CREBBP and small cell lung carcinoma: The dose–response curves for Volasertib revealed IC50 values significantly higher for the non-mutated SCLC cell lines NCI-H841, NCI-H889, NCI-H2171 and NCI-H146 than for the CREBBP mutated SCLC cell lines NCI-H1048, NCI-H1963, NCI-H211 and HCC33 (13.3 vs. 3.7 nM, respectively; p = 1.35 × 10−12) (Figure 3A).