CD44 is highly expressed in stem/progenitor cells originating the intervertebral discs in the human notochord.

Objective: The notochord acts as a patterning structure, playing a key role in the formation of the vertebral column, both indirectly by inducing sclerotome cell differentiation and directly by forming the nucleus pulposus of intervertebral discs. The abnormal development of the notochord results in an easy equation with a variety of birth defects. Therefore, we focused our attention on the analysis of the early stages of human notochord development by highlighting the role of progenitor stem cells involved in the origin of intervertebral discs (IVDs).