NOTCH1 and focal segmental glomerulosclerosis: To assess the expression of components of the Notch signaling pathway in healthy and pathologic kidneys, we performed immunofluorescence for Notch1, Notch2, and Notch3 in normal human kidneys or in kidney biopsies from patients affected by different types of glomerular disorders characterized by severe podocyte injury, such as LES nephritis and FSGS (Fig. 5).