CDKN2A and lymphoma: When tumors developed in the offspring, we harvested lymphoma from λ-Myc;CreER;Chek1Flox/D130A;Cdkn2a+/−, λ-Myc;CreER;Chek1Flox/Flox;Cdkn2a+/− or λ-Myc;CreER;Chek1Flox/wt;Cdkn2a+/− mice.