PDF(Pubmed)
Abstract：
Activation-induced cytidine deaminase (AID) is a B cell-specific mutator required for antibody diversification. However, it is also implicated in the etiology of several B cell malignancies. Evaluating the AID-induced mutation load in patients at-risk for certain blood cancers is critical in assessing disease severity and treatment options. We have developed a digital PCR (dPCR) assay that allows us to quantify mutations resulting from AID modification or DNA double-strand break (DSB) formation and repair at sites known to be prone to DSBs. Implementation of this assay shows that increased AID levels in immature B cells increase genome instability at loci linked to chromosomal translocation formation. This includes the CRLF2 locus that is often involved in translocations associated with a subtype of acute lymphoblastic leukemia (ALL) that disproportionately affects Hispanics, particularly those with Latin American ancestry. Using dPCR, we characterize the CRLF2 locus in B cell-derived genomic DNA from both Hispanic ALL patients and healthy Hispanic donors and found increased mutations in both, suggesting that vulnerability to DNA damage at CRLF2 may be driving this health disparity. Our ability to detect and quantify these mutations will potentiate future risk identification, early detection of cancers, and reduction of associated cancer health disparities.
摘要：
活化诱导的胞苷脱氨酶（AID）是抗体多样化所需的B细胞特异性突变体。然而,它还与几种B细胞恶性肿瘤的病因有关。在有某些血癌风险的患者中评估AID诱导的突变负荷对于评估疾病严重程度和治疗选择至关重要。我们已经开发了一种数字PCR（dPCR）测定法，该测定法使我们能够定量由AID修饰或DNA双链断裂（DSB）形成引起的突变，并在已知易于发生DSB的位点进行修复。该测定的实施表明未成熟B细胞中AID水平的增加增加了与染色体易位形成相关的基因座处的基因组不稳定性。这包括通常参与易位的CRLF2基因座，该易位与急性淋巴细胞白血病（ALL）亚型相关，该亚型不成比例地影响西班牙裔，尤其是那些有拉丁美洲血统的人。使用dPCR，我们在来自西班牙裔ALL患者和健康西班牙裔供体的B细胞来源的基因组DNA中表征了CRLF2基因座，并发现两者的突变增加。这表明CRLF2对DNA损伤的脆弱性可能会导致这种健康差异。我们检测和量化这些突变的能力将加强未来的风险识别，早期发现癌症，和减少相关的癌症健康差距。
