CYP27A1 and astrocytoma (excluding glioblastoma): Interestingly enough, BmKCTa and GaTx1, as well as CTX, have been tested on ion channels other than chloride and have been shown to possess no functional activity on these ion channels except on chloride.29 This therefore leads to the conclusion that CTX and CTX-like peptides bind with high specificity only to MMP-2 of human astrocytoma cells, including STTG1 cells under non-physiological conditions, thus making them highly specific targets of MMP-2 during non-physiological states and good candidates for diagnostic tools.