Springer, International Journal of Hematology, 4(102), p. 441-450
DOI: 10.1007/s12185-015-1847-4
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The transcription factor PU.1 and its inhibitory microRNA-155 (miR-155) are important regulators of B-cell differentiation. PU.1 downregulation coupled with oncogenic miR-155 upregulation has been reported in lymphoid malignancies; however, these data have not been studied across different subtypes in relation to clinical outcomes. We studied expression of miR-155 and PU.1 in the six most prevalent human B-cell lymphomas (n = 131) including aggressive (DLBCL, HL, MCL) and indolent (B-CLL/SLL, MZL, FL) types. Levels of miR-155 and PU.1 inversely correlated in DLBCL, B-CLL/SLL, and FL tumor tissues. In HL tissues, an exceptionally high level of miR-155 was found in patients with unfavorable responses to first-line therapy and those who had shorter survival times. PU.1 downregulation was noted in B-CLL/SLL samples positive for the adverse prognostic markers CD38 and ZAP-70. Upregulation of miR-155 and downregulation of PU.1 expression are integral aspects of lymphoma biology that could mark aggressive behavior of some, but not all, lymphoma types.