The identification of somaticRB1variation is crucial to confirm the heritability of retinoblastoma. We and others have previously shown that, when tumour DNA is unavailable, cell-free DNA (cfDNA) derived from aqueous humour (AH) can be used to identify somaticRB1pathogenic variation. Here we reportRB1pathogenic variant detection, as well as cfDNA concentration in an extended cohort of 75 AH samples from 68 patients. We show cfDNA concentration is highly variable and significantly correlated with the collection point of the AH. Cell-free DNA concentrations above 5 pg/µL enabled the detection of 93% of known or expectedRB1pathogenic variants. In AH samples collected during intravitreal chemotherapy treatment (Tx), the yield of cfDNA above 5 pg/µL and subsequent variant detection was low (≤46%). However, AH collected by an anterior chamber tap after one to three cycles of primary chemotherapy (Dx1+) enabled the detection of 75% of expected pathogenic variants. Further limiting our analysis to Dx1+ samples taken after ≤2 cycles (Dx ≤ 2) provided measurable levels of cfDNA in all cases, and a subsequent variant detection rate of 95%. Early AH sampling is therefore likely to be important in maximising cfDNA concentration and the subsequent detection of somaticRB1pathogenic variants in retinoblastoma patients undergoing conservative treatment.
体细胞RB1变异的鉴定对于确认视网膜母细胞瘤的遗传性至关重要。我们及先前研究已表明，在无法获取肿瘤DNA的情况下，源自房水（AH）的游离DNA（cfDNA）可用于识别体细胞RB1致病性变异。本研究报道了在68名患者的75份AH样本扩展队列中RB1致病性变异检测及cfDNA浓度分析结果。数据显示cfDNA浓度存在高度变异性，且与AH采集时间点显著相关。当cfDNA浓度高于5 pg/µL时，可检测到93%已知或预期的RB1致病性变异。在玻璃体内化疗期间（Tx）采集的AH样本中，cfDNA浓度超过5 pg/µL的比例及后续变异检出率较低（≤46%）。然而，在完成1-3个周期初级化疗后通过前房穿刺采集的AH样本（Dx1+）可实现75%预期致病性变异检出率。进一步将分析限定于≤2个化疗周期后采集的Dx1+样本（Dx≤2），所有病例均检测到可量化cfDNA水平，变异检出率达95%。因此，在接受保守治疗的视网膜母细胞瘤患者中，早期AH采样对于最大化cfDNA浓度及后续体细胞RB1致病性变异检测具有重要意义。
Genetic Diagnosis of Retinoblastoma Using Aqueous Humour—Findings from an Extended Cohort
肿瘤(癌症)患者之家