CD44 and chondrosarcoma: In particular, CD44 is the main receptor involved in cellular proliferation, differentiation, and migration pathways and consequently in tumor progression and metastasis; moreover, it is overexpressed in various types of tumors like melanoma, chondrosarcoma, breast, gastrointestinal, prostate, bladder, lung, and pancreatic cancers, and different studies have reported a relationship between CD44 expression and poor prognosis [77].