CD44 and neoplasm: In this section we compile what is known on the CD44 isoforms/exons expression profile from tumor samples and cell lines of clinically relevant cancers, as well as conduct an independent analysis using The Cancer Genome Atlas (TCGA) RNA sequencing (RNA-seq) data on CD44 splice isoforms derived from the GEPIA2 database (Figure 2; Tang et al., 2019).