While hematologic cancer cell lines were on average more sensitive to BRD-810 treatment than solid tumor cells, sensitivity to BRD-810 was observed across tumor indications and we propose the ratio of BCL2L1 to BAK mRNA as a potential biomarker for patient stratification in ongoing and future MCL1 inhibitor trials. The gene discussed is BAK1; the disease is hematopoietic and lymphoid cell neoplasm.