CEACAM5 and neoplasm: After 48 h, NILK-2301 induced dose-dependent killing of all CEACAM5-positive cell lines regardless of tumor type (Fig. 1) as determined by LDH release, with half maximum effective concentrations (EC50) ranging from 0.008 nM (H2122) to 0.15 nM (H508) (Table 1).