It has become clear that cancer is not merely a growth of autonomously proliferating cells, but that other non-malignant cell types are a functional part of the disease. Immune cells, fibroblasts, specialized mesenchymal cells and microvasculature together make up the tumour microenvironment and have functional interactions with tumour cells. Classical Hodgkin's lymphoma (cHL) is characterized by only a few malignant cells and an abundance of inflammatory cells. Hodgkin and Reed-Sternberg (HRS) cells are surrounded by T and B cells admixed with plasma cells, macrophages, eosinophils and mast cells. A constitutive activity of NF-kappaB and an altered JAK-STAT signalling pathway are part of the biological background associated with the increased expression of cytokines and cytokine receptors seen in HRS cells. Over-expression of the members of the TNF receptor family, especially CD30 and CD40, is a hallmark of HRS cells. cHL is a tumour where aberrant cytokine production contributes not only to the proliferation of HRS cells but also to the maintenance of an appropriate environment for the tumour cells. In addition, several chemokines contribute to the composition of the inflammatory background in cHL. This review summarizes updated information on the complex interactions between the HRS cells and their tissue microenvironment and highlights the development of newer therapeutic strategies aimed at targeting the non-malignant inflammatory/immune cellular components of HL that are involved in cancer cell growth and/or immune escape.

Increasing evidence suggests that bone marrow-derived mesenchymal stem cells (MSCs) are recruited into the stroma of developing tumors where they contribute to cancer progression. MSCs produce different growth factors that sustain tumor-associated neo-angiogenesis. Since the majority of carcinomas secrete ligands of the epidermal growth factor receptor (EGFR), we assessed the role of EGFR signaling in regulating the release of angiogenic factors in MSCs. Treatment of human primary MSCs and of the human osteoblastic cell line hFOB with transforming growth factor α (TGF-α), one of the main ligands of the EGFR, significantly induced activation of this receptor and of different intracellular signaling proteins, including the PI3K/AKT and the MEK/MAPK pathways. TGF-α induced a significant increase in the levels of secretion of vascular endothelial growth factor in both MSCs and hFOB. Conditioned medium from TGF-α treated MSCs showed an higher in vivo angiogenic effect as compared with medium from untreated cells. Treatment of MSCs with TGF-α also produced a significant increase in the secretion of other angiogenic growth factors such as angiopoietin-2, granulocyte-colony stimulating factor, hepatocyte growth factor, interleukin (IL)-6, IL-8, and platelet-derived growth factor-BB. Using selective MEK and PI3K inhibitors, we found that both MEK/MAPK and the PI3K/AKT signaling pathways mediate the ability of TGF-α to induce secretion of angiogenic factors in MSCs. Finally, stimulation with TGF-α increased the ability of MSCs to induce migration of MCF-7 breast cancer cells. These data suggest that EGFR signaling regulates the ability of MSCs to sustain cancer progression through the release of growth factors that promote neo-angiogenesis and tumor cell migration.

Autoimmune hemolytic anemia (AIHA) is a well-known complication of chronic lymphocytic leukemia (CLL). In recent years the anti-CD20 monoclonal antibody rituximab has been used for the therapy of steroid-refractory AIHA and autoimmune thrombocytopenia, either idiopathic or in association with CLL. We report the results of rituximab treatment for 14 patients suffering from CLL-associated AIHA. They developed a direct antiglobulin test positive AIHA at a mean time of 47 months (range 0-135 months) from the diagnosis of CLL. In 3 cases AIHA was diagnosed at the same time as CLL. Only 1 patient had fludarabine-related AIHA. All patients received steroids as first-line treatment. At a mean time of 46 days (range 1-210 days) from the diagnosis of AIHA all patients received rituximab at a dosage of 375 mg/m 2 /weekly for 4 weeks. All patients except 3 (2 died of cardiac failure or sepsis soon after the third cycle and 1 HCV-positive patient experienced a rise in serum amino transferases) completed the scheduled four programmed cycles. First injection side effects of rituximab were minimal. All but 2 patients showed an increase in hemoglobin levels in response to rituximab (mean value 3.6 g/dl; range 0.7-10 g/dl) and a reduction in the absolute lymphocyte count and lymph nodes and spleen volume. Nine patients required packed red cell transfusions before starting rituximab; 5 no longer needed transfusions just after the second cycle and another patient after the fourth cycle. Three patients (22%) were considered to fully respond and 7 (50%) only responded partially. At a mean follow-up of 17 months, 8 patients were still alive, 6 of them transfusion-free. Our results prove that the anti-CD20 monoclonal antibody is an effective and well-tolerated alternative treatment for CLL-associated AIHA. Am. J. Hematol. 81:598-602, 2006. V V C 2006 Wiley-Liss, Inc.

