For example, in glycolytically-active HPV−ve HNSCC cells, lactate homoeostasis is likely to play a significant role in cell survival, a process requiring specialised monocarboxylic acid transporters: MCT1-4.29,30 Although these transporters facilitate metabolic shuttles, they were not included in the public global metabolism related gene list used for earlier comparison (Supplementary table 2) and we therefore directly examined the RNA sequencing data for expression of MCT1, MCT2 and MCT4 (MCT3 was not included due to its restricted expression to retina/choroid plexus epithelium). The gene discussed is SLC16A3; the disease is head and neck squamous cell carcinoma.