Notably, we found that the ductal cell markers and epithelial cell-specific markers reported previously, such as EPCAM, KRT18, SOX9, KRT19, MUC1, and FXYD3 (Peng et al., 2019; Moncada et al., 2020; Chen et al., 2021), were commonly expressed in the majority of clusters except for cluster 17, confirming tumor cell identity. This evidence concerns the gene KRT18 and neoplasm.