This is in line with the analysis of breast cancer cell lines in Cancer Cell Line Encyclopedia data, which highlights a role for both MCL1 and BCL2L1 (BCL-XL) in maintenance of breast cancer cell line viability in 2-D culture, whereas BCL2 appears largely non-essential in this context (Figure 2) [123,125,126]. This evidence concerns the gene BCL2L1 and breast cancer.