MAPK1 and neoplasm: To assess the sensitivity of the switching dynamics measurement with regard to the detection of subtle chemical changes in a protein, we investigated two post-translational modifications: the glycosylation of the β-subunit of human chorionic gonadotropin (hCGβ), a hormone produced during pregnancy, which is also associated with some forms of tumours, and the phosphorylation of the extracellular signal-regulated protein kinase ERK2 (MAPK1), which is—among many biochemical processes—for instance, involved in transcriptional regulation.