Chronic lymphocytic leukemia: pathophysiology and current therapy.

Chronic lymphocytic leukemia (CLL) is the most frequent adult leukemia in western countries, but it is rare in Japan. Several mutations have been identified in patients with CLL using next-generation sequencing, but disease-specific mutations were not found. Some mutations, such as those in TP53, NOTCH1, SF3B, and BIRC3 are useful for risk stratification and prognosis prediction in patients with CLL. Strategies for treating CLL are rapidly evolving, with targeted agents such as the B-cell receptor signaling pathway inhibitors (ibrutinib, idelalisib), novel anti-CD20 monoclonal antibody (obinutuzumab), and Bcl-2 inhibitor (venetoclax) being approved by the US Food and Drug Administration. Although key drugs such as chlorambucil and rituximab cannot be used in Japan, others such as ibrutinib and bendamustine were recently approved for CLL treatment in Japan.