TY - JOUR
T1 - Epidermal growth factor receptor R521K polymorphism shows favorable outcomes in KRAS wild-type colorectal cancer patients treated with cetuximab-based chemotherapy
AU - Hsieh, Yao Yu
AU - Tzeng, Cheng Hwai
AU - Chen, Ming Huang
AU - Chen, Po Min
AU - Wang, Wei Shu
PY - 2012/4
Y1 - 2012/4
N2 - The R521K polymorphism of epidermal growth factor receptor has attenuated affinity in ligand binding and proto-oncogene induction, which may affect the efficacy of cetuximab. We analyzed the effect of this polymorphism on the outcome of 112 patients with KRAS wild-type metastatic colorectal carcinoma treated with first-line cetuximab plus FOLFOX-4. The associations of this polymorphism with vascular endothelial growth factor (VEGF) expression and clinicopathologic characteristics were also examined. The results showed that the frequencies of the G/G, G/A, and A/A genotypes were 32.1% (n = 36), 42.9% (n = 48), and 25.0% (n = 28), respectively. A marked decrease in VEGF expression levels (66.7% vs 28.9%, P < 0.01) was observed in patients with 521A allele variants (Arg/Lys or Lys/Lys), which were associated with a decreased tumor size (55.6% vs 31.6%, P = 0.02), good histological differentiation (63.9% vs 85.5%, P = 0.01), decreased lymphovascular invasion (69.4% vs 39.5%, P < 0.01), and a higher response rate to cetuximab plus FOLFOX treatment (55.6% vs 78.9%, P = 0.01). In addition, this polymorphism was associated with a longer progression-free period (P = 0.001) and overall survival (P = 0.001). By multivariate analysis, this polymorphism was also identified as an independent prognostic factor. These data suggest that the R521K polymorphism of epidermal growth factor receptor, by reducing its activation and a consequential downregulation of its target genes, including VEGF, could be a key determinant of an increased response to cetuximab-based chemotherapy and a longer survival for KRAS wild-type colorectal carcinoma patients.
AB - The R521K polymorphism of epidermal growth factor receptor has attenuated affinity in ligand binding and proto-oncogene induction, which may affect the efficacy of cetuximab. We analyzed the effect of this polymorphism on the outcome of 112 patients with KRAS wild-type metastatic colorectal carcinoma treated with first-line cetuximab plus FOLFOX-4. The associations of this polymorphism with vascular endothelial growth factor (VEGF) expression and clinicopathologic characteristics were also examined. The results showed that the frequencies of the G/G, G/A, and A/A genotypes were 32.1% (n = 36), 42.9% (n = 48), and 25.0% (n = 28), respectively. A marked decrease in VEGF expression levels (66.7% vs 28.9%, P < 0.01) was observed in patients with 521A allele variants (Arg/Lys or Lys/Lys), which were associated with a decreased tumor size (55.6% vs 31.6%, P = 0.02), good histological differentiation (63.9% vs 85.5%, P = 0.01), decreased lymphovascular invasion (69.4% vs 39.5%, P < 0.01), and a higher response rate to cetuximab plus FOLFOX treatment (55.6% vs 78.9%, P = 0.01). In addition, this polymorphism was associated with a longer progression-free period (P = 0.001) and overall survival (P = 0.001). By multivariate analysis, this polymorphism was also identified as an independent prognostic factor. These data suggest that the R521K polymorphism of epidermal growth factor receptor, by reducing its activation and a consequential downregulation of its target genes, including VEGF, could be a key determinant of an increased response to cetuximab-based chemotherapy and a longer survival for KRAS wild-type colorectal carcinoma patients.
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U2 - 10.1111/j.1349-7006.2012.02225.x
DO - 10.1111/j.1349-7006.2012.02225.x
M3 - Article
C2 - 22321154
AN - SCOPUS:84862776964
SN - 1347-9032
VL - 103
SP - 791
EP - 796
JO - Cancer Science
JF - Cancer Science
IS - 4
ER -