EGFR gene amplification and KRAS mutation predict response to combination targeted therapy in metastatic colorectal cancer Journal Article


Authors: Khan, S. A.; Zeng, Z.; Shia, J.; Paty, P. B.
Article Title: EGFR gene amplification and KRAS mutation predict response to combination targeted therapy in metastatic colorectal cancer
Abstract: Genetic variability in KRAS and EGFR predicts response to cetuximab in irinotecan refractory colorectal cancer. Whether these markers or others remain predictive in combination biologic therapies including bevacizumab is unknown. We identified predictive biomarkers from patients with irinotecan refractory metastatic colorectal cancer treated with cetuximab plus bevacizumab. Patients who received cetuximab plus bevacizumab for irinotecan refractory colorectal cancer in either of two Phase II trials conducted were identified. Tumor tissue was available for 33 patients. Genomic DNA was extracted and used for mutational analysis of KRAS, BRAF, and p53 genes. Fluorescence in situ hybridization was performed to assess EGFR copy number. The status of single genes and various combinations were tested for association with response. Seven of 33 patients responded to treatment. KRAS mutations were found in 14/33 cases, and 0 responded to treatment (p = 0.01). EGFR gene amplification was seen in 3/33 of tumors and in every case was associated with response to treatment (p < 0.001). TP53 and BRAF mutations were found in 18/33 and 0/33 tumors, respectively, and there were no associations with response to either gene. EGFR gene amplification and KRAS mutations are predictive markers for patients receiving combination biologic therapy of cetuximab plus bevacizumab for metastatic colorectal cancer. One marker or the other is present in the tumor of half of all patients allowing treatment response to be predicted with a high degree of certainty. The role for molecular markers in combination biologic therapy seems promising. © 2016, Arányi Lajos Foundation.
Keywords: adult; clinical article; controlled study; human tissue; treatment response; aged; gene mutation; human cell; bevacizumab; cancer growth; skin toxicity; colorectal cancer; biological marker; gene; metastasis; progression free survival; phase 2 clinical trial; gene amplification; epidermal growth factor receptor; genetic association; genetic variability; mutational analysis; cetuximab; protein p53; irinotecan; fluorescence in situ hybridization; egfr; kras; egfr gene; oncogene k ras; k ras protein; p53 gene; copy number variation; metastatic colorectal cancer; response evaluation criteria in solid tumors; human; male; female; article
Journal Title: Pathology & Oncology Research
Volume: 23
Issue: 3
ISSN: 1219-4956
Publisher: Springer  
Date Published: 2017-07-01
Start Page: 673
End Page: 677
Language: English
DOI: 10.1007/s12253-016-0166-2
PROVIDER: scopus
PMCID: PMC5451302
PUBMED: 28025786
DOI/URL:
Notes: Article -- Export Date: 3 July 2017 -- Source: Scopus
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  1. Philip B Paty
    496 Paty
  2. Zhaoshi Zeng
    87 Zeng
  3. Jinru Shia
    715 Shia