Across a panel of cancer cell lines, copy number generally did not correlate with ADC activity in vitro, a phenomenon observed for ADCs against other targets.16, 28 For example, KG1 cells were found to express the highest levels of SAIL yet were resistant to cell killing by the ADC, despite their sensitivity to free (unconjugated) monomethyl auristatin E (MMAE) (Figures 4 and 5f). This evidence concerns the gene C16orf54 and cancer.