GFI1B and adenocarcinoma: Similar to our previous study [17], strong co-expression of POU2F3 and GFI1B, characteristic of non-neoplastic tuft cells, was the criterion to identify 1 (0.4%) tuft cell-like adenocarcinoma and 3 (1.7%) tuft cell-like SQCCs in the centrally reviewed “bona fide” cohorts of the TCGA adenocarcinoma and SQCC datasets [22, 23, 25, 26] (Fig. S7A).