scholarly journals Current Approaches for Predicting a Lack of Response to Anti-EGFR Therapy inKRASWild-Type Patients

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Tze-Kiong Er ◽  
Chih-Chieh Chen ◽  
Luis Bujanda ◽  
Marta Herreros-Villanueva

Targeting epidermal growth factor receptor (EGFR) has been one of the most effective colorectal cancer strategies. Anti-EGFR antibodies function by binding to the extracellular domain of EGFR, preventing its activation, and ultimately providing clinical benefit.KRASmutations in codons 12 and 13 are recognized prognostic and predictive biomarkers that should be analyzed at the clinic prior to the administration of anti-EGFR therapy. However, still an important fraction ofKRASwild-type patients do not respond to the treatment. The identification of additional genetic determinants of primary or secondary resistance to EGFR targeted therapy for further improving the selection of patients is urgent. Herein, we review the latest published literature highlighting the most important genes that may predict resistance to anti-EGFR monoclonal antibodies in colorectal cancer patients. According to the available findings, the evaluation ofBRAF,NRAS,PIK3CA, andPTENstatus could be the right strategy to select patients who are likely to respond to anti-EGFR therapies. In the future, the combination of those biomarkers will help establish consensus that can be introduced into clinical practice.

2005 ◽  
Vol 23 (9) ◽  
pp. 1803-1810 ◽  
Author(s):  
Ki Young Chung ◽  
Jinru Shia ◽  
Nancy E. Kemeny ◽  
Manish Shah ◽  
Gary K. Schwartz ◽  
...  

Purpose To establish evidence of activity, or lack thereof, of cetuximab-based therapy in patients with refractory colorectal cancer with tumors that do not demonstrate epidermal growth factor receptor (EGFR) expression by immunohistochemistry (IHC). Patients and Methods Pharmacy computer records were reviewed to identify all patients who received cetuximab at Memorial Sloan-Kettering Cancer Center in a nonstudy setting during the first 3 months of cetuximab's commercial availability. Medical records of these patients were then reviewed to identify colorectal cancer patients who had experienced failure with a prior irinotecan-based regimen and who had a pathology report indicating an EGFR-negative tumor by IHC. Pathology slides from these patients were reviewed by a reference pathologist to confirm EGFR negativity, and computed tomography scans during cetuximab-based therapy were reviewed by a reference radiologist. Response rates were reported using WHO criteria. Results Sixteen chemotherapy-refractory, EGFR-negative colorectal cancer patients who received cetuximab in a nonstudy setting were identified. Fourteen of these patients received cetuximab plus irinotecan, and two received cetuximab monotherapy. In the 16 patients, four major objective responses were seen (response rate, 25%; 95% CI, 4% to 46%). Conclusion Colorectal cancer patients with EGFR-negative tumors have the potential to respond to cetuximab-based therapies. EGFR analysis by current IHC techniques does not seem to have predictive value, and selection or exclusion of patients for cetuximab therapy on the basis of currently available EGFR IHC does not seem warranted.


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