CD44 and cancer: CD44, along with epithelial growth factor receptor (EGFR), may regulate metastasis and cell signaling pathways, including the Ras-MAPK and PI3K/Akt pathways, which are implicated in the regulation of malignant phenotypes of cancer cells, characterized by cellular processes such as cell adhesion, migration, invasion, and epithelial-to-mesenchymal transition (EMT) (59) (Figure 2).