LEF1 and B-cell chronic lymphocytic leukemia: NWs with controlled geometry have achieved high siRNA transfection efficiency (>95%) for different types of primary immune cells, including adherent (DC, macrophage, NK) and nonadherent (T and B, Figure6a,b) immune cells, with minimal immune response activation.[28] For instance, SiNW‐facilitated transfection of siRNAs that silence the expression of LEF1 gene—a terminal transcriptional activator and a canonical target of the Wnt signaling pathway—severely impaired the survival of human B cells obtained from a chronic lymphocytic leukemia (CLL) patient (Figure 6c, right).