The spectrum of MEK1 mRNA expression was dramatically variable, indicating that MEK1 harbored some distinct traits to be expressed widespread, such as diffuse large B cell lymphoma (DLBC), acute myeloid leukemia (LAML) and uterine carcinosarcoma (UCS); or to be expressed narrowly, such as KIRC, THCA and pancreatic carcinoma (PAAD). Here, MAP2K1 is linked to uterine carcinosarcoma.