Medical Genetics Division, Shizuoka Cancer Center Research Institute, Sunto-gun, Shizuoka, 411-8777, Japan.
Division of Pathology, Shizuoka Cancer Center Research Institute, Sunto-gun, Shizuoka, 411-8777, Japan.
Sci Rep. 2022 Feb 22;12(1):2953. doi: 10.1038/s41598-022-06885-2.
Targeted sequencing offers an opportunity to select specific drugs for cancer patients based on alterations in their genome. However, accurate sequencing cannot be performed in cancers harboring diffuse tumor cells because of low tumor content. We performed tumor cell enrichment using tissue suspension of formalin-fixed, paraffin-embedded (FFPE) tissue sections with low tumor cell content. The enriched fractions were used to efficiently identify mutations by sequencing a target panel of cancer-related genes. Tumor-enriched and residual fractions were isolated from FFPE tissue sections of intestinal and diffuse gastric cancers harboring diffuse tumor cells and DNA of suitable quality was isolated for next-generation sequencing. Sequencing of a target panel of cancer-related genes using the tumor-enriched fraction increased the number of detectable mutations and variant allele frequency. Furthermore, mutation analysis of DNA isolated from tumor-enriched and residual fractions allowed us to estimate germline mutations without a blood reference. This approach of tumor cell enrichment will not only enhance the success rate of target panel sequencing, but can also improve the accuracy of detection of somatic mutations in archived specimens.
靶向测序为癌症患者提供了根据基因组改变选择特定药物的机会。然而，由于肿瘤含量低，在弥漫性肿瘤细胞存在的癌症中无法进行准确的测序。我们使用含有低肿瘤细胞含量的福尔马林固定石蜡包埋（FFPE）组织切片的组织悬浮液进行肿瘤细胞富集。通过对癌症相关基因的目标面板进行测序，富集的部分可有效识别突变。从含有弥漫性肿瘤细胞的肠和弥漫性胃癌的 FFPE 组织切片中分离出富集的和残留的部分，并分离出适合下一代测序的 DNA。使用肿瘤富集部分对癌症相关基因的目标面板进行测序增加了可检测突变的数量和变异等位基因频率。此外，从肿瘤富集和残留部分分离的 DNA 的突变分析使我们能够在没有血液参考的情况下估计种系突变。这种肿瘤细胞富集的方法不仅可以提高目标面板测序的成功率，还可以提高对存档标本中体细胞突变的检测准确性。
