The matrix metalloproteinase matrilysin (MMP-7) is expressed in the tumor cells of a majority of mouse intestinal and human colonic adenomas. We showed previously that matrilysin is a target gene of ␤-cateninTcf, the transcription factor complex whose activity is thought to play a crucial role in the initiation of intestinal tumorigenesis. Here we report that overexpression of a stable mutant form of ␤-catenin alone was not sufficient to effect expression of luciferase from a matrilysin promoter-luciferase reporter plasmid. However, cotransfection of the reporter with an expression vector encoding the PEA3 Ets transcription factor, or its close relatives ER81 and ERM, increased luciferase expression and rendered the promoter responsive to ␤-catenin-LEF-1 as well as to the AP-1 protein c-Jun. Other Ets proteins could not substitute for the PEA3 subfamily. Luciferase activity was induced up to 250-fold when PEA3, c-Jun, ␤-catenin, and LEF-1 were coexpressed. This combination of transcription factors was also sufficient to induce expression of the endogenous matrilysin gene. Furthermore, all matrilysin-expressing benign intestinal tumors of the Min mouse expressed a member of the PEA3 subfamily, as did all human colon tumor cell lines examined. These data suggest that the expression of members of the PEA3 subfamily, in conjunction with the accumulation of ␤-catenin in these tumors, leads to coordinate upregulation of matrilysin gene transcription, contributing to gastrointestinal tumorigenesis.

Purpose To determine the safety and efficacy of gefitinib, an EGFR tyrosine kinase inhibitor, in combination with radiation for newly diagnosed glioblastoma (GBM) patients. Methods and Materials Between 3/21/2002 and 5/03/2004 RTOG 0211 enrolled 31 and 147 GBM patients in the phase I and II arms respectively. Treatment consisted of daily oral gefinitnib started at the time of conventional cranial radiotherapy (RT) and continued post RT for 18 months or until progression. Tissue microarrays from 68 cases were analyzed for EGFR expression. Results The maximum tolerated dose (MTD) of gefitinib was determined to be 500 mg in patients on non enzyme-inducing anticonvulsant drugs (non-EIAEDs). All patients in the phase II component were treated at a gefitinib dose of 500mg; patients receiving EIADSs could be escalated to 750mg. The most common side-effects of gefitinib in combination with radiation were dermatologic and gastrointestinal. Median survival was 11.5 months for patients treated per protocol. There was no overall survival benefit for patients treated with gefitinib + RT when compared to a historical cohort of patients treated with RT alone, matched by RTOG RPA class distribution. Younger age was significantly associated with better outcome. Per protocol stratification, EGFR expression was not found to be of prognostic value for gefitinib + RT treated patients. Conclusions The addition of gefitinib to RT is well tolerated. Median survival of RTOG 0211 patients treated with radiation therapy with concurrent and adjuvant gefitinib was similar to a historical control cohort treated with radiation alone.

Background Despite the widespread use of immunohistochemistry (IHC), there are no standardization guidelines that control for antibody probe variability. Here we describe the effect of variable antibody reagents in the assessment of cancer-related biomarkers by IHC. Methods Estrogen receptor (ER), epidermal growth factor receptor (EGFR) 1, and human epidermal growth factor receptor 3 (HER3) were evaluated by quantitative immunofluorescence. Correlations between ER clones 1D5, SP1, F10, and ER60c, and EGFR monoclonal 31G7, 2-18C9, H11, and 15F8, and polyclonal 2232 antibodies were assessed in 642 breast cancer patients. HER3 was measured by RTJ1, RTJ2, SGP1, M7297, RB-9211, and C-17 antibodies in 42 lung cancer patients. Survival analysis was done with the use of multiple cutoff points to reveal any prognostic classification. Results All ER antibodies were tightly correlated (Pearson’s r2 = 0.94-0.96; P < 0.0001) and western blotting confirmed their specificity in MCF-7 and BT474 cells. All EGFR antibodies but 2232 yielded specific results in western blotting; however, only 31G7 and 2-18C9 were strongly associated (Pearson’s r2 = 0.61; P < 0.0001). HER3 staining was nonspecific and nonreproducible. High EGFR–expressing patients had a worse prognosis when EGFR was measured with H11 or 31G7 (log rank P = 0.015 and P = 0.06). There was no statistically significant correlation between survival and EGFR detected by 2-18C9, 15F8, or polyclonal 2232 antibodies. Conclusions Antibody validation is a critical analytic factor that regulates IHC readings in biomarker studies. Evaluation of IHC proficiency and quality control are key components toward IHC standardization. Impact This work highlights the importance of IHC standardization and could result in the improvement of clinically relevant IHC protocols.

