Correlation of Bcl-2 Rearrangement With Clinical Characteristics and Outcome in Indolent Follicular Lymphoma

Quantification of DAPK1 promoter methylation in bone marrow and peripheral blood as a follicular lymphoma biomarker

Hypermethylation of DAPK1 promoter gene was found to be a frequent epigenetic alteration in follicular lymphoma (FL). We evaluated whether the quantification of DAPK1 methylation in the bone marrow (BM) and peripheral blood of FL patients at diagnosis and during follow-up provides important prognostic information. DAPK1 methylation was quantitated by real-time MethyLight PCR in 107 patients at diagnosis, at end of therapy, and during follow-up. Information on BCL2-IGH rearrangement and clinical characteristics were available for all patients. Aberrant DAPK1 methylation was found in 22 of 26 (85%) lymph node biopsy samples, 62 of 107 (58%) BM specimens, and 25 of 63 (40%) peripheral blood samples at diagnosis. DAPK1 methylation was greater in patients with BM infiltration and a higher Follicular Lymphoma International Prognostic Index score. The presence of aberrant DAPK1 methylation in BM significantly reduced progression-free survival following immunochemotherapy, independent of Follicular Lymphoma International Prognostic Index score. Residual or increased methylation after treatment was associated with an increased risk for relapse. With watchful waiting, greater DAPK1 methylation at diagnosis was associated with a shorter time to antilymphoma treatment. Our study indicates that quantification of DAPK1 methylation represents a prognostically relevant FL biomarker, with promising implications for risk assessment.

Death receptors in chemotherapy and cancer

Apoptosis, the cell's intrinsic death program, is a key regulator of tissue homeostasis. An imbalance between cell death and proliferation may result in tumor formation. Also, killing of cancer cells by cytotoxic therapies such as chemotherapy, gamma-irradiation or ligation of death receptors is predominantly mediated by triggering apoptosis in target cells. In addition to the intrinsic mitochondrial pathway, elements of death receptor signaling pathways have been implied to contribute to the efficacy of cancer therapy. Failure to undergo apoptosis in response to anticancer therapy may lead to resistance. Also, deregulated expression of death receptor pathway molecules may contribute to tumorigenesis and tumor escape from endogenous growth control. Understanding the molecular events that regulate apoptosis induced by anticancer therapy and how cancer cells evade apoptosis may provide new opportunities for pathway-based rational therapy and for drug development.

Fludarabine, mitoxantrone, dexamethasone (FND) compared with an alternating triple therapy (ATT) regimen in patients with stage IV indolent lymphoma

Treatment for patients with stage IV indolent lymphoma ranges from watchful waiting to intensive chemotherapy and stem cell transplantation. In this trial we compared 2 induction regimens followed by 1 year of interferon maintenance therapy. Fludarabine, mitoxantrone (Novantrone), and dexamethasone (FND) were compared with an alternating triple therapy (ATT) regimen (CHOD-Bleo, ESHAP, and NOPP). Maintenance interferon/dexamethasone was given for 1 year in both treatment arms. Endpoints were comparisons of remission rates, survival, failure-free survival (FFS), molecular response rates, and toxicities. One hundred forty-two patients with previously untreated stage IV indolent lymphoma were evaluable (73 on FND; 69 on ATT). The overall response rates were 97% for FND and 97% for ATT (P =.9). The median follow-up is 5.9 years. The 5-year survival rates were 84% with FND and 82% with ATT (P =.9); the 5-year FFS rates were 41% with FND and 50% with ATT (P =.02). In a multivariate analysis, factors predicting for longer FFS were beta(2)-microglobulin less than 3 mg/L (P =.01) and ATT treatment (P =.03). ATT was associated with a substantially higher rate of grade 3-4 toxicities than FND. In conclusion, both regimens were associated with high rates of response and survival. ATT was associated with substantially longer FFS, but it was more toxic than FND.

Molecular detection of tumor cells at diagnosis invading the bone marrow and peripheral blood of patients with aggressive or indolent lymphomas

We studied tumor cell invasions of bone marrow and peripheral blood in patients with various types of advanced non-Hodgkin's lymphoma by amplifying complementarity determining region III using the polymerase chain reaction (PCR) method and developing patient-specific probes. After molecular engineering, we could detect tumor cells in bone marrow from seven of 11 cases and in peripheral blood from six of 11 cases, despite negative results in four cases studied morphologically. Indolent cases were more likely to yield positive results than aggressive cases. The reason may be different biological behaviors among the histological types.

