ABSTRACT
In order to evaluate the predictive value of positron emission tomography-computed tomography (PET/CT) in discriminating the presence of a Richter's syndrome (RS) or a second malignancy (SM), as well as to evaluate its prognostic value in patients with chronic lymphocytic leukemia (CLL), we retrospectively analyzed the data of 90 patients who, in the suspicion of a RS or a SM, underwent PET/CT followed by the biopsy of the involved tissue. The median maximum Standardized Uptake Value (SUV max) in the presence of a CLL/small lymphocytic lymphoma, a diffuse large B-cell lymphoma (DLBCL), a Hodgkin lymphoma (HL), a SM were 3.5, 14.6, 7.0 and 6.3, respectively (P ⩽ 0.0001). A SUV max cutoff value ⩾ 5 showed a sensitivity, specificity, positive and negative predictive values of 88.2, 71.2, 51.3 and 94%, respectively, for the presence of a more aggressive disease (DLBCL, HL and SM). A SUV max ⩾ 5 identified also a subset of treatment naive patients with an inferior progression-free survival (P = 0.011) and overall survival (P = 0.067). These findings suggest that PET/CT may helpfully integrate the biologically-based prognostic stratification of CLL. Prospective clinical trials including larger cohorts of patients are needed to conclusively define the role and prognostic impact of PET/CT in the routine management of CLL patients.
Subject(s)
Hodgkin Disease/diagnosis , Leukemia, Lymphocytic, Chronic, B-Cell/diagnosis , Lymphoma, Large B-Cell, Diffuse/diagnosis , Neoplasms, Second Primary/diagnosis , Positron-Emission Tomography/methods , Tomography, X-Ray Computed/methods , Adult , Aged , Aged, 80 and over , Combined Modality Therapy , Female , Follow-Up Studies , Hodgkin Disease/mortality , Hodgkin Disease/therapy , Humans , Leukemia, Lymphocytic, Chronic, B-Cell/mortality , Leukemia, Lymphocytic, Chronic, B-Cell/therapy , Lymphoma, Large B-Cell, Diffuse/mortality , Lymphoma, Large B-Cell, Diffuse/therapy , Male , Middle Aged , Neoplasm Staging , Neoplasms, Second Primary/mortality , Neoplasms, Second Primary/therapy , Prognosis , Retrospective Studies , Survival RateABSTRACT
Deregulation of the miR-15a/16-1 cluster has a key role in the pathogenesis of chronic lymphocytic leukemia (CLL), a clinically heterogeneous disease with indolent and aggressive forms. The miR-15a/16-1 locus is located at 13q14, the most frequently deleted region in CLL. Starting from functional investigations of a rare SNP upstream the miR cluster, we identified a novel allele-specific mechanism that exploits a cryptic activator region to recruit the RNA polymerase III for miR-15a/16-1 transcription. This regulation of the miR-15a/16- locus is independent of the DLEU2 host gene, which is often transcribed monoallellically by RPII. We found that normally one allele of miR-15a/16-1 is transcribed by RNAPII, the other one by RNAPIII. In our subset of CLL patients harboring 13q14 deletions, exclusive RNA polymerase III (RPIII)-driven transcription of the miR-15a/16-1 was the consequence of loss of the RPII-regulated allele and correlated with high expression of the poor prognostic marker ZAP70 (P=0.019). Thus, our findings point to a novel biological process, characterized by double allele-specific transcriptional regulation of the miR-15a/16-1 locus by alternative mechanisms. Differential usage of these mechanisms may distinguish at onset aggressive from indolent forms of CLL. This provides a basis for the clinical heterogeneity of the CLL patients carrying 13q14 deletions.
