Importantly, targeting the anti-apoptotic protein BCL-2 by the antagonistic agent venetoclax is effective in relapsed CLL patients, including those with negative prognostic features [143]; however, venetoclax resistance development can be observed in some cases, potentially mediated through the compensatory upregulation of other anti-apoptotic proteins from the BCL-2 family. The gene discussed is BCL2; the disease is B-cell chronic lymphocytic leukemia.