Consistent with prior results reporting the high selectivity of simurosertib for CDC7,14 we observed significant correlations of simurosertib in vitro sensitivity with CDC7 mRNA (p = −0.612, p = 0.035) and protein (p = −0.806, p = 0.002) levels (Supplementary Fig. s3a), as well as loss of simurosertib sensitivity upon CDC7 KO in SCLC cell lines Supplementary Fig. 3b and c). Here, CDC7 is linked to small cell lung carcinoma.