Analytic validation of a clinical-grade PTEN immunohistochemistry assay in prostate cancer by comparison with PTEN FISH.
Analytic validation of a clinical-grade PTEN immunohistochemistry assay in prostate cancer by comparison with PTEN FISH.
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DOI：
10.1038/modpathol.2016.88
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发表时间：
2016-08
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影响因子：
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通讯作者：
Squire JA
中科院分区：
文献类型：
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作者：
Lotan TL;Wei W;Ludkovski O;Morais CL;Guedes LB;Jamaspishvili T;Lopez K;Hawley ST;Feng Z;Fazli L;Hurtado-Coll A;McKenney JK;Simko J;Carroll PR;Gleave M;Lin DW;Nelson PS;Thompson IM;True LD;Brooks JD;Lance R;Troyer D;Squire JA
PTEN缺失是前列腺癌一个有前景的预后和预测生物标志物。由于PTEN基因缺失最常见，我们开发了一种临床分级、自动化和廉价的免疫组织化学方法来检测PTEN缺失。我们研究了PTEN免疫组织化学相对于四色荧光原位杂交(FISH)检测731例前列腺癌多机构队列中PTEN基因缺失的敏感性和特异性。完整的PTEN免疫染色对PTEN基因缺失的特异性为91%(549/602例PTEN基因2拷贝的FISH免疫组织化学检测显示PTEN基因完整表达)，对PTEN基因纯合性缺失的敏感性为97%(在65/67例纯合性缺失的肿瘤中免疫组织化学检测PTEN蛋白缺失)。PTEN免疫组织化学检测半合子PTEN基因缺失的敏感性为65%，其中40/62例半合子肿瘤有蛋白缺失。我们回顾了53例免疫组织化学显示PTEN蛋白丢失，FISH显示PTEN基因2个完整拷贝的病例。复查发现6%(3/53)免疫组织化学模糊丢失，34%(18/53)两种方法未能分析同一肿瘤区域。在其余不一致的病例中，41%(13/32)表现为PTEN基因半合子缺失(n=8)或纯合子缺失(n=5)，多数病例(11/13)为局灶性缺失。其余19例经FISH检测有2个PTEN基因拷贝，代表真正不一致的病例。我们的自动PTEN免疫组织化学检测是检测纯合PTEN基因缺失的一种敏感方法。免疫组织化学筛查对于确定肿瘤腺体中存在异质性PTEN基因缺失的病例特别有用。在PTEN基因拷贝数正常或半合子的肿瘤中，突变、小的插入或缺失和/或表观遗传或microRNA介导的机制可能导致PTEN蛋白丢失。
PTEN loss is a promising prognostic and predictive biomarker in prostate cancer. Because it occurs most commonly via PTEN gene deletion, we developed a clinical-grade, automated and inexpensive immunohistochemical assay to detect PTEN loss. We studied the sensitivity and specificity of PTEN immunohistochemistry relative to 4-color fluorescence in situ hybridization (FISH) for detection of PTEN gene deletion in a multi-institutional cohort of 731 primary prostate tumors. Intact PTEN immunostaining was 91% specific for absence of PTEN gene deletion, (549/602 tumors with 2 copies of the PTEN gene by FISH showed intact expression of PTEN by immunohistochemistry) and 97% sensitive for presence of homozygous PTEN gene deletion (absent PTEN protein expression by immunohistochemistry in 65/67 tumors with homozygous deletion). PTEN immunohistochemistry was 65% sensitive for presence of hemizygous PTEN gene deletion, with protein loss in 40/62 hemizygous tumors. We reviewed the 53 cases where immunohistochemistry showed PTEN protein loss and FISH showed 2 intact copies of the PTEN gene. On re-review, there was ambiguous immunohistochemistry loss in 6% (3/53) and failure to analyze the same tumor area by both methods in 34% (18/53). Of the remaining discordant cases, 41% (13/32) revealed hemizygous (n=8) or homozygous (n=5) PTEN gene deletion that was focal in most cases (11/13). The remaining 19 cases had 2 copies of the PTEN gene by FISH, representing truly discordant cases. Our automated PTEN immunohistochemistry assay is a sensitive method for detection of homozygous PTEN gene deletions. Immunohistochemistry screening is particularly useful to identify cases with heterogeneous PTEN gene deletion in a subset of tumor glands. Mutations, small insertions or deletions and/or epigenetic or microRNA-mediated mechanisms may lead to PTEN protein loss in tumors with normal or hemizygous PTEN gene copy number.