The clinical and pathological features of classical Hodgkin lymphoma (cHL) mirror an abnormal tissue and systemic immune response due to the production of a variety of cytokines and chemokines by the malignant Hodgkin‐Reed‐Sternberg (H‐RS) cells and/or surrounding reactive cells. Here, we demonstrate that HL‐derived cell lines (L‐428, KM‐H2, HDLM‐2, L‐1236 and L‐540) and primary H‐RS cells from lymph node tissues of HL patients express the IL‐7(R) receptor. IL‐7 appears to be involved in autocrine circuitries of HL because L‐1236, HDLM‐2 and KM‐H2 cells display the constitutive production of IL‐7 and neutralizing anti‐IL‐7 antibodies induces a statistically significant inhibition of their basal proliferation. In addition, IL‐7, either exogenous or fibroblasts‐derived, promotes the clonogenic growth and reduces apoptosis of cultured H‐RS cells, being also able to partially protect these cells from the cytotoxic effects of doxorubicin. We also provide evidence that IL‐7 stimulates IL‐6 secretion from IL‐7R‐expressing fibroblasts from HL‐involved lymph nodes (HLFs), and that a striking increase in IL‐6 secretion can be observed in cocultures of HLFs with L1236 cells. Finally, we show that L‐1236 cells‐derived IL‐7 represents a costimulator for proliferation of purified CD4+CD25+CD127dim/− regulatory T cells (Tregs). Taken together, our data indicates that the IL‐7/IL‐7R axis constitutes an additional signaling pathway between H‐RS cells and their reactive cellular background, thereby affecting proliferation and survival of tumor cells, acting as a cofactor for Tregs expansion and enhancing the microenviromental production of IL‐6, a cytokine associated with the presence of “B” symptoms and a poor outcome in HL patients. © 2009 UICC

Integrin activation is a multifaceted phenomenon leading to increased affinity and avidity for matrix ligands. To investigate whether cytokines produced during stromal infiltration of carcinoma cells activate nonfunctional epithelial integrins, a cellular system of human thyroid clones derived from normal glands (HTU-5) and papillary carcinomas (HTU-34) was employed. In HTU-5 cells, αvβ3 integrin was diffused all over the membrane, disconnected from the cytoskeleton, and unable to mediate adhesion. Conversely, in HTU-34 cells, αvβ3 was clustered at focal contacts (FCs) and mediated firm attachment and spreading. αvβ3 recruitment at FCs and ligand-binding activity, essentially identical to those of HTU-34, occurred in HTU-5 cells upon treatment with hepatocyte growth factor/scatter factor (HGF/SF). The HTU-34 clone secreted HGF/SF and its receptor was constitutively tyrosine phosphorylated suggesting an autocrine loop responsible for αvβ3 activated state. Antibody-mediated inhibition of HGF/SF function in HTU-34 cells disrupted αvβ3 enrichment at FCs and impaired adhesion. Accordingly, activation of αvβ3 in normal cells was produced by HTU-34 conditioned medium on the basis of its content of HGF/SF. These results provide the first example of a growth factor–driven integrin activation mechanism in normal epithelial cells and uncover the importance of cytokine-based autocrine loops for the physiological control of integrin activation.

