With the continuous development of the cancer stem cell theory,biomarkers for CSCs (Cancer stem cells) have gradually become the hot issues in tumor research.As the most commonly used CSCs biomarker,CD44 gains lots of attentions.This paper will review recent research about CD44 molecule and its powerful role in regulating tumor progenesis and progression.

BACKGROUND:It is confirmed that the absence of hypoxia-inducible factor-1α (HIF-1α) accelerates the degenerative process in the intervertebral discs, and microRNAs have an important role in degeneration of the intervertebral discs.
OBJECTIVE:To evaluate the changes of microRNAs in the intervertebral discs of HIF-1α-deficient (HIF-1α-/-) mice which may mediate the signaling pathway of HIF-1α in the intervertebral discs.
METHODS: As previously reported, HIF-1α-/- mice were established. HIF-1α-/- mice and HIF-1αflox/flox mice (control mice) aged 4 weeks were used. MRI and histological staining were used to evaluate the degeneration of the intervertebral discs. Total RNAs were extracted from the intervertebral discs tissues by Trizol, and the differential expression profile of microRNAs was harvested by significance analysis of microarrays and Cluster, based on microarray screening. Real-time quantitative reverse transcription-PCR was applied to verify the reliability of microRNA array results.
RESULTS AND CONCLUSION:The number of nucleus pulposus cels in the intervertebral discs of HIF-1α-/- mice was decreased, the cels presented with smal size and the color deepened in the cytoplasm. Finaly, differential expression profile of microRNAs (n=10) was obtained, seven of which were upregulated and three were downregulated. In conclusion, the loss of HIF-1α may cause the imbalance of some important miRNAs, which may result in a large amount of dead nuclear pulposus cels and mediate disc degeneration in HIF-1α-/- mice.