Briefly, the most important events are related to HA/CD44 binding, which elicits the anti-apoptosis and chemoresistance of breast tumor cells via a mechanism involving protein kinase C (PKC) and the production of miR-21 [18]; RHAMM signals to kinases, calmodulin, and cytoskeletal proteins, which primarily modify adhesion and cell motility in response to HA binding [19]; HARE binds to HA as well as to other GAGs, triggering extracellular signal-regulated kinases 1/2 (ERK1/2) and NF-kB activation, with an important role in the formation of lymph node metastasis in prostate cancer [20,21,22,23]. The gene discussed is MAPK3; the disease is prostate carcinoma.