University of Massachusetts Medical School, Worcester, Massachusetts.
Department of Pathology, University of Massachusetts Memorial Health Care, Worcester, Massachusetts.
J Am Soc Cytopathol. 2021 Jan-Feb;10(1):94-102. doi: 10.1016/j.jasc.2020.10.001. Epub 2020 Oct 14.
Cytology and cystoscopy are used to detect urothelial carcinoma (UC), but together they still fail to detect some UC cases and are not suitable for screening asymptomatic individuals. Mutations are present in more than 98% of UC, mutations have therapeutic significance, and they can be detected by next generation sequencing (NGS) in urine samples. We review the role of NGS in UC detection.
Comprehensive literature review on UC genetics, economics of NGS, and previous reports of UC detection by NGS.
The raw costs of NGS have decreased to about 14,000 base pairs per penny, making it appear economically feasible to use NGS widely. Reported NGS assays fall short of predicted sensitivity. Decreased sensitivity is attributed to a low frequency of mutant alleles in many urine samples. Attempts to increase the percentage of mutant alleles, by using cell-free urinary DNA, or by using cell sorting and microfluidics, have been unsuccessful or remain unproven. However, cytologic examination can immediately enable NGS: Urine cytologies with sufficient proportions of abnormal cells could be directly triaged to NGS with high sensitivity for UC detection. For cases with a low proportion of abnormal cells, cytologically targeted microdissection of cells for NGS should maintain sensitivity and decrease sequencing costs. Cytologically targeted urothelial cells for NGS could allow a screening test for low grade UC.
Cytology is immediately poised to allow NGS to improve the diagnosis of UC, allowing NGS to be an ancillary test for atypical cytologies, and potentially allowing a screening test for low-grade UC.
细胞学和膀胱镜检查用于检测尿路上皮癌（UC），但它们结合起来仍未能检测到一些 UC 病例，也不适合用于无症状个体的筛查。超过 98%的 UC 存在突变，这些突变具有治疗意义，可以通过下一代测序（NGS）在尿液样本中检测到。我们回顾了 NGS 在 UC 检测中的作用。
对 UC 遗传学、NGS 的经济学以及之前通过 NGS 检测 UC 的报告进行全面的文献回顾。
NGS 的原始成本已降至每碱基 14000 美元左右，使其看起来广泛使用 NGS 在经济上是可行的。报道的 NGS 检测在灵敏度上存在不足。灵敏度降低归因于许多尿液样本中突变等位基因的频率较低。通过使用游离细胞尿液 DNA 或通过细胞分选和微流控技术来增加突变等位基因的百分比的尝试都没有成功或仍未得到证实。然而，细胞学检查可以立即启用 NGS：具有足够比例异常细胞的尿液细胞学可以直接进行 NGS 检测，对 UC 检测具有高灵敏度。对于异常细胞比例较低的病例，对 NGS 进行细胞学靶向微切割应该可以保持灵敏度并降低测序成本。对 NGS 进行细胞学靶向尿路上皮细胞可以作为低级别 UC 的筛查试验。
细胞学立即为 NGS 改善 UC 诊断提供了条件，允许 NGS 作为非典型细胞学的辅助检测，并且有可能允许低级别 UC 的筛查试验。
