LIF and head and neck squamous cell carcinoma: Several lines of evidence have indicated that LIF is secreted either by cancer cells and/or CAFs across diverse cancers.[30, 45, 51, 52] Indeed, a previous study from Yae Ohata's group has suggested that LIF protein is mainly produced by CAFs in oral SCC,[30] while Jean Albrengues reported that LIF protein was abundantly secreted by multiple carcinoma cells including oral SCC.[45] Our results reconciled with this discrepancy and revealed that both HNSCC cancer cells (especially those CSCs) and CAFs were able to produce and secrete LIF.