AXIN-1 protein expression and localization in glioblastoma.

The etiology and pathogenesis of tumors of the central nervous system are still inadequately explained. In the present study the expression patterns of a critical molecular component of wnt signaling pathway - axin I was investigated in 42 patients with glioblastoma, the most aggressive form of glial tumors. Immunostaining and image analysis revealed the quantity and localization of the protein. Downregulation of this tumor suppressor expression was observed in 31% of tumors when compared to the levels of axin in healthy brain tissues. Axin was observed in the cytoplasm in 69% of glioblastoma samples, in 21.4% in both the cytoplasm and nucleus and 9.5% had expression solely in the nucleus. Mean values of relative axin's expression obtained by image analysis showed that the highest relative quantity of axin was measured when the protein was in the nucleus and the lowest relative quantity of axin when the protein was localized in the cytoplasm. Investigation on axin's existence at the subcellular level in glioblastomas suggests that axin's expression and spatial regulation is a dynamic process. Despite increasing knowledge on glioma biology and genetics, the prognostic tools for glioblastoma still need improvement. Our findings on expression of axin 1 may contribute to better understanding of glioblastoma molecular profile.