ACTG1 and hematopoietic and lymphoid cell neoplasm: From Figure 3a it is evident that, with the exception of a single case with an ACTB mutation in B-lymphoblastic leukemia/lymphoma, all hematological cancer cases that have somatic mutations in the cytoplasmic actin genes, i.e., 40 with ACTB and 18 with ACTG1 mutations, are patients with mature B-cell neoplasms.