Protein arginine methyltransferase 1 (PRMT1) is a major type I arginine methyltransferase that catalyzes the formation of monomethyl and asymmetric dimethylarginine. It was first identified to asymmetrically methylate histone H4 at the third arginine residue, forming the H4R3me2a histone mark. H4R3me2a is an active mark associated with the active regions of the genome. H4R3me2a stimulates the activity of lysine acetyltransferases such as CBP/p300, which catalyzes the acetylation of H3K27, a mark of active enhancers, super-enhancers, and promoters. There are a few studies on the genomic location of H4R3me2a, but none in human cells. In this study, we analyzed chromatin immunoprecipitation sequencing data to understand the genomic location of H4R3me2a in the human breast cancer cell line MCF7. Consistent with previous findings in avian cells, MCF7 H4R3me2a is present in intronic and intergenic regions. Nucleosomes with H4R3me2a and H3K27ac are next to nucleosome-free regions at super-enhancers, enhancers, and promoter regions of expressed genes. Genes critical for breast cancer have broad domains of nucleosomes with H4R3me2a, H3K27ac, and H3K4me3. With known interactions between PRMT1 and CBP/p300, we found a strong correlation between H4R3me2a and H3K27ac in MCF7 cells. The correlation studies were extended to confirm the co-existence of H4R3me2a and H3K27ac in the same mononucleosome of leukemic cells (K562 and MOLM-13). This study also demonstrates the coexistence of H4R3me2a with other enhancer marks, including H2BK12ac, H4K5ac, and H4K8ac, suggesting a synergistic role in transcriptional regulation. The study also characterizes the rate of removal of H4R3me2a compared to other methylation marks using a global methyltransferase inhibitor called Adenosine dialdehyde (AdOX). H3K4me3 is removed faster, with their levels declining in 13 hours, while H3K36me3 and H4R3me2a showed a difference in 48 hours. Other methylation marks like H3K27me3, H3K9me2, and H3K9me3 showed no difference with AdOX treatment within the tested timeframe (13-48 hours). This study provides a foundation for understanding the genomic landscape of H4R3me2a in human cells for the first time. It establishes the possible association between the writers and their respective histone marks. AdOX-based studies in leukemic cells provide a framework for understanding the dynamics of histone methylation marks, thereby aiding in developing better therapeutic strategies.