RNA methyltransferases such as METTL3, METTL14, WTAP, and VIR can catalyze the methylation of the N6 position of adenylate (M6A) and are opposed by demethylases which include FTO and ALKBH5.

The nucleosome consists of an octamer composed of four histones (H2A, H2B, H3, and H4) and a DNA entangled with 147 base pairs. The core of the histones constituting the nucleosome are roughly the same, but the free N-terminus can be subjected to various modifications.

The extracellular signal-regulated kinases, or ERK1/2 (MAPK1/MAPK3, p44/42MAPK), are signaling molecules belonging to the mitogen-activated protein kinase family (MAPKs) that are commonly located in the cytoplasm of eukaryotic cells. In concert with various other molecules in the signaling cascade acting under different surface or intracellular receptors, ERK1/2 act as catalysts in the phosphorylation of serine/threonine and are negatively regulated by the bispecific (Thr/Tyr) MAPK phosphatase family (called DUSP or MKP) and specific inhibitors to MEK activity (such as U0126 and PD98059).

DNA methyltransferase (DNMT) is an important family of enzymes that catalyze and maintain DNA methylation, a common marker in the epigenetic silencing of target genes. The enzymes play a key role in the regulation of gene expression and genomic imprinting/development.

Astrocytes are specialized glial cells with distinct morphology that are found in the central nervous system, playing a role in brain and nerve cell development and the formation of synapses. Mature astrocytes respond to many stress signals and are responsible for many essential complex functions in the healthy brain, allowing the maintenance of proper homeostasis through ion flow, signaling, and the recycling of neurotransmitters. Astrocytes that are irregularly activated may result in various neurological disorders, including Alzheimer's disease and Huntington's disease. 

Glial fibrillary acidic protein (GFAP) is an intermediate filament protein that is mainly found in astrocytes. It is also expressed in chondrocytes, fibroblasts, myoepithelial cells, lymphocytes, and hepatic stellate cells.

Epidermal growth factor receptor (EGFR, also known as ErbB-1 or HER1) is a member of the ErbB family. This family includes four tyrosine receptor kinases: HER1 (ErbB1, EGFR), HER2 (ErbB2, NEU), HER3 (ErbB3), and HER4 (ErbB4). The ErbB family plays an important regulatory role in the process of cell physiology, and is among the most studied receptor tyrosine kinases and signaling molecules in the history of biochemistry and cell biology.

EGFR is distributed along the surface of cells including mammalian epithelial cells, fibroblasts, glial cells, keratinocytes, and more. The EGFR signaling pathway plays an important role in physiological processes such as cell growth, proliferation and differentiation. Upon ligand binding (for example, EGF interacting with the extracellular domain of EGFR), the ErbB receptor tyrosine kinases will homodimerize or heterodimerize, allowing autophosphorylation of cytosolic tyrosine residues and the recruitment of downstream signaling molecules.

The loss of function in tyrosine kinases such as EGFR, or the abnormal activity/cell localization of key factors in related signaling pathways, such as the p38 MAPK pathway, can cause multiple cancer types, diabetes, immunodeficiency and cardiovascular diseases. In modern medicine, typical treatment strategies include targeting the tyrosine kinase activity of the ErbB receptor with small molecular inhibitors, or humanized antibodies that will target cells that have overexpressed the ErbB receptor, such as using an anti-HER2 therapy to treat breast cancer.