Localization of b-catenin in the cell is a key determinant in its decision to function as a critical mediator of cell adhesion at the surface or a transcription activator in the nucleus. SYT-SSX2 is the fusion product of the chromosomal translocation, t(X;18)(p11.2;q11.2), which occurs in synovial sarcoma, a soft tissue tumor. SYT-SSX2 is known to associate with chromatin remodeling complexes and is proposed to be involved in controlling gene expression. We report that SYT-SSX2 plays a direct role in b-catenin regulation. When expressed in mammalian cells, SYT-SSX2-induced b-catenin recruitment to the nucleus. Interestingly, known target genes of canonical Wnt were not activated as a result of SYT-SSX2 expression, nor was the nuclear localization of b-catenin due to one of the signaling pathways normally implicated in this event. b-Catenin accumulation in the nucleus led to the formation of a transcriptionally active nuclear complex that contained SYT-SSX2 and b-catenin. More importantly, depletion of SYT-SSX2 in primary synovial sarcoma cells resulted in loss of nuclear b-catenin signal and a significant decrease in its signaling activity. These results unravel a novel pathway in the control of b-catenin cellular transport and strongly suggest that SYT-SSX2 contributes to tumor development, in part through b-catenin signaling.

The matrix metalloproteinase-7 (MMP-7) gene is a target of beta-catenin transactivation. Expression of the T-cell factor, Lef-1, enhances transcriptional activation of the human MMP-7 promoter by beta-catenin, but represses activation of the mouse MMP-7 promoter, both activities through consensus Tcf binding sites. The mouse promoter has a single Tcf binding element (mTBE) located downstream of the transcriptional start site, while the human promoter has two Tcf binding elements (hTBE1, hTBE2), both located upstream of the transcriptional start. hTBE1 and hTBE2 also differ in sequence from mTBE. Here we demonstrate that positioning of mTBE, upstream or downstream of the transcriptional start site dictated whether Lef-1 functioned as an activator or repressor, respectively. Sequence differences between mTBE and hTBE sites determined the potency of these activities, with hTBE sites being weaker. Mutational analysis of mTBE showed that increased Lef-1 activity mapped to G . C base pairings at 5' and 3' ends, and correlated with a threefold increase in Lef-1 binding affinity in vitro. Heterologous promoters with high affinity binding sites were 115-fold more responsive to beta-catenin than those with low affinity sites. Converting low affinity Tcf binding sites to high affinity sites increased beta-catenin responsiveness of the mouse and human promoters by 2-3 fold, and ectopic expression of Lef-1 increased beta-catenin responsiveness for promoters with low affinity binding sequences. We concluded that sequence and position of Tcf binding sites can determine the extent of beta-catenin-Lef-1 responsiveness for beta-catenin target genes.

Purpose: This study aimed to identify molecular determinants of sensitivity of non-small cell lung cancer (NSCLC) to anti-insulin-like growth factor receptor (IGF-IR) therapy.Experimental Design: A total of 216 tumor samples were investigated, of which 165 consisted of retrospective analyses of banked tissue and an additional 51 were from patients enrolled in a phase II study of figitumumab, a monoclonal antibody against IGF-IR, in stage IIIb/IV NSCLC. Biomarkers assessed included IGF-IR, epidermal growth factor receptor, IGF-II, IGF-IIR, insulin receptor substrate 1 (IRS-1), IRS-2, vimentin, and E-cadherin. Subcellular localization of IRS-1 and phosphorylation levels of mitogenactivated protein kinase and Akt1 were also analyzed.Results: IGF-IR was differentially expressed across histologic subtypes (P = 0.04), with highest levels observed in squamous cell tumors. Elevated IGF-IR expression was also observed in a small number of squamous cell tumors responding to chemotherapy combined with figitumumab (P = 0.008). Because no other biomarker/response interaction was observed using classical histologic subtyping, a molecular approach was undertaken to segment NSCLC into mechanism-based subpopulations. Principal component analysis and unsupervised Bayesian clustering identified three NSCLC subsets that resembled the steps of the epithelial to mesenchymal transition: E-cadherin high/IRS-1 low (epithelial-like), E-cadherin intermediate/IRS-1 high (transitional), and E-cadherin low/IRS-1 low (mesenchymal-like). Several markers of the IGF-IR pathway were overexpressed in the transitional subset. Furthermore, a higher response rate to the combination of chemotherapy and figitumumab was observed in transitional tumors (71%) compared with those in the mesenchymal-like subset (32%; P = 0.03). Only one epithelial-like tumor was identified in the phase II study, suggesting that advanced NSCLC has undergone significant dedifferentiation at diagnosis.Conclusion: NSCLC comprises molecular subsets with differential sensitivity to IGF-IR inhibition.

The use of the IHC4 algorithm was validated on the TEAM trial for predicting residual risk in patients with breast cancer. These data support the use of the IHC4 algorithm clinically, but quantitative and standardized approaches need to be used.

The analysis of protein expression in tissue by immunohistochemistry (IHC) presents three significant challenges. They are (1) the time-consuming nature of pathologist-based scoring of slides; (2) the need for objective quantification and localization of protein expression; and (3) the need for a highly reproducible measurement to limit intra- and inter-observer variability. While there are a variety of commercially available platforms for automated chromagen-based and fluorescence-based image acquisition of tissue microarrays, this chapter is focused on the analysis of fluorescent images by AQUA(R) analysis (Automated QUantitative Analysis) and the solutions offered by such a method for research and diagnostics. AQUA analysis is a method for molecularly defining regions of interest or "compartments" within a tissue section. The methodology can be utilized with tissue microarrays to provide rapid, quantitative, localized, and reproducible protein expression data that can then be used to identify statistically relevant correlations in populations. Ultimately this allows for a multiplexed, objective and standardized quantitative approach for biomarker research and diagnostic assay development for protein expression in tissue.