SLFN11 and cancer: The cancer cell lines HCT-116, HCT-15, MDA-MB-231, and MCF7, hypermethylated at the SLFN11 CpG island, had minimal expression of the SLFN11 RNA transcript, as determined by quantitative reverse transcription-PCR (Figure 2B), and protein, as assessed by western blot (Figure 2B) and immunofluorescence (Figure 2C).