PCDH11X and Nephroblastoma: In a search of the COSMIC database, none of the mutations were previously described in renal cell carcinoma (n = 6), and in a broader search of kidney cancer [carcinoma (n = 4512), leiomyoblastoma (n = 3), renal cell carcinoma (n = 6), Wilms tumor (n = 1354), not specified (n = 106), and other (n = 143)], only two mutations were reported with a frequency above 1%: COL14A1 (1%, n = 2168) and PCDH11X (2.4%, n = 2168).