The significance of molecular response of follicular lymphoma to central lymphatic irradiation as measured by polymerase chain reaction for t(14;18)(q32;q21)

BACKGROUND

More than 80% of the patients with follicular lymphoma have a characteristic chromosomal translocation, t(14;18)(q32;q21), at the major breakpoint region (MBR) or minor cluster region (MCR) involving the bcl-2 oncogene. This study was undertaken to assess the significance of the molecular response rate measured by the polymerase chain reaction (PCR) evidence of translocation among patients with Stage I to III follicular lymphoma treated with central lymphatic irradiation (CLI).

METHODS AND MATERIALS

Thirty-three patients with Stage I-III follicular lymphoma were treated with CLI on a prospective protocol. Bone marrow and peripheral blood samples were obtained before CLI for PCR analysis of t(14;18)(q32; q21). PCR-positive patients were followed by PCR analysis at regular intervals during and after CLI, and the results were correlated with clinical outcome. The following pretreatment factors were also investigated for their relationship to relapse and molecular response: gender, age, lactate dehydrogenase (LDH) and beta-2 microglobulin (beta2M) levels, Ann Arbor stage, and International Prognostic Index (IPI) for malignant lymphoma.

RESULTS

The subjects were 19 men and 14 women, with a median age of 52 years (range 30-69), who started CLI between January 1993 and February 1998. Median follow-up was 44 months (range 12-67), and all but 2 patients were still alive at the last follow-up. Four patients were Stage IA, 8 were Stage IIA, 19 were Stage IIIA, and 2 were Stage IIIB. Two patients had abnormal LDH levels (> 618 U/dL) and 7 patients had abnormal beta2M levels (> 2 mg/dL). Nine patients had IPI = 0, 16 had IPI = 1, and 8 had IPI = 2. All patients achieved complete response (CR). Twelve patients have relapsed to date. The median overall time to relapse was 54 months. The actuarial proportion of patients free from relapse at 3 years was 87% (95% confidence interval [CI] 69-95%). A total of 287 PCR results were available, 64 from bone marrow and 223 from peripheral blood. Pretreatment PCR data were available for 27 patients, of whom 21 were positive and 3 were unambiguously negative (in blood and bone marrow for both MBR and MCR). For the 19 PCR positive patients for whom we had post-treatment results, there was a clear and steady decreasing trend toward loss of PCR positivity (49% positive for bone marrow and 32% positive for peripheral blood at 3 years). There was a clear trend for increasing PCR positivity with increasing IPI: 10% for IPI = 0, 31% for IPI = 1, and 63% for IPI = 2 at 3 years for blood. The same trend was also observed for bone marrow. The IPI was the only statistically significant predictor for relapse with a relapse-free survival of 91% at 3 years for IPI < 2 and 75% for IPI = 2 (p = 0.024, log-rank test).

CONCLUSION

Molecular response to CLI occurs gradually over years. High IPI is a negative predictor for molecular response and relapse-free survival.

Nonimmunoglobulin (non-Ig)/BCL6gene fusion in diffuse large B-cell lymphoma results in worse prognosis than Ig/BCL6

Chromosomal translocation involving the BCL6 gene affects not only immunoglobulin (Ig) genes but also a number of non-Ig genes as partners. The molecular anatomy of the BCL6 gene rearrangements in 39 cases with diffuse large B-cell lymphoma (DLBCL) by long-distance polymerase chain reaction–based assays was determined. The results showed that Iggenes were affected in 21 cases; non-Ig genes, 15 cases; a deletion of more than a 1-kb segment, 2 cases; and a point mutation, 1 case. Comparative studies between the 21 cases withIg gene partners and the 17 cases with non-Iggene partners, including 2 cases with the deletion, showed that the overall survival of the latter group of patients was significantly inferior to that of the former (P = .0440), and the estimated 2-year overall survival rates were 58.3% vs 17.6% (P = .005). Non-Ig/BCL6 fusion is a poor prognostic indicator of DLBCL, and DLBCL with BCL6translocation could be subclassified according to the individual partner locus and/or gene.