Institute of Pathology, University Hospital Heidelberg, Heidelberg, Germany.
Institute of Pathology, Charité University Hospital, Berlin, Germany.
Genes Chromosomes Cancer. 2018 Feb;57(2):70-79. doi: 10.1002/gcc.22509. Epub 2017 Nov 16.
During the course of disease, many cancer patients eventually present with metastatic disease including peritoneal or pleural spread. In this context, cytology specimens derived from ascites or pleural effusion may help to differentiate malignant from benign conditions and sometimes yield diagnosis of a malignancy. However, even when supported by immunohistochemistry, cytological interpretation can be challenging, especially if tumor cellularity is low. Here, we investigated whether targeted deep sequencing of formalin-fixed and paraffin embedded (FFPE) cytology specimens of cancer patients is feasible, and has diagnostic and clinical impact. To this end, a cohort of 20 matched pairs was compiled, each comprising a cytology sample (FFPE cell block) and at least one biopsy/surgical resection specimen serving as benchmark. In addition, 5 non-malignant effusions were sequenced serving as negative-controls. All samples yielded sufficient libraries and were successfully subjected to targeted sequencing employing a semiconductor based next-generation sequencing platform. Using gene panels of different size and composition, including the Oncomine Comprehensive Assay, for targeted sequencing, somatic mutations were detected in the tissue of all 20 cases. Of these, 15 (75%) harbored mutations that were also detected in the corresponding cytology samples. In four of these cases (20%), additional private mutations were detected in either cytology or tissue samples, reflecting spatiotemporal tumor evolution. Of the five remaining cases, three (15%) showed wild type alleles in cytology material whereas tumor tissue had mutations in interrogated genes. Two cases were discordant, showing different private mutations in the cytology and in the tissue sample, respectively. In summary, sequencing of cytology specimens (FFPE cell block) reflecting spatiotemporal tumor evolution is feasible and yields adjunct genetic information that may be exploitable for diagnostics and therapy.
在疾病过程中，许多癌症患者最终出现转移性疾病，包括腹膜或胸膜扩散。在这种情况下，来自腹水或胸腔积液的细胞学标本有助于区分恶性和良性情况，有时还可以诊断恶性肿瘤。然而，即使有免疫组织化学的支持，细胞学解释也具有挑战性，尤其是当肿瘤细胞密度较低时。在这里，我们研究了福尔马林固定和石蜡包埋（FFPE）的癌症患者细胞学标本的靶向深度测序是否可行，以及是否具有诊断和临床影响。为此，我们汇编了一组 20 对匹配的样本，每对样本包括一个细胞学样本（FFPE 细胞块）和至少一个活检/手术切除样本作为基准。此外，还对 5 个非恶性积液进行了测序作为阴性对照。所有样本都产生了足够的文库，并成功地采用基于半导体的下一代测序平台进行了靶向测序。使用不同大小和组成的基因面板，包括 Oncomine Comprehensive Assay，进行靶向测序，在所有 20 个病例的组织中都检测到了体细胞突变。其中，15 例（75%）的细胞中也检测到了与相应细胞学样本中相同的突变。在这 4 例（20%）中，在细胞学或组织样本中检测到了额外的私有突变，反映了时空肿瘤进化。在其余的 5 例中，3 例（15%）在细胞学材料中显示野生型等位基因，而肿瘤组织中则有突变基因。两种情况是不一致的，分别在细胞学和组织样本中显示了不同的私有突变。总之，对反映时空肿瘤进化的细胞学标本（FFPE 细胞块）进行测序是可行的，并且产生了辅助遗传信息，可用于诊断和治疗。
