MPO and cancer: We can perform laboratory examinations such as ANA, anti-dsDNA, ANCA, anti-MPO and anti-PR3 [35], cryoglobulins, C3 and C4, serum and urinary immunofixation, free light chains [36], anti-THSD7A, anti-PLA2R [37] to exclude autoimmune and immune-mediated diseases, cancer and other diseases leading to hypercoagulable state [38], so as to enhance the reliability of the diagnosis of NS.