In addition to well‐known modulated genes in CLL B cells determined in 2D cell cultures, regulating, for example, the Notch pathway and the composition of the extracellular matrix,1, 2 our model identified differentially expressed genes regulating the AP‐1 complex in the core region, suggesting a previously unrecognized role of AP‐1 in CLL pathogenesis.52, 53. Here, FOS is linked to B-cell chronic lymphocytic leukemia.