However, temporary knockdown of p53 during 1.8 Gy × 4 TBI significantly suppressed lymphoma formation in both KrasLA1; CMV-rtTA; TRE-p53.1224 and KrasLA1; Actin-rtTA; TRE-p53.1224 mice (referred to as KrasLA1; shp53 mice hereafter) compared with littermate controls (Fig. 4b,c). The gene discussed is TP53; the disease is lymphoma.