Association Study of the let-7 miRNA-Complementary Site Variant in the 3′ Untranslated Region of the KRAS Gene in Stage III Colon Cancer (NCCTG N0147 Clinical Trial)

作者：Dan Sha, Adam M. Lee, Qian Shi, Steven R. Alberts, Daniel J. Sargent, Frank A. Sinicrope, Robert B. Diasio · 发表于：Clinical Cancer Research · 年份：2014 · DOI：10.1158/1078-0432.ccr-14-0069 · 被引用次数：41 · 研究领域：MicroRNA in disease regulation、Genetic factors in colorectal cancer、Colorectal Cancer Treatments and Studies

PURPOSE: A let-7 microRNA-complementary site (LCS6) polymorphism in the 3' untranslated region of the KRAS gene has been shown to disrupt let-7 binding and upregulate KRAS expression. We evaluated the LCS6 genotype and its association with KRAS mutation status, clinicopathologic features, and disease-free survival (DFS) in patients with stage III colon cancer who enrolled in a phase III clinical trial (NCCTG N0147). EXPERIMENTAL DESIGN: The LCS6 genotype was assayed by real-time PCR in DNA extracted from whole blood (n = 2,834) and compared with paired tumor tissue (n = 977). χ(2) and two-sample t tests were used to compare baseline factors and KRAS mutation status between patients defined by LCS6 variant status. Log-rank tests and multivariate Cox models assessed associations between LCS6 status and DFS, respectively. RESULTS: We identified 432 (15.2%) blood samples and 143 (14.6%) tumor samples heterozygous or homozygous for the LCS6 G-allele, and 2,402 of 2,834 (84.8%) blood samples and 834 of 977 (85.4%) tumor samples homozygous for the LCS6 T-allele. Genotype results were highly concordant (99.8%) in cases with paired blood and tumor tissue (n = 977). G-allele carriers were significantly more frequent in Caucasians versus other races (χ(2) test, P < 0.0001). The LCS6 genotype was not associated with KRAS mutation status, clinicopathologic features (all P > 0.2), or DFS (log-rank P = 0.49; HR, 0.929; 95% confidence interval, 0.76-1.14), even after combining LCS6 genotype ...