Clinical and Molecular Studies of Diffuse Large B-cell Lymphoma

The general aim of this thesis was to study the prognostic clinical and biological markers of Diffuse Large B-cell Lymphoma (DLBCL). Paper I: Utilizing population-based data for patients with DLBCL in Sweden, the study aimed to establish whether event free survival at 24 months (EFS24) was a reproducible milestone. The disease-free survival for lymphoma patients was compared with that of age and sex matched Swedish general population. We demonstrated that overall survival was similar to age and sex matched general population only for younger patients (<60 years of age) achieving ES24. Patients older than that had worse prognosis. Death was mainly linked to cardiovascular disease and secondary malignancies. Paper II: Plasma samples collected via the bio bank U-CAN were analyzed using multiplex extension assay (PEA) utilizing preselected protein panels to examine the possibility of distinguishing lymphomas, leukemias and controls. The study confirmed that PEA technology could be used not only to effectively screen for large number of plasma protein biomarkers in low plasma sample volumes (1 µL), but even to discriminate between controls and different haematological malignancies. Paper III: Plasma protein pattern evolution in DLBCL patients was highlighted by PEA analysis of plasma proteins at different time points under treatment with Rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP). Significant distinctions in protein patterns at diagnosis compared to controls and striking differences in protein levels before and after treatment in patient who responded to treatment were evident. The three top proteins were TCL1A, CXCL13 and IL2RA. Paper IV: An interesting protein that emerged from the above studies was TCL1A. This plasma protein was analyzed in plasma samples by PEA. Validation by plasma enzyme immunosorbent assay (ELISA) was attempted. The cytoplasm and nucleus bound form of TCL1A were analyzed with the help of immunohistochemistry in tissue microarray samples. The study included 178 patients of which 125 received R-CHOP. Clinical risk factor analysis showed no significant correlation with tissue IHC. Significantly higher levels of plasma TCL1A were seen in male patients (measured by ELISA and PEA) and in patients with Ann Arbor stages II-IV (measured by PEA). Survival analysis showed no statistical significance.