Immunoassay for wild-type protein in lymphocytes predicts germline mutations in patients at risk for hereditary colorectal cancer
Immunoassay for wild-type protein in lymphocytes predicts germline mutations in patients at risk for hereditary colorectal cancer
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DOI：
10.1016/j.lab.2003.10.001
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发表时间：
2004-01-01
期刊：
影响因子：
--
通讯作者：
Boman, BM
中科院分区：
文献类型：
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作者：
Fields, JZ;Gao, ZP;Boman, BM
以结直肠癌（CRC）为例，我们提出的假设，野生型（全长）蛋白质的定量免疫测定可用于识别遗传性疾病的性状载体。在遗传性CRC的情况下，这涉及识别在错配修复（MMR）基因（主要是hMSH 2或hMLH 1）或腺瘤性结肠息肉病（APC）基因中具有种系突变的个体。由于野生型蛋白的表达应反映野生型基因的剂量，我们预测，携带种系突变的个体在淋巴细胞中相应全长蛋白的表达将减少约50%。在这项初步研究中，我们测试了从对照中建立的淋巴母细胞样细胞系。和患有遗传性CRC或处于遗传性CRC高风险的个体：9个系来自健康的未受影响的个体; 4个系来自家族性腺瘤性息肉病家族中受影响的成员（具有已知的生殖系APC突变）; 42个系来自我们的家族性CRC登记中的CRC患者（遗传性非息肉病性结肠癌的风险增加，如通过家族史、腺瘤或癌诊断时的年龄和其他临床标准评估的）。对于MSH 2和MLH 1，我们使用蛋白质印迹;对于APC，我们使用免疫沉淀。所有家族性腺瘤性息肉病系的免疫沉淀全长APC蛋白约减少50%。来自家族性CRC登记患者的一些细胞系（42个中的7个）在蛋白质印迹上显示MSH 2或MLH 1（相对于其他蛋白质）的减少（平均46%）。所有7个随后被证明含有生殖系MMR突变。我们的结论是：（1）由于大多数预期的CRC致病性生殖系突变是截短引起的，野生型蛋白的免疫测定应该能够识别大多数具有遗传性CRC致病性状的个体;（2）这些测定比目前用于遗传性CRC性状的突变检测试验更实用和便宜，具有商业开发潜力，可对高风险患者及其家人进行基础广泛的人群筛查，并有可能挽救生命和节省医疗费用;（3）这种策略可能对其他遗传性癌症甚至其他遗传性疾病有用;（4）我们的方法有可能极大地有益于癌症控制的公共卫生计划。
Using colorectal cancer (CRC) as an example, we present the hypothesis that quantitative immunoassays for wild-type (full-length) proteins can be used to identify carriers of traits for hereditary diseases. In the case of hereditary CRC, this involves identifying individuals with germline mutations in a mismatch-repair (MMR) gene (mainly hMSH2 or hMLH1) or in the adenomatous polyposis coli (APC) gene. Because expression of wild-type protein should reflect wild-type gene dosage, we predicted that individuals harboring a germline mutation will have a reduction of approximately 50% in expression in lymphocytes of the corresponding full-length protein. In this pilot study, we tested lymphoblastoid cell lines that had been established from controls. and individuals with, or at high risk for, hereditary CRC: 9 lines from healthy, unaffected individuals; 4 from affected members in familial adenomatous polyposis families (with known germ-line APC mutation); 42 from CRC patients in our Familial CRC Registry (increased risk of hereditary nonpolyposis colon cancer as assessed by family history, age at adenoma or carcinoma diagnosis, and other clinical criteria). For MSH2 and MLH1 we used western blots; for APC we used immunoprecipitation. All familial adenomatous polyposis lines had about 50% less immunoprecipitable full-length APC protein. Some cell lines (7 of 42) from Familial CRC Registry patients showed on western blots a reduction (mean 46%) in either MSH2 or MLH1 (relative to the other protein). All 7 subsequently were proved to contain a germline MMR mutation. We conclude that (1) because most of the expected CRC-causlng germ line mutations are truncation-causing, immunoassays for wild-type protein should be able to identify most individuals with hereditary CRC-causing traits; (2) these assays, which are more practical and inexpensive than current mutation-detecting tests for hereditary CRC traits, have the potential for commercial development into broad-based population screens of high-risk patients and their families and the potential to save both lives and health-care dollars; (3) this strategy may be useful for other hereditary cancers and even other hereditary diseases; (4) our approach has the potential to greatly benefit public-health programs for cancer control.