GTF3C4 and breast cancer: Conversely, within the same cell lines there is a substantial decrease in the HATs GTF3C4 (H3K14ac), MYST1 (H4K16ac) and CDY1 (H4ac), and this is consistent with the observed decrease in H4 acetylation in the MCF7 and MDA-MB231 breast cancer cell lines (Figure 4).