BHD-associated HOCT exhibited transcriptomic intratumor heterogeneity (tITH) comprised of L1CAM and FOXI1 expressing cells, suggesting the possibility that the origin cell of BHD-associated HOCT may have already been genetically altered before differentiating into these two transcriptomically distinct lineages. Here, FOXI1 is linked to Birt-Hogg-Dube syndrome.