationships between gene expression and recurrence. Results: TOP2A expression exhibited the strongest association with increased recurrence risk (P = 0.01), and was significantly associated with recurrence (P = 0.008) in a multivariate analysis adjusted for clinicopathologic features. Elevated TOP2A expression above the median was associated with a 2.6-fold increase (95% confidence interval, 1.3-5.2; P = 0.008) in risk of recurrence if the RS was <18, and a 2.0-fold increase (95% confidence interval, 1.2-3.2, P = 0.003) if there was an intermediate RS of 18 to 30. Conclusions: In patients with HR-positive, HER2-normal breast cancer, a population known to have a low incidence of TOP2A gene alterations thought to be predictive of anthracycline benefit, there is a range of TOP2A RNA expression that is strongly associated with recurrence after adjuvant anthracyclines, which provides information complementary to RS, indicating that it merits further evaluation as a prognostic and predictive marker. (Clin Cancer Res 2009;15(24):7693–700)

Relationship between Quantitative GRB7 RNA Expression and Recurrence after Adjuvant Anthracycline Chemotherapy in Triple-Negative Breast Cancer

Purpose: To conduct an exploratory analysis of the relationship between gene expression and recurrence in patients with operable triple-negative breast cancer (TNBC) treated with adjuvant doxorubicin-containing chemotherapy. Experimental Design: RNA was extracted from archived tumor samples derived from 246 patients with stage I-III TNBC treated with adjuvant doxorubicin-containing chemotherapy, and was analyzed by quantitative reverse transcriptase PCR for a panel of 374 genes. The relationship between gene expression and recurrence was evaluated using weighted Cox proportional hazards model score tests. Results: Growth factor receptor bound protein 7 (GRB7) was the only gene for which higher expression was significantly associated with increased recurrence in TNBC (Korns adjusted P value = 0.04). In a Cox proportional hazards model adjusted for clinicopathologic features, higher GRB7 expression was associated with an increased recurrence risk (HR = 2.31; P = 0.04 using the median as the split). The 5-year recurrence rates were 10.5% [95% confidence intervals (CI), 7.8–14.1] in the low and 20.4% (95% CI, 16.5–25.0) in the high GRB7 groups. External validation in other datasets indicated that GRB7 expression was not prognostic in two adjuvant trials including variable systemic therapy, but in two other trials showed that high GBR7 expression was associated with resistance to neoadjuvant doxorubicin and taxane therapy. Conclusions: GRB7 was associated with an increased risk of recurrence in TNBC, suggesting that GRB7 or GRB7-dependent pathways may serve as potential biomarkers for therapeutic targets. Therapeutic targeting of one or more factors identified which function as interaction nodes or effectors should also be considered. Clin Cancer Res; 17(22); 7194–203. ©2011 AACR.

Gene Expression Profiling of Phenotypically-Defined Hormone-Receptor Positive Breast Cancer: Evidence for Increased Transcriptional Activity of the Insulin Growth Factor Receptor Pathway and Other Pathways.

Background: Approximately 70% of all breast cancers are hormone receptor (HR)-positive tumors that are sensitive to endocrine therapy, but some patients have recurrence despite adjuvant endocrine therapy. We performed an exploratory analysis of gene expression in HR-pos operable breast cancer in order to identify potential novel therapeutic targets and biomarkers associated with recurrence. Methods: RNA was extracted from primary tumor samples obtained from 776 patients with stage I-III breast cancer treated with adjuvant chemohormonal therapy in trial E2197 (JCO 2008; 26: 4092-4099), of whom 458 had HR-pos disease (defined in a central lab; JCO 2008; 26: 2473). We evaluated RNA expression patterns (by quantitative RT-PCR using a panel of 371 rationally selected genes) in HR-pos cases compared with the HR-neg cases using weighted T statistics, and determined which genes in the HR-pos, HER2-neg group were associated with recurrence (using Cox proportional hazards model score test, Korn9s adjusted P value Results: The top 10 genes exhibiting significantly higher expression in the HR-pos group (p≤ 6.17e-160) included ESR1 plus 5 estrogen regulated genes, confirming our approach of evaluating gene expression in phenotypically-defined subsets. Other pathways that exhibited higher expression in the HR-pos group (among the 40 top genes with higher expression, p IRS1, IGFR1, IGFB2 ), Ras ( RhoB, RhoC, RAB27B, GGPS1 ), and HER pathways ( ERBB2, ERBB3, ERBB4 ), and other genes involved in apoptosis ( BCL2, BCL2L1, BAG1, NME6, BBC3 ), signaling ( MAPK3, SEMA3F, RXRA ), mismatch repair ( MSH3 ), cell cycle regulation ( CCND1 ), stress response ( HSPB1 ), and tumor suppressor genes ( TP53BP1, APC ). These patterns were similar in HER2-pos cases. Pathway analysis (Ingenuity) revealed substantial interconnectivity among these genes, especially between IGFR1 , ERB2/3/4 , MAPK3 , BCL2 , and CCND1 , but not RhoB/RhoC . Genes for which increased expression was associated with increased recurrence included those associated with proliferation ( TOP2A, AURKB, PLK1 ) and apoptosis ( BIRC5 - survivin). Conclusions: This exploratory analysis reveals several pathways that exhibit higher transcriptional expression in HR-pos disease, some of which are also associated with a higher risk of recurrence, suggesting that they may be potential therapeutic targets. This provides rationale for testing agents currently available in the clinic that inhibit the IGF and other pathways. Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 5165.