SummaryThe management of patients with Hodgkin lymphoma (HL) recurring after stem cell transplantation (SCT) and multiply relapsed disease remains challenging. We report on 41 such patients who received bendamustine hydrochloride, a bifunctional mechlorethamine derivative mechanistically unrelated to traditional alkylators, after a median of four prior chemotherapy lines, including SCT in 85% of cases. Bendamustine was given at doses of 90-120 mg/m 2 every 21 or 28 d. At first assessment (2-4 cycles), the overall response rate (ORR) was 78% with 12 (29%) complete (CR) and 20 (49%) partial responses (PR). Upon treatment prolongation to 6-8 courses, 40% of PRs progressed, yielding a final ORR of 58% with 31% of CRs. Eight patients (two CRs, six PRs) were subsequently allotransplanted. Median progression-free and overall survival exceeded 11 and 21 months respectively; complete responders displayed a median disease-free survival above 9 months with a relapse rate of only 30%. Outcomes were independent of disease chemosensitivity, previous transplant and bendamustine dose-intensity. No life-threatening or unexpected adverse events occurred.Within the limits of a retrospective analysis and schedule heterogeneity, these results appear very encouraging and prompt prospective trials to confirm bendamustine as a valuable option in the palliative setting and in cytoreductive strategies before allotransplantation.

Summary Specific trials on adult Burkitt lymphoma (BL) and ‘unclassifiable’ lymphomas with features intermediate between BL and diffuse large B‐cell lymphoma (BL/DLBCL) are advocated which include substantial numbers of older patients, to improve treatment feasibility, while countering risks of systemic and central nervous system (CNS) recurrences. We prospectively evaluated a modified CODOX‐M/IVAC (CODOX‐M: cyclophosphamide, vincristine, doxorubicin, high‐dose methotrexate; IVAC: ifosfamide, etoposide and high‐dose cytarabine) regimen by the addition of rituximab (R) and liposome‐encapsulated cytarabine (D) to increase antitumour activity and halve the number of intrathecal treatments. Thirty adults (40% >60 years) with BL (n = 15) and BL/DLBCL (n = 15) were accrued. Primary endpoints were progression‐free survival (PFS), CNS recurrence, and liposomal cytarabine‐associated toxicity. Eighty percent of patients received the whole treatment programme, the remaining cases received at least three full courses. Application of the RD‐CODOX‐M/IVAC regimen resulted in remarkable 4‐year PFS (78%) and complete remission (CR) rates (93%). However, PFS was significantly lower in patients older than 60 years as compared to younger ones (49%vs 93%, P = 0·03; median, 36 months), despite high actual dose‐intensity, CR rate and tolerability. Reduced‐intensity intratechal prophylaxis through liposomal cytarabine was effective because the CNS failure rate was low (3·4%) and without severe neurological toxicities. The RD‐CODOX‐M/IVAC strategy is feasible and highly effective, but improving outcomes in elderly patients remains a priority.

Cytarabine is a pyrimidine nucleoside analog, commonly used in multiagent chemotherapy regimens for the treatment of leukemia and lymphoma, as well as for neoplastic meningitis. Ara-C-based chemotherapy regimens can induce a suboptimal clinical outcome in a fraction of patients. Several studies suggest that the individual variability in clinical response to Leukemia & Lymphoma treatments among patients, underlying either Ara-C mechanism resistance or toxicity, appears to be associated with the intracellular accumulation and retention of Ara-CTP due to genetic variants related to metabolic enzymes. Herein, we reported (a) the latest Pharmacogenomics biomarkers associated with the response to cytarabine and (b) the new drug formulations with optimized pharmacokinetics. The purpose of this review is to provide readers with detailed and comprehensive information on the effects of Ara-C-based therapies, from biological to clinical practice, maintaining high the interest of both researcher and clinical hematologist. This review could help clinicians in predicting the response to cytarabine-based treatments.