CD44 protein is a group of widely distributed proteins with molecular weight of (85 ~ 160) × 10kd is a multi molecular form of membrane integrin with high sugar content. The molecular weight of CD44 ranges from 85 to 250 KD. It mediates the interaction between cells and between cells and extracellular matrix. It is also a glycoprotein composed of extracellular, transmembrane and cytoplasmic parts. The sugar chain is chondroitin sulfate and heparan sulfate.