RNA-Seq of B-lymphoid cancer cell lines and primary B-ALL patient samples revealed heterogeneous FBXW7 α and β isoform ratios. (A) FBXW7 AFE usage in B-lymphoid cancer cell lines from the CCLE RNA-Seq repository. Junctions per million (JPMs) were obtained by dividing each junction by the total sum of junctions multiplied by 1 million. Junctions are only counted if at least 5 unique spanning reads are observed. The y-axis shows the JPM fractions for each cell line, which approximates percent-spliced-in (PSI). Nalm6 and REH B-ALL cell lines are highlighted. BCL, B-cell lymphoma unspecified; Burkitt’s, Burkitt’s lymphoma; CLL, chronic lymphocytic leukemia-small lymphocytic lymphoma; DLBCL, diffuse large B-cell lymphoma; HL, Hodgkin lymphoma; LCAL, large cell anaplastic lymphoma; MCL, mantle cell lymphoma; MM, multiple myeloma (plasma cell myeloma). (B) FBXW7 AFE usage and transcript expression in patients with B-ALL at the CHOP (n = 18) and normal BM donors (n = 4). Each bar represents 1 sample. Plotted on the y-axis here and in the next panel are PSI values. (C) FBXW7 AFE usage and transcript expression in various B-ALL patient subtypes at St. Jude Children’s Hospital (n = 247). (D) Spearman correlation of β exon usage and overall FBXW7 transcript expression in patients with B-ALL at St. Jude Children’s Hospital.