Hunt Jennifer L, Swalsky Patricia, Sasatomi E, Niehouse Laura, Bakker Anke, Finkelstein Sydney D
Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA.
Arch Pathol Lab Med. 2003 Feb;127(2):213-7. doi: 10.5858/2003-127-213-MAMGAT.
A recurring problem in surgical pathology practice is specimen mix-up and floater contamination. While many cases can be resolved histologically, a significant number remain unclear and may have serious clinical and medicolegal implications.
To design a microdissection and genotyping assay to identify contaminating floater tissues in paraffin-embedded tissues that is optimized for small samples, and to use the assay to resolve a series of clinical cases with floater tissues.
Twenty-one cases of possible tissue floater contamination in paraffin-embedded tissue blocks were included. Using 4 unstained, 4-microm-thick histologic sections, multiple sites were microdissected under direct visualization either by hand or by laser capture microdissection. Nonneoplastic and neoplastic tissues were sampled. Polymerase chain reaction was performed for a panel of 10 polymorphic microsatellite markers at 1p34, 3p26, 5q21, 9p21, 10q23, and 17p13. Allele size and content were analyzed semiquantitatively by fluorescent capillary electrophoresis, and the genotypes for the tissues in the paraffin-embedded tissue blocks were compared for identity.
Tissue identification was successful in all cases, despite small tissue sample size and fixation effects. Comparative analysis of neoplastic tissue floaters and the presumptive source tumor was performed when possible to control for possible allelic loss or microsatellite instability.
Microdissection and genotyping are effective and reliable means to objectively resolve problems of possible floater contamination. Even minute tissue samples provide sufficient DNA template for polymerase chain reaction microsatellite analysis. Because of the potential clinical implications of floaters, we recommend that all suspected floaters that would change a diagnosis from benign to malignant be subjected to genotyping assay to confirm the identity of the floater tissue.
手术病理实践中一个反复出现的问题是标本混淆和漂浮物污染。虽然许多病例可以通过组织学方法解决，但仍有相当数量的病例情况不明，可能具有严重的临床和法医学意义。
设计一种显微切割和基因分型检测方法，以识别石蜡包埋组织中污染的漂浮组织，该方法针对小样本进行了优化，并使用该检测方法解决一系列存在漂浮组织的临床病例。
纳入21例石蜡包埋组织块中可能存在组织漂浮物污染的病例。使用4张未染色的4微米厚组织切片，通过手工或激光捕获显微切割在直接可视化下对多个部位进行显微切割。采集非肿瘤组织和肿瘤组织样本。针对位于1p34、3p26、5q21、9p21、10q23和17p13的一组10个多态性微卫星标记进行聚合酶链反应。通过荧光毛细管电泳对等位基因大小和含量进行半定量分析，并比较石蜡包埋组织块中组织的基因型是否一致。
尽管组织样本量小且存在固定效应，但所有病例的组织鉴定均成功。在可能的情况下，对肿瘤组织漂浮物和推定的原发肿瘤进行比较分析，以控制可能的等位基因缺失或微卫星不稳定性。
显微切割和基因分型是客观解决可能的漂浮物污染问题的有效且可靠的方法。即使是微小的组织样本也能为聚合酶链反应微卫星分析提供足够的DNA模板。由于漂浮物可能具有临床意义，我们建议对所有可能将诊断从良性改变为恶性的疑似漂浮物进行基因分型检测，以确认漂浮组织的身份。
