The detection of FH deficiency by immunohistochemistry in a significant proportion of tumors histologically diagnosed as “unclassified RCC” or “papillary RCC type 2” demonstrates the need to establish immunohistochemistry‐based screening strategies for these tumors (Chen et al., 2014; Gupta et al., 2019; Trpkov et al., 2016). The gene discussed is FH; the disease is renal cell carcinoma.