Project description:Abstract Background. Epidermal growth factor receptor (EGFR) is a targetable molecule in basal-like breast cancer, which comprises most “triple negative” breast cancer (TNBC), the only breast cancer subtype without established targeted therapy. Methods. In this randomized phase II trial, metastatic TNBC patients received the anti-EGFR antibody cetuximab (250mg/kg/week iv) with carboplatin (AUC2/wk iv) added on progression, or concomitant cetuximab + carboplatin. Molecular subtyping was done on archival specimens and those with accessible tumors provided fresh tissue, before and after 7-14 days of therapy, for microarray analyses to explore EGFR pathway inhibition. Results. Of 102 TNBC patients 74% were of the basal-like molecular subtype. Response rate to cetuximab was 6% (2/31), and was 16% (4/25) to cetuximab + carboplatin after progression. Upfront cetuximab + carboplatin produced responses in 17% (12/71); 31% responded or had prolonged disease stabilization. Time to progression was 2.1 months (95% CI 1.8-5.5) and overall survival 10.4 months (95% CI 7.7-13.1) for those treated with the combination regimen. Among 16 patients with evaluable serial biopsies, genomic patterns of the EGFR pathway showed activated status in 13 and inhibition by therapy in 5. Conclusions. While most TNBC were basal-like, a significant proportion were different subtypes. The aggressive nature of metastatic TNBC leads to limited survival. Despite a promising preclinical rationale and evidence of EGFR pathway activation in most, targeted treatment with cetuximab as a single agent had marginal activity and cetuximab added to carboplatin demonstrated modest activity. Serial biopsies as part of metastatic breast cancer studies are feasible, and this study confirmed that the EGFR pathway was inhibited by therapy in only a minority suggesting ligand-independent activation in most tumors. Tissue acquisition and drug selection based upon individualized pathway activation status should be an important part of future studies of TNBC. This series contains 36 microarrays that are from 18 patients with fresh frozen tissue available from the metastatic site. Pretreatment samples (Bx0) are available for two patients. Pretreatment and post single agent treatment (7-14 days after start of treatment with cetuximab; BxSingle) are available for three patients. Pretreatment and post combination treatment (7-14 days after start of treatment with cetuximab plus carboplatin; BxCombo) are available for eight patients. Two patients have a pretreatment sample, a sample after 7-14 days of treatment with single agent cetuximab, and a third sample 7-14 days on cetuximab plus carboplatin after switching to the combination arm upon progression on the single agent arm. Samples were hybridized with Stratagene common reference spiked with RNA from two breast cancer cell lines (ME16C and MCF-7) on Custom 1x44K Agilent microarrays. Arrays were scanned on an Axon 4000B scanner and analyzed with GenePix Pro software.

Project description:Patient-derived xenograft models are considered to represent the heterogeneity of human cancers and might be more relevant preclinical models to evaluate effective therapeutic agents. Our consortium joins efforts to extensively develop and characterize a new collection of patient-derived colorectal cancer models. From 86 unsupervised surgical colon sample collection, 54 tumors were successfully xenografted in immunodeficient mice and rats, representing 35 primary tumors, 5 peritoneal carcinosis and 14 metastases. Our histological and molecular characterization of patient tumors, first passage on mice and later passages includes the sequence of key genes involved in CRC (ie APC, KRAS, TP53), CGH array and transcriptomic analysis. This comprehensive characterization demonstrates that our collection recapitulates the clinical situation regarding the histopathological and molecular diversity of colorectal cancers. Moreover, patient tumors and corresponding models are clustering together which gives the opportunity to look for relevant signatures and comparison studies between clinical and preclinical data. Hence, we performed pharmacological monotherapy studies with standard of care for colon cancer (5-FU, oxaliplatin, irinotecan, cetuximab). Through this extensive in vivo analysis, we have compared the molecular profile with the drug sensitivity of each tumor models, and run an equivalent of a cetuximab phase II clinical trial in a preclinical setting. Our results confirm the key role of KRAS mutation in the cetuximab resistance and demonstrate that such collection could bring benefit to evaluate novel targeted therapeutic strategies and potentially help the stratification strategy for cancer patients according to molecular marker. This set correspond to 82 CGH profiles, with 7 samples from patient tumor and 75 samples from mouse xenograft at different passages P0 to P9. All hybridizations are performed with Human CGH 244K Agilent arrays (amadid 014693) in dual color with Human DNA Promega (sex matched) as reference. ID for biosources without an -Px suffix correspond to tumor patients. ID with a suffix correspond to xenograft with 0 for the first passage.

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