CD40, a member of the superfamily of tumor necrosis factor receptors involved in cell differentiation [25], has been proved to be an effective tumor marker in many tumors [26–28], especially in non-B-cell-derived solid tumors, such as nasopharyngeal carcinoma [29], normal bladder cancer [12], cervical cancer [30], and renal cancer [11]. Here, CD40 is linked to renal carcinoma.