PRRX1 and neoplasm: We used 5 different Cre strains to generate tumor study cohorts: Col1a2-Cre (Cre+n = 16, Cre-n = 6), Dermo1-Cre (Cre+n = 25, Cre-n = 18), P0-Cre (Cre+n = 20, Cre-n = 15), Prx1-Cre (Cre+n = 25, Cre-n = 24), and Sox9-Cre (Cre+n = 21, Cre-n = 15).