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Moroni M, Veronese S, Benvenuti S, Marrapese G, Sartore-Bianchi A, Di Nicolantonio F, Gambacorta M, Siena S, Bardelli AGene copy number for epidermal growth factor receptor (EGFR) and clinical response to antiEGFR treatment in colorectal cancer: a cohort study. Lancet Oncol 6: 279-286

The Falck Division of Medical Oncology, Ospedale Niguarda Ca' Granda, Milan, Italy.
The Lancet Oncology (Impact Factor: 24.73). 05/2005; 6(5):279-86. DOI: 10.1016/S1470-2045(05)70102-9
Source: PubMed

ABSTRACT The antiepidermal growth factor receptor (antiEGFR) monoclonal antibodies cetuximab and panitumumab have good clinical activity in about 10% of patients with metastatic colorectal cancer that is resistant to chemotherapy. The molecular mechanisms underlying clinical response or resistance to these agents are unknown.
Tumours from 31 patients with metastatic colorectal cancer who had either an objective response (n=10) or stable disease or progressive disease (n=21) after treatment with cetuximab or panitumumab were screened for genetic changes in EGFR or its immediate intracellular effectors. Specifically, we assessed the EGFR copy number and the mutation profile of the EGFR catalytic domain and of selected exons in KRAS, BRAF, and PIK3CA.
Eight of nine of patients with objective responses who were assessable by fluorescence in-situ hybridisation (FISH) had an increased EGFR copy number. By contrast, one of 21 non-responders assessable by FISH had an increased EGFR copy number (p<0.0001 for responders vs non-responders, Fisher's exact test). The mutation status of the EGFR catalytic domain and its immediate downstream effectors PIK3CA, KRAS, and BRAF did not correlate with disease response. In colorectal-cancer cell lines, the concentration of cetuximab that completely inhibited proliferation of cells with amplified EGFR copy number did not affect proliferation of cells with unamplified EGFR.
We propose that the response to antiEGFR treatment has a genetic basis and suggest that patients might be selected for treatment on the basis of EGFR copy number.

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    • "EGFR gene copy number (GCN) increase has been linked to anti-EGFR treatment response. Most studies have shown an association between GCN level and clinical benefit, progression free survival (PFS), and in some cases, with overall survival (OS) [4]–[6]. However, EGFR GCN is not currently utilized in the clinical context because of technical obstacles and considerable variation between the scoring systems [7]. "
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    ABSTRACT: Anti-EGFR therapy is commonly used to treat colorectal cancer (CRC), although only a subset of patients benefit from the treatment. While KRAS mutation predicts non-responsiveness, positive predictive markers are not in clinical practice. We previously showed that immunohistochemistry (IHC)-guided EGFR gene copy number (GCN) analysis may identify CRC patients benefiting from anti-EGFR treatment. Here we tested the predictive value of such analysis in chemorefractory metastatic CRC, elucidated EGFR GCN heterogeneity within the tumors, and evaluated the association between EGFR GCN, KRAS status, and anti-EGFR antibody response in CRC cell lines. The chemorefractory patient cohort consisted of 54 KRAS wild-type (WT) metastatic CRC patients. EGFR GCN status was analyzed by silver in situ hybridization using a cut-off value of 4.0 EGFR gene copies/cell. KRAS-WT and KRAS mutant CRC cell lines with different EGFR GCN were used in in vitro studies. The chemorefractory CRC tumors with EGFR GCN increase (≥4.0) responded better to anti-EGFR therapy than EGFR GCN (<4.0) tumors (clinical benefit, P = 0.0004; PFS, HR = 0.23, 95% CI 0.12-0.46). EGFR GCN counted using EGFR IHC guidance was significantly higher than the value from randomly selected areas verifying intratumoral EGFR GCN heterogeneity. In CRC cell lines, EGFR GCN correlated with EGFR expression. Best anti-EGFR response was seen with KRAS-WT, EGFR GCN = 4 cells and poorest response with KRAS-WT, EGFR GCN = 2 cells. Anti-EGFR response was associated with AKT and ERK1/2 phosphorylation, which was effectively inhibited only in cells with KRAS-WT and increased EGFR GCN. In conclusion, IHC-guided EGFR GCN is a promising predictor of anti-EGFR treatment efficacy in chemorefractory CRC.
    PLoS ONE 06/2014; 9(6):e99590. DOI:10.1371/journal.pone.0099590 · 3.23 Impact Factor
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    • "In addition to identifying gene mutations, there is also a need for detection of protein expression and gene amplification of targeted molecules on primary tumor cells for further stratification of patients [4]. To optimize treatment, real-time monitoring of tumors over the course of the treatment, especially at the point of treatment failure, is necessary. "
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    ABSTRACT: Background Personalized cancer treatment relies on the accurate detection of actionable genomic aberrations in tumor cells. Circulating tumor cells (CTCs) could provide an alternative genetic resource for diagnosis; however, the technical difficulties in isolating and analyzing rare CTCs have limited progress to date. In this preclinical study, we aimed to develop an improved capture system for molecular characterization of CTCs based on a novel cell sorting technology. Methods We developed a cell capture platform using On-chip Sort (On-Chip Biotechnologies), a novel bench-top cell sorter equipped with a disposable microfluidic chip. Spike-in experiments comprising a series of lung cancer cell lines with varying epithelial cell adhesion molecule (EpCAM) expression levels were conducted to assess the capture and purification efficiency of the platform. Samples were negatively enriched using anti-CD45-coated magnetic beads to remove white blood cells, followed by sample fixation and labeling. The enriched and labeled samples were then sorted by On-chip Sort based on cytokeratin, vimentin, and CD45 expression. Captured cells were immediately subjected to whole genome amplification followed by mutation analysis using deep targeted sequencing, and copy number analysis using quantitative polymerase chain reaction (qPCR). Results Spike-in experiments revealed an excellent overall mean capture rate of 70.9%. A 100% success rate in the detection of EGFR, KRAS and BRAF mutations from captured cells was achieved using pyrosequencing and deep sequencing. The mutant variant detection rates were markedly higher than those obtained with the CellSearch profile kit. qPCR analysis of amplified DNA demonstrated reproducible detection of copy number changes of the EGFR in captured tumor cells. Conclusions Using a novel cell sorter, we established an efficient and convenient platform for the capture of CTCs. Results of a proof-of-principle preclinical study indicated that this platform has potential for the molecular characterization of captured CTCs from patients.
    Journal of Translational Medicine 05/2014; 12(1):143. DOI:10.1186/1479-5876-12-143 · 3.99 Impact Factor
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    • "There is also a small, and rather controversial, literature on individual differences in brain structure related to variables like gender, sexual orientation, and cognitive function (some examples: Holloway and de Lacoste, 1986; Witelson, 1989, 1991; McCormick et al., 1990; Levay, 1991; Witelson and Goldsmith, 1991; Allen and Gorski, 1992; Witelson and Kigar, 1992; Shaywitz et al., 1995; Witelson et al., 1995, 1999). While often neglected in neuroscience, the recognition of individual differences is of increasing concern in the development of individualized medical treatments based on genetic profiles (van’t Veer et al., 2002; Chang et al., 2003; Moroni et al., 2005; Sartore-Bianchi et al., 2007). "
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