gms | German Medical Science

Objective: Tumor stem cells (CSCs) are considered tumor inducing. However, they also suggest that they play an essential role in chemoresistance, malignancy and recurrence. The clear identification of the CSCs is difficult and done mostly via specific marker proteins. One of these is CD44. This surface molecule acts as an interaction partner for various macromolecules of the extracellular matrix (ECM). By alternative splicing exist besides a stable form of CD44 (CD44s) also 10 variable (CD44v1-v10) via which these have a variety of tumor cell properties control (proliferation, adhesion, migration, invasion). The aim of this study was to investigate which of the CD44 isoforms are specifically expressed in human meningiomas and which of them increase with rising WHO grade.

Methods: RNA were isolated from 78 specimens of individual patients (WHO °I: n=43, WHO °II: n=32, WHO °III: n=3) and analysed by quantitative polymerase chain reaction (qPCR). The transcription of the stable form of CD44 (CD44s) as well as the variable isoforms CD44v1 until CD44v10 were analysed using delta Ct method to determine the expression level.

Results: It was found that there were strong variations in the detectability of the expression of the individual isoforms in human meningiomas. The only isoform that could be detected in all samples was CD44v6, whereas CD44v1 could not be detected in any of the samples tested. All other isoforms were detectable in least 35% of samples. The analysis of the expression levels of the isoforms CD44v6 and CD44v4 showed an increase with increasing WHO grade. For the isoforms CD44s and CD44v10 a decrease in expression levels was detected.

Conclusion: The data show that the CD44s and CD44v10 expression described for tumor progression in malignant tumor entities is detectable in low-grade meningiomas. However, for the malignant course additionally an increased expression of CD44v6 and CD44v4 seems to be specific for high grade tumors.