Falette N S, Artagaveytia N, Rostan M C, Garin E, Bobin J Y, Saez S
Centre Léon Bérard, Lyon, France.
Breast Cancer Res Treat. 1994;30(3):275-82. doi: 10.1007/BF00665968.
It is well known that breast cancer cells can synthesize and secrete various growth factors that are able to stimulate tumor growth through autocrine and/or paracrine mechanisms. EGF is one of these growth factors involved in normal breast epithelial development and tumor proliferation. EGF and TGF alpha (EGF-like peptide) are produced in variable amounts and both bind to the EGF receptor (EGF-R). Previous investigation in the laboratory measuring free and occupied EGF-R sites by differential ligand binding assays had demonstrated that non-occupied and total binding sites were present in 54 and 90% of 216 breast tumor biopsies respectively. EGF-R appeared to be totally masked by endogenous ligand in 40 and 21% of estrogen receptor positive and negative tumors respectively. The aim of the present study was to check by a molecular method the expression of the EGF-R gene. The PCR method was applied to 94 tumor samples of the previous series. Total RNA was treated with 0.5 units of Rnase-free Dnase/mg of RNA to remove any contaminating DNA. We simultaneously reverse transcribed and amplified another transcript (beta-actin) as an internal standard. Both signals were present in 88 of the 94 samples while the presence of EGF-R was detected in 74 of them when assessed by radioligand assay. The findings indicate that 93% of the tumors analysed in this series expressed EGF-R mRNA, in agreement with our previous data on occupied EGF-R sites, i.e. two-fold more than by using the standard binding assay. No significant correlation was observed between the expression of the EGF-R gene and the estrogen receptor content.
众所周知，乳腺癌细胞能够合成并分泌多种生长因子，这些生长因子可通过自分泌和/或旁分泌机制刺激肿瘤生长。表皮生长因子（EGF）是这些参与正常乳腺上皮发育和肿瘤增殖的生长因子之一。EGF和转化生长因子α（EGF样肽）的产生量各不相同，且二者均与表皮生长因子受体（EGF-R）结合。实验室先前通过差异配体结合测定法测量游离和占据的EGF-R位点的研究表明，在216例乳腺肿瘤活检样本中，分别有54%和90%存在未占据和总结合位点。在雌激素受体阳性和阴性肿瘤中，分别有40%和21%的EGF-R似乎被内源性配体完全掩盖。本研究的目的是通过分子方法检测EGF-R基因的表达。PCR方法应用于先前系列的94个肿瘤样本。用0.5单位无核糖核酸酶的脱氧核糖核酸酶/毫克RNA处理总RNA，以去除任何污染的DNA。我们同时逆转录并扩增另一种转录本（β-肌动蛋白）作为内参。94个样本中有88个同时出现这两种信号，而通过放射性配体测定法评估时，其中74个检测到EGF-R的存在。研究结果表明，该系列分析的肿瘤中有93%表达EGF-R mRNA，这与我们先前关于占据的EGF-R位点的数据一致，即比使用标准结合测定法多两倍。未观察到EGF-R基因表达与雌激素受体含量之间存在显著相关性。
