KEY CLINICAL MESSAGE:Previous studies showed that DNAJB9 is protective against metastatic TNBC. Our patient had complete pathologic response of nonmetastatic TNBC after 3 cycles of chemotherapy but developed DNAJB9-related fibrillary glomerulonephritis. Was DNAJB9 pivotal for this remarkable TNBC response, and if so, could it be a potential biomarker or target looking forward?