MAPK1 and neoplasm: In an attempt to understand the mechanistic background of cancer on a molecular basis, scientific investigations in the recent decades have led to the discovery of the causal relationship between the pathologically hyperactivated RAS-RAF-MEK-ERK signaling cascade – a mitogen-activated protein kinase (MAPK) pathway – and development and progression of various leading tumor entities, including non-small cell lung cancer (NSCLC), colorectal carcinoma (CRC), pancreatic ductal adenocarcinoma (PDAC), and malignant melanoma (3).