SPHK1 and neoplasm: Given the demonstrated clinical safety and tolerability of safingol in combination with cisplatin, as well as the availability of several other SPHK1 and S1P inhibitors in stage clinical development, we suggest that combining such agents with cytotoxic chemotherapy or investigating their activity in patients who have developed secondary resistance to chemotherapy is a promising clinical strategy and that a high tumour SPHK1:SGPL1 ratio could provide a predictive biomarker to select patients for this therapeutic approach.