Assessment of clonal relationship of CLL and B-ALL. (A) NGS-based clonality assessment of immunoglobulin rearrangements in CLL (dark blue) and ALL (yellow) samples from each patient. Samples were analyzed for IGH (IGHV-IGHD-IGHJ and IGHD-IGHJ) and IGK gene rearrangements. Clonal rearrangements with an abundance >5% are shown. Productive rearrangements are depicted in dark blue (CLL) and yellow (ALL). Clonotypes of productive IGH rearrangements are indicated. In patient 2, ALL and CLL share the same productive IGH rearrangement. (B) Patient 2: the nucleotide and amino acid sequence of the CDR3 gene fragment of the abundant clonotype is shown. (C) Patient 2: NGS assessment was performed at the time of CLL and ALL diagnosis by using the QIAGEN myeloid panel, which encompasses 141 cancer-related genes. Alterations in cancer-related genes are shown in blue, and variants of unknown significance are shown in yellow. (D) Patient 2: dynamics of variant allele frequencies of cancer-related genes show persistence of a BIRC3-mutated clone, but the NOTCH1 mutation present in the CLL population is not detected in the ALL sample. IKZF1 and DNMT3A mutations occur in the ALL sample and are not present in CLL.