ERBB2 and neoplasm: Furthermore, genomic peak coverage analysis showed that the decrease of H3K4me1 peak regions was corroborated by reduction of H3K4me1 genomic peak coverage in the KO tumours (10% for Neu vs 6% for KO), while the H3K4me1 mark remained essentially stable (1.8% for Neu vs 1.2% for KO).