Expression of the promyelocytic leukemia zinc-finger in T-lymphoblastic lymphoma and leukemia has strong implications for their cellular origin and greater association with initial bone marrow involvement.

The promyelocytic leukemia zinc-finger (PLZF) is essential for the development of innate T cells (as represented by natural killer T cells) for acquisition of their unique innate immune properties. We evaluated the PLZF protein expression in a variety of immature and mature lymphoid malignancies. PLZF was preferentially expressed in T-lymphoblastic lymphoma/acute lymphoblastic leukemia (T-LBL/ALL) in 50% of the 54 cases. Among 51 cases of peripheral T-cell lymphoma not otherwise specified, only one (2%) expressed PLZF. One mycosis fungoides case expressed PLZF in lymph node involved by tumor. Otherwise, PLZF was not detected in any other type of lymphoma. In T-LBL/ALL, PLZF expression was more common in CD4/CD8 double-negative (67%) or CD8 single-positive subtypes (73%) than in CD4/CD8 double-positive (13%) and CD4 single-positive subtypes (0%) (P=0.001). Importantly, PLZF and CD1a expression were mutually exclusive in T-LBL/ALL (P=0.001). This was also the case for T-cell receptor ßF1 expression (P=0.000). Most (96%) of the PLZF-positive T-LBL/ALL cases showed initial bone marrow involvement compared with 39% of PLZF-negative cases (P=0.000). Based on these findings, we suggest that T-LBL/ALLs that express PLZF arise from early immature double-negative thymocytes when the T-cell receptor ß chain has not yet expressed or innate T-cell precursors, and strongly imply bone marrow involvement.

Clinical features and treatment outcomes of angioimmunoblastic T-cell lymphoma.

The objective of this retrospective study was to investigate clinical features and treatment outcomes in patients with angioimmunoblastic T-cell lymphoma (AITL), data of which were collected over a 15-year period. Sixty-five patients diagnosed with AITL were included in the study. About half of the patients (46.2%) presented with poor performance status (ECOG > or = 2); 72.3% of patients belonged to high intermediate or high-risk of IPI and same proportion belonged to Class 2 of PIT (Prognostic index for PTCL-U), and most patients (95.4%) were diagnosed at an advanced stage. At diagnosis, 27 patients (41.5%) presented with malignant pleural effusion, and 22 patients (33.8%) had skin involvement. Most of the initial chemotherapy regimens were anthracycline-based (88.2%). Overall response rate to initial chemotherapy was 86.2% (64.7% of complete response, 21.5% of partial response). The median progression-free survival and overall survival of all patients was 7.1 months (95% CI, 2.8 - 11.4) and 15.1 months (95% CI, 6.7 - 23.5), respectively. Age, performance status, and PIT scores were predictive prognostic factors for survival. In conclusion, although AITLs showed a good response to the initial chemotherapy, their response durations were short; therefore, chemotherapy for AITL should be modified or intensified as in high-dose chemotherapy.

Class III beta-tubulin shows unique expression patterns in a variety of neoplastic and non-neoplastic lymphoproliferative disorders.

Class III beta-tubulin (TUBB3) expression in carcinoma is associated with resistance to tubulin-binding chemotherapeutic agents. Recently, follicular dendritic cells (FDCs) were reported to express TUBB3 under physiologic conditions. We investigated TUBB3 expression in a wide range of lymphoproliferative disorders using immunohistochemistry. Dual immunostaining for Bcl-6 and TUBB3 revealed that some germinal center B cells also express TUBB3 in addition to FDCs. In Hodgkin lymphomas (HLs), 47.1% (40/85) expressed TUBB3 in the tumor cells with an all-or-none pattern. TUBB3 expression in HL was more common in mixed cellularity type than nodular sclerosis type (P=0.032). Among non-HLs, 79.3% (23/29) of anaplastic large cell lymphoma (ALCL), 8% (2/25) of extranodal natural killer/T-cell lymphoma, and 75% (21/28) of Burkitt lymphoma showed TUBB3 expression with an all-or-none pattern. Of diffuse large B-cell lymphoma, 15.2% (32/210) expressed TUBB3 in a heterogeneous pattern. In ALCL, TUBB3 expression was more common in systemic ALCL than in primary cutaneous ALCL (P=0.046). Diffuse large B-cell lymphomas with a germinal center B-like subgroup exhibited TUBB3 expression more frequently than non-GCB-like subgroup (P=0.01). Otherwise, none of the 18 angioimmunoblastic T-cell lymphomas; 18 peripheral T-cell lymphomas, not otherwise specified; 12 follicular lymphomas; 62 marginal zone lymphomas; 7 mantle cell lymphomas; 8 small lymphocytic lymphomas; or 2 FDC sarcomas expressed TUBB3. In angioimmunoblastic T-cell lymphoma and Castleman disease, TUBB3 was positive in immunoblasts corresponding to Epstein-Barr virus-infected or Kaposi sarcoma herpes virus-infected cells. A variety of neoplastic and non-neoplastic lymphoproliferative disorders exhibited characteristic TUBB3 expression patterns; these results suggest potential for diagnostic utility, some insight into the pathobiology of TUBB3 expression, and potential therapeutic implications.