In tumour-free tissues from otherwise healthy individuals undergoing nephrectomies for renal cell carcinoma, lumican-based proteoglycans were predominantly detected in the tubulointerstitium, deriving from peritubular mesenchymal cells, with a lower expression in the mesangial matrix of the glomerular compartments; in diabetic tissues, a marked increase in tubular expression was observed, which was not paralleled in glomeruli until advanced diabetic kidney disease was established [56, 57]. Here, LUM is linked to diabetic kidney disease.