In a report using proteomics and immunohistochemistry, significant expressions of both EXT1/EXT2 were detected together on the GBM of PLA2R-negative secondary membranous nephropathy including MLN, whereas both EXT1/EXT2 were absent in all included cases of PLA2R-associated primary membranous nephropathy [22]. Here, PLA2R1 is linked to membranous glomerulonephritis.