Institute of Pathology, University Hospital Basel, Basel, Switzerland.
Mod Pathol. 2011 Oct;24(10):1404-12. doi: 10.1038/modpathol.2011.96. Epub 2011 Jul 8.
The aim of this study was to determine: (1) the frequency of VEGFA gene locus (6p12) amplification in colorectal cancers, (2) the effect of gene amplification on clinical outcome using two independent colorectal cancer patient cohorts and (3) the relationship between amplification and KRAS or BRAF gene mutation as well as with other RAS/MAPK signalling proteins. Single-punch (n=1280; cohort 1) and multiple-punch (n=195; cohort 2) tissue microarrays were used for dual-labelling fluorescence in situ hybridization (FISH). Amplification was defined as a ratio >2 times for 6p12/centromere 6 signals. Mutation analysis of KRAS (codons 12 and 13) and BRAF (codon V600E) and immunohistochemistry for p-MAPK3/MAPK1, PEBP1, HMMR, p-AKT, PLAU, PLAUR, TP53 and VEGFA were performed on cohort 1. In cohort 1, VEGFA amplification was found in 39/1280 (3%) cases and linked to higher pT stage (P=0.022), higher tumor grade (P=0.024) and vascular invasion (P=0.003). The 5-year disease-specific survival rates were 31% (95% CI 17-46) and 57% (95% CI 54-60) for amplified and nonamplified cases, respectively (P<0.001). Results were confirmed in cohort 2. In multivariable analysis, the relative risk for amplification was 2.09 (95% CI 1.4-3.1; P<0.001) and linked to more frequent BRAF mutation (P=0.015), overexpression of p-MAPK3/MAPK1 (P=0.012) and PLAU (P=0.048) and loss of metastasis suppressor protein PEBP1 (P=0.047). VEGFA gene locus amplification highlights a small but remarkably aggressive subgroup of colorectal cancers. Further studies are needed to elucidate the potential role of amplification as a prognostic or predictive biomarker in both metastatic and nonmetastatic patients.
（1）VEGFA 基因座（6p12）在结直肠癌中的扩增频率；（2）使用两个独立的结直肠癌患者队列评估基因扩增对临床结局的影响；（3）扩增与 KRAS 或 BRAF 基因突变的关系以及与其他 RAS/MAPK 信号蛋白的关系。使用单针（n=1280；队列 1）和多针（n=195；队列 2）组织微阵列进行双标记荧光原位杂交（FISH）。扩增定义为 6p12/着丝粒 6 信号的比值>2 倍。对队列 1 中的 KRAS（密码子 12 和 13）和 BRAF（密码子 V600E）进行突变分析，并进行 p-MAPK3/MAPK1、PEBP1、HMMR、p-AKT、PLAU、PLAUR、TP53 和 VEGFA 的免疫组化检测。在队列 1 中，发现 1280 例中有 39 例（3%）发生 VEGFA 扩增，与较高的 pT 分期（P=0.022）、较高的肿瘤分级（P=0.024）和血管侵犯（P=0.003）相关。扩增组和非扩增组的 5 年疾病特异性生存率分别为 31%（95%CI 17-46）和 57%（95%CI 54-60）（P<0.001）。结果在队列 2 中得到了证实。在多变量分析中，扩增的相对风险为 2.09（95%CI 1.4-3.1；P<0.001），与更频繁的 BRAF 突变（P=0.015）、p-MAPK3/MAPK1（P=0.012）和 PLAU（P=0.048）过表达以及转移抑制蛋白 PEBP1 的缺失（P=0.047）相关。VEGFA 基因座扩增突出了一小部分但具有显著侵袭性的结直肠癌亚组。需要进一步研究以阐明扩增作为转移性和非转移性患者的预后或预测生物标志物的潜在作用。
