Dataset Information

Heterogeneous EGFR gene copy number increase is common in colorectal cancer and defines response to anti-EGFR therapy.

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.

SUBMITTER: Algars A

PROVIDER: S-EPMC4062406 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Heterogeneous EGFR gene copy number increase is common in colorectal cancer and defines response to anti-EGFR therapy.

Ålgars Annika A Avoranta Tuulia T Österlund Pia P Lintunen Minnamaija M Sundström Jari J Jokilehto Terhi T Ristimäki Ari A Ristamäki Raija R Carpén Olli O

PloS one 20140618 6

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 EG ...[more]

PMID: 24940619

Similar Datasets

Project description:BackgroundEpidermal growth factor receptor gene copy number (EGFR GCN) has been heavily investigated as a potential predictive biomarker for the treatment of metastatic colorectal cancer (mCRC) with anti-EGFR monoclonal antibodies (MAbs). The objective of this study was to systematically review current evidences on this issue.MethodsPubMed, EMBASE, The Cochrane Library, Chinese Biomedical Literature Database, Wanfang Data, and the conference abstracts of American Society of Clinical Oncology and European Society of Medical Oncology were comprehensively searched. Studies that reported the objective response rate (ORR), progression-free survival, and/or overall survival of mCRC patients treated with anti-EGFR MAbs, stratified by EGFR GCN status, were included. The effect measures for binary outcome (response) and time-to-event outcomes (progression-free survival and overall survival) were risk difference and hazard ratio, respectively. Statistical heterogeneity among the studies was assessed by the Cochran's Q-test and the I2 statistic. If appropriate, a quantitative synthesis of data from different studies would be conducted with a random-effects model.ResultsNineteen eligible studies were identified. The criteria for increased EGFR GCN (GCN+) were highly inconsistent across different studies. The prevalence of GCN?+?ranged from 6.9% to 88.9%, and the difference in ORR between patients with GCN?+?and those with non-increased EGFR GCN (GCN-) varied from -28% to 84%. Because of the significant heterogeneity, no quantitative synthesis of data was performed. There was a general trend towards higher ORR in patients with GCN+. The difference in ORRs between patients with GCN?+?and those with GCN- was even greater in KRAS wild-type patients, while in KRAS mutated patients the difference often did not exist. Almost all patients with EGFR amplification responded to the treatment. However, the prevalence of EGFR amplification was generally low. Incomplete data on progression-free survival and overall survival seemingly supported the findings on ORR.ConclusionsAlthough increased EGFR GCN is generally associated with a better outcome of anti-EGFR MAbs treatment, especially among patients with wild-type KRAS, the clinical utility of this biomarker for selecting recipients of anti-EGFR MAbs would be severely limited by the heterogeneous scoring system and the poor reproducibility of EGFR GCN enumeration due to technical reasons.

Dataset Information

Heterogeneous EGFR gene copy number increase is common in colorectal cancer and defines response to anti-EGFR therapy.

Publications

Heterogeneous EGFR gene copy number increase is common in colorectal cancer and defines response to anti-EGFR therapy.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure