SLC8A2 and central nervous system cancer: They found that although the CpG island in the 5′ promoter region of SLC8A2 was unmethylated, the 5′ CpG-rich area (the so-called CpG island shore) was methylated, as were the CpG sites of three gene-body CpG islands located in exon 2, introns 2 and 3, and exon 3, in all eight glioma samples and three established glioma cell lines tested [20].