In the group of CML preceding Ph-negative MPN, CALR mutation and BCR::ABL1 rearrangement were identified simultaneously at CML diagnosis in 10/10 cases, in which CALR was evaluated at initial CML diagnosis (Cabagnols et al., 2015; Loghavi et al., 2015; Diamond et al., 2016; Dogliotti et al., 2017; Gilles et al., 2017; Blouet et al., 2018; Lewandowski et al., 2018; Balducci et al., 2020; Yoon et al., 2020; Huo et al., 2023). The gene discussed is BCR; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.