For instance, as early as 2012, by investigating a plethora of lung cancer patient samples, Peifer and colleagues discovered that the genes CREBBP, EP300, and MLL, which are involved in the histone modification pathway, were mutated, thereby adversely affecting histone integrity, primarily in small-cell lung cancer (SCLC) with a poor prognosis. Here, KMT2A is linked to lung carcinoma.