13q deletion in chronic lymphocytic leukemia: characterization of E4.5, a novel chromosome condensation regulator-like guanine nucleotide exchange factor.

We report the characterization of a new gene (E4.5) that maps at chromosome band 13q14.3, a chromosomal area frequently deleted in chronic lymphocytic leukemia (CLL) and in other lymphoid malignancies. E4.5 gene encodes for a 4 kb mRNA expressed in various tissues and has an open reading frame of 531 amino acids. The predicted E4.5 protein shows strong homology with the human regulator of chromosome condensation (RCC1) protein, the principal GTP exchange factor for Ran protein. The E4.5 protein contains a BTB domain in its N-terminus, a protein-protein interaction motif. Therefore, we propose that E4.5 is a new member of the RCC1-related guanine nucleotide exchange factor (GEF) family with potent interaction with other proteins and unknown function. Until now, no tumor suppressor genes have been mapped in the 13q14.3 minimal deleted region (MDR) in patients with CLL. It has been proposed that loss of the 13q14.3 MDR may contribute to lymphoid neoplasia by altering the expression/function of genes located on 13q14.3 outside the MDR. The E4.5 is one of these genes with a potential role in the pathogenesis of CLL.

Survival and prognostic factors after initiation of treatment in Waldenstrom's macroglobulinemia.

BACKGROUND: Waldenstrom's macroglobulinemia (WM) is an unusual lymphoplasmacytoid lymphoma characterized by the presence of a serum monoclonal immunoglobulin M. Although several studies have evaluated possible prognostic factors of this disease, few have focused on the survival and prognosis of symptomatic patients after the initiation of treatment. PATIENTS AND METHODS: Our study included 122 previously untreated patients with a median age of 67 years who required systemic treatment. Multiple variables were analyzed for their prognostic value on survival after initiation of treatment using univariate and Cox regression multivariate analysis. RESULTS: The median overall survival was 106 months. Pretreatment factors associated with shorter survival were age >/=65 years, splenomegaly, B-symptoms (weight loss, fever or night sweats), hemoglobin <10 g/dl, platelets <100 x 10(6)/dl, albumin <3.5 g/dl and bone marrow lymphoplasmacytic infiltrate >/=50%. In the multivariate analysis, the two variables with independent prognostic value were age >/=65 years and hemoglobin <10 g/dl. Furthermore, we were able to divide our patients into three risk groups based on the presence of two, one or none of these two adverse prognostic factors. The median survival times in the high-, intermediate- and low-risk groups were 46 months, 107 months and 172 months, respectively (P <0.0001). DISCUSSION: Our findings suggest that advanced age and anemia appear to be the two dominant prognostic factors for survival after initiation of treatment in patients with WM. These two readily available parameters can stratify the patients into three distinct subgroups and may help the selection of appropriate treatment.

Thalidomide and dexamethasone combination for refractory multiple myeloma.

BACKGROUND: Thalidomide is effective in approximately 30% of patients with refractory multiple myeloma. Dexamethasone is active in 25% of patients with disease resistant to alkylating agents. We investigated the combination of thalidomide with dexamethasone as salvage treatment for heavily pretreated patients with multiple myeloma, in order to assess its efficacy and toxicity. PATIENTS AND METHODS: Forty-four patients with refractory myeloma were treated with thalidomide, 200 mg p.o. daily at bedtime, with dose escalation to 400 mg after 14 days, and dexamethasone, which was administered intermittently at a dose of 20 mg/m2 p.o. daily for four days on day 1-4, 9-12, 17-20, followed by monthly dexamethasone for four days. Patients' median age was 67 years. All patients were resistant to standard chemotherapy, 77% were resistant to dexamethasone-based regimens and 32% had previously received high-dose therapy. RESULTS: On an intention-to-treat basis twenty-four patients (55%) achieved a partial response with a median time to response of 1.3 months. The thalidomide and dexamethasone combination was equally effective in patients with or without prior resistance to dexamethasone-based regimens and in patients with or without prior high-dose therapy. Toxicities were mild or moderate and consisted primarily of constipation, morning somnolence, tremor, xerostomia and peripheral neuropathy. The median time to progression for responding patients is expected to exceed 10 months and the median survival for all patients is 12.6 months. CONCLUSION: The combination of thalidomide with dexamethasone appears active in patients with refractory multiple myeloma. If this activity is confirmed, further studies of this combination as second-line treatment for patients resistant to conventional chemotherapy, and as primary treatment for patients with active myeloma, should be considered.