RRBP1 and Birt-Hogg-Dube syndrome: ,42 Our single-cell transcriptomic analysis of BHD-associated HOCT tumours revealed that expressions of Notch genes as well as those of Notch downstream genes including HES and HEY family members were increased in the cluster of L1CAM expressing cells, suggesting that Notch signalling may associate with transcriptomic intratumour heterogeneity (tITH) of BHD-associated renal tumours.