Alternatively, IHC staining for CK14, observed only in one of the group 1 samples, was one of the characteristics of the ‘squamous cell carcinoma-like’ subtype [33]; therefore, CK14 immunostaining could be used for subclassifying group 1 tumors, even though it was rarely positive in non-muscle-invasive papillary high-grade UTUC. Here, KRT14 is linked to squamous cell carcinoma.