WT1 and nonpapillary renal cell carcinoma: WT1 had also been investigated, but appeared to be less sensitive and somewhat less specific than the three previously mentioned positive markers, seeing as WT1 reactivity was seen in 93% of the epithelioid mesotheliomas evaluated, but also in a single case of ccRCC that had metastasized to the lung (out of 40 evaluated) [55].