Putting our findings in MCC in the broader context of studies investigating LSD1i treatment in other cancers, such as AMLs (Schenk et al, 2012; Somervaille et al, 2016; Fang et al, 2019; Cai et al, 2020), SCLC (Mohammad et al, 2015; Augert et al, 2019), prostate cancer (Sehrawat et al, 2018), and cutaneous squamous cell carcinoma (Egolf et al, 2019), it appears that in certain cellular lineages, the neuroendocrine lineage among them, LSD1 is a gate‐keeper of lineage plasticity. The gene discussed is KDM1A; the disease is cancer.