We found that isolated fPTC and sPTC nuclei were HER2− according to the Wolff criteria (originally developed for breast cancer formalin-fixed paraffin-embedded (FFPE) examination) [16], although a number of cases showed scattered HER2+ cells, ranging from 1.4% to 9% in fPTC and from 1% to 2.4% in sPTC (Figure 1A,B). The gene discussed is ERBB2; the disease is breast cancer.