Expression of heat shock proteins in brain tumors

Heat shock proteins (HSP) are an evolutionary conserved family of proteins that serve as molecular chaperones, preventing the formation of nonspecific protein aggregates and assisting proteins in the acquisition of their native structures. Furthermore, HSPs have anti-apoptotic properties and have been found to be elevated in many human cancers; their overexpression has been associated with poor survival and response to therapy. In the present study we assessed the HSP expression in brain tumors. Simultaneous detection of HSP27, HSP40, HSP60, HSP70, HSP90a, total Akt and phospho- Akt in 19 brain tumor specimens was performed using the multiplex bead array assay. There was expression of HSP27 (pSer82), HSP27 (pSer15), HSP40, HSP60, HSP70, HSP90a, total-Akt and phospho- Akt in both gliomas and meningiomas. Significantly higher levels of HSP70 and a trend towards higher levels of HSP40 were found in meningiomas compared to gliomas. There was a significant correlation between HSP27 (pSer82) and HSP27 (pSer15) expression and between HSP90a and both total-AKT and phospho- AKT. A significant correlation between HSP27 and total-AKT was observed. Since HSPss are an attractive target for anticancer therapy, further studies are needed in order to better assess their relationship with tumor aggressiveness and patient prognosis.