Phelps Rachel, Gallon Richard, Hayes Christine, Glover Eli, Gibson Philip, Edidi Ibrahim, Lee Tom, Mills Sarah, Shaw Adam, Heer Rakesh, Ralte Angela, McAnulty Ciaron, Santibanez-Koref Mauro, Burn John, Jackson Michael S
Biosciences Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.
Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.
Cancers (Basel). 2022 Aug 8;14(15):3838. doi: 10.3390/cancers14153838.
Identification of mismatch repair (MMR)-deficient colorectal cancers (CRCs) is recommended for Lynch syndrome (LS) screening, and supports targeting of immune checkpoint inhibitors. Microsatellite instability (MSI) analysis is commonly used to test for MMR deficiency. Testing biopsies prior to tumour resection can inform surgical and therapeutic decisions, but can be limited by DNA quantity. MSI analysis of voided urine could also provide much needed surveillance for genitourinary tract cancers in LS. Here, we reconfigure an existing molecular inversion probe-based MSI and BRAF c.1799T > A assay to a multiplex PCR (mPCR) format, and demonstrate that it can sample >140 unique molecules per marker from <1 ng of DNA and classify CRCs with 96−100% sensitivity and specificity. We also show that it can detect increased MSI within individual and composite CRC biopsies from LS patients, and within preoperative urine cell free DNA (cfDNA) from two LS patients, one with an upper tract urothelial cancer, the other an undiagnosed endometrial cancer. Approximately 60−70% of the urine cfDNAs were tumour-derived. Our results suggest that mPCR sequence-based analysis of MSI and mutation hotspots in CRC biopsies could facilitate presurgery decision making, and could enable postal-based screening for urinary tract and endometrial tumours in LS patients.
建议对林奇综合征（LS）进行筛查时鉴定错配修复（MMR）缺陷型结直肠癌（CRC），这有助于指导免疫检查点抑制剂的靶向治疗。微卫星不稳定性（MSI）分析常用于检测MMR缺陷。在肿瘤切除术前对活检组织进行检测可指导手术和治疗决策，但可能受DNA数量限制。对排出的尿液进行MSI分析也可为LS患者的泌尿生殖道癌症提供急需的监测。在此，我们将现有的基于分子倒置探针的MSI和BRAF c.1799T>A检测方法重新配置为多重PCR（mPCR）形式，并证明其能够从<1 ng DNA中对每个标记物的>140个独特分子进行采样，对CRC进行分类，灵敏度和特异性为96%-100%。我们还表明，它能够在LS患者的单个和复合CRC活检组织中，以及在两名LS患者的术前尿液游离DNA（cfDNA）中检测到MSI增加，其中一名患者患有上尿路尿路上皮癌，另一名患有未确诊的子宫内膜癌。大约60%-70%的尿液cfDNA来源于肿瘤。我们的结果表明，基于mPCR序列分析CRC活检组织中的MSI和突变热点可有助于术前决策，并能够对LS患者进行基于邮寄样本的尿路和子宫内膜肿瘤筛查。
