P4HA1 and squamous cell carcinoma: Its mRNA expression is also reported to associate with poor survival in breast cancer (Gilkes et al., 2013b) and squamous cell carcinoma (Kappler et al., 2017; Tawk et al., 2016), and the P4HA1 protein expression correlates with poor prognosis in high‐grade gliomas (Hu et al., 2017).