Several false-positive PPARγ staining results led to a positivepredictive value of only 72%, but the overall negative predictive value offrozen section plus immunostaining at this institution was 99%, meaning thatfive additional cases of carcinoma in this series of 39 cancers could have beenidentified intraoperatively, reducing the need for completion thyroidectomy toa single patient (3%). The gene discussed is PPARG; the disease is cancer.