背景:BCR:ABL1样或费城染色体样(Ph样)急性淋巴细胞白血病(ALL)于2009年首次报道。Ph样ALL的特征是类似于费城染色体ALL的基因签名,但没有BCR::ABL1融合。分子上,Ph-likeALL分为七类,CRLF2和ABL类重排是两种最常见的亚型,在不同的下游信号级联中表现出改变。
方法:我们报告了一例罕见的小儿Ph样ALL合并CRLF2和ABL1重排的病例。CRLF2与其最常见的融合伴侣P2RY8融合,而ABL1与MYO18B融合,一种以前没有报道过的新型融合伴侣。4岁女性患者使用国家多中心CCCG-ALL-2020方案进行治疗,当通过RNA-seq确认ABL1重排时,在诱导结束时添加达沙替尼。形态和分子,患者持续缓解直至最后一次随访.据我们所知,这是Ph-likeALL的第一个案例,拥有两个不同的重排类别。
结论:我们的结果确定ABL1重排和CRLF2重排可以共存。FISH的应用,全转录测序,PCR可以帮助我们对ALL细胞遗传学和分子生物学有更全面的了解。需要进一步的研究来探索靶向治疗在这种罕见的临床情况下的作用。
BACKGROUND: BCR::ABL1-like or Philadelphia chromosome-like (Ph-like) acute lymphoblastic leukemia (ALL) was first reported in 2009. Ph-like ALL is characterized by gene signature similar to Philadelphia chromosome ALL, but without BCR::ABL1 fusions. Molecularly, Ph-like ALL is divided into seven categories, with CRLF2 and ABL-class rearrangements being the two most common subtypes, exhibiting alterations in distinct downstream signaling cascades.
METHODS: We report a rare
case of pediatric Ph-like ALL with concomitant CRLF2 and ABL1 rearrangements. CRLF2 was fused with P2RY8, its most common fusion partner, whereas ABL1 was fused with MYO18B, a novel fusion partner that has not been previously reported. The 4-year-old female patient was treated using the national multicenter CCCG-ALL-2020 protocol with the addition of dasatinib at the end of induction when ABL1 rearrangement was confirmed by RNA-seq. Morphologically and molecularly, the patient remained in continuous remission until the last follow-up. To the best of our knowledge, this is the first
case of Ph-like ALL harboring two distinct rearrangement categories.
CONCLUSIONS: Our results identified that ABL1 rearrangement and CRLF2 rearrangement can coexist. The application of FISH, whole transcription sequencing, PCR can help us to have a more comprehensive understanding of ALL cytogenetics and molecular biology. Further studies are needed to explore the role of targeted therapies in such rare clinical scenarios.