Interestingly, in addition to promoting tumour progression, other related studies have found that RIPK4 can also inhibit tumour progression; for example, RIPK4-mediated inhibition of STAT3 signalling slows the progression of lung cancer (Kopparam et al., 2017) and plays a role in inhibiting tumour progression in tongue squamous cell carcinoma and squamous cell carcinoma of the skin (Xinhua et al., 2014) (Chen et al., 2017). Here, RIPK4 is linked to skin squamous cell carcinoma.