Department of Pediatrics, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Department of Pediatrics, Kochi Health Sciences Center, Kochi, Japan.
Cancer Sci. 2022 Jul;113(7):2472-2476. doi: 10.1111/cas.15380. Epub 2022 May 31.
Lineage switch is a rare event at leukemic relapse. While mostly known to occur in KMT2A-rearranged infant leukemia, the underlying mechanism is yet to be depicted. This case report describes a female infant who achieved remission of KMT2A-MLLT3-rearranged acute monocytic leukemia, but 6 months thereafter, relapsed as KMT2A-MLLT3-rearranged acute lymphocytic leukemia. Whole exome sequencing of the bone marrow obtained pre-post lineage switch revealed two somatic mutations of PAX5 in the relapse sample. These two PAX5 alterations were suggested to be loss of function, thus to have played the driver role in the lineage switch from acute monocytic leukemia to acute lymphocytic leukemia.
谱系转换是白血病复发的罕见事件。虽然这种现象主要发生在 KMT2A 重排的婴儿白血病中，但潜在的机制尚未被描述。本病例报告描述了一名女性婴儿，她患有 KMT2A-MLLT3 重排的急性单核细胞白血病，经治疗后获得缓解，但 6 个月后复发为 KMT2A-MLLT3 重排的急性淋巴细胞白血病。在谱系转换前后采集的骨髓进行全外显子测序，发现复发样本中有两个 PAX5 体细胞突变。这两个 PAX5 改变被认为是功能丧失，因此在急性单核细胞白血病向急性淋巴细胞白血病的谱系转换中起驱动作用。
