SOS1 and neoplasm: Consistent with our prior observations, quantitative analysis of H&E-stained sections of lungs extracted at different timepoints during tumor progression confirmed that tumor burden was significantly reduced in the lungs of SOS1/2KO/KRASG12D mice as compared to those of their SOS1/2WT/KRASG12D counterparts during the early stages of tumorigenesis (Fig. 1h, i).