SPHK1 expression has been reported to be upregulated in head and neck squamous cell carcinoma (HNSCC)4, 15, 16 and SPHK1-deficient mice were resistant to 4-nitroquinoline-1-oxide (4-NQO)-induced carcinogenesis4. This evidence concerns the gene SPHK1 and head and neck squamous cell carcinoma.