MPO and lung carcinoma: Twenty-two malignancies were observed in 20 patients (20/240, 8.3%; 11 c-ANCA/PR3 ( +), 3 in p-ANCA/MPO ( +), and 2 in ANCA negative patients), which were 3 carcinomas of the lung, 7 genitourinary tract, 5 hematological system, 3 thyroid papillary, 2 breast, 1 sarcoma and 1 oral cavity.