Figure 4. Immunolocalization of proliferating cell nuclear antigen (PCNA) in the renal cortex from a patient with focal segmental glomerulosclerosis using an anti-PCNA antibody. Note the presence of more than 2 PCNA-positive cells per glomerulus and tubulointerstitial area, while the control shows less than 1 PCNA-positive cell per glomerulus or tubulointerstitial area (original magnification: 250X).