Increased miR-155 expression in MBL, CLL, and CLL poor responders. Approximately 1% to 2% of patients with MBL will develop CLL; however, a direct correlation between MBL and CLL is controversial. Ferrajoli et al report that cellular miR-155 expression increased from B cells to MBL and CLL. Microvesicles secreted from both MBL and CLL also contained miR-155 in increasing amounts. Patients with lower cellular miR-155 expression responded to standard therapies better than those patients with high miR-155 levels. Professional illustration by Alice Y. Chen.