Abstract 805: Disruption of the MDM2-p53 interaction synergizes with MEK inhibition to induce cell death and promote tumor regression in p53 wild-type, Ras or Raf-mutant tumor models

Proceedings: AACR Annual Meeting 2014; April 5-9, 2014; San Diego, CA Disruption of the interaction between p53 and MDM2 with small molecules, and subsequent reactivation of p53, is an attractive treatment strategy for p53 wild-type tumors that has shown striking pre-clinical activity in models exhibiting genomic amplification of the MDM2 gene. However, MDM2 amplified tumors represent only a small proportion of the p53 wild-type tumor population, and single agent regressions may be limited outside of the MDM2 amplified context. In order to increase the potential clinical benefit of MDM2-p53 protein-protein interaction (PPI) inhibitors beyond tumors exhibiting amplification of MDM2, we performed an enhancer library combination screen to identify optimal combination partners for MDM2-p53 PPI inhibitors in p53 wild-type, MDM2 non-amplified tumor cells. The MDM2-p53 PPI inhibitor SAR405838 and a related molecule were examined in combination with an enhancer library of 200 oncology drugs representing a broad molecular diversity of targets across a panel of twenty p53 wild-type cancer cell lines. Analysis results showed that MEK inhibitors were the most statistically significant synergistic combination partners in this screen, with synergy observed in cell lines harboring mutations that activated MAP kinase pathway signaling. These synergy results were validated in independent experiments using the ray design methodology, and extended to multiple K-ras, N-ras and B-raf mutant contexts in vitro. In K-ras, N-ras or B-raf mutant cell lines, the combination of SAR405838 with the MEK inhibitor pimasertib resulted in p53 pathway activation, inhibition of pERK levels, induction of the apoptotic mediators PUMA and BIM, induction of phosphatidyl serine exposure, and induction of caspase activity. In the Ras/Raf wild-type cell line MCF7, no synergy was observed. In cell line and patient-derived xenografts in vivo, the combination of SAR405838 and pimasertib resulted in greater anti-tumor activity than single agents and induced regression in K-ras, N-ras and B-raf mutant tumor models derived from different tissue types, including complete regressions in multiple models. These data indicate that MEK inhibitors synergize with MDM2-p53 PPI inhibitors in tumor models that exhibit activated MAP kinase pathway signaling and p53 wild-type status. Given the relative lack of overlapping clinically significant toxicities of MDM2-p53 PPI inhibitors and MEK inhibitors, such a combination merits further investigation for the treatment of K-ras, N-ras, or B-raf mutant, p53 wild-type tumors, representing a large patient population with significant unmet medical need. Citation Format: Isabelle Meaux, Jean-Paul Nicolas, Steve Rowley, Sukhvinder Sidhu, Francoise Herve, Laurent Dassencourt, Fanny Windenberger, Dimitri Gorge-Bernat, Pascal Pannier, Donald Bergstrom, Laurent Debussche, James Watters. Disruption of the MDM2-p53 interaction synergizes with MEK inhibition to induce cell death and promote tumor regression in p53 wild-type, Ras or Raf-mutant tumor models. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 805. doi:10.1158/1538-7445.AM2014-805