Objective         To determine the expression changes of large conductance calcium-activated potassium (BK

Ca

) channel β2- (KCNMB2) and β4-subunits (KCNMB4) in human astrocytic tumors of different WHO grades

and to investigate the molecular mechanism of astrocytic tumor proliferation and growth.         Methods         Eighty-four brain specimens were obtained

including 15 normal brain specimens and 69 astrocytoma specimens with different WHO grades. Expression levels of KCNMB2 and KCNMB4 in these astrocytoma tissues were detected by immunohistochemical staining (IHC) and

Western blotting.         Results         Compared with normal brain tissues

KCNMB2 and KCNMB4 were up-regulated in the astrocytoma tissues (P0.05). The expression of KCNMB2 was correlated with WHO grade (P0.05) rather than gender

age and the site of tumor (P0.05). The stronger the expression of KCNMB2 was

the higher the tumor WHO grade was. The expression of KCNMB4 had no correlation with gender

age

WHO grade or the site of tumor (P0.05).         Conclusion         KCNMB2 and KCNMB4 are highly expressed in astrocytoma tissues

and the expression of the former is related to the WHO grades of astrocytic tumor.