CXCL13 and hereditary clear cell renal cell carcinoma: In recent years, several studies have reported the involvement of CXCL13 in the progression, metastasis, and prognosis of solid tumors,10 including breast cancer,11 colon cancer,12 prostate cancer,13 renal cell carcinoma,14 penile cancer,15 gastric cancer,16 etc. Compared with breast cancer tissues, CXCL13 is expressed at a low level in normal breast or adjacent noncancerous tissues.17,18 Notably, conflicting opinions have been raised regarding the role of CXCL13 in breast cancer.