Final 3-year Results of the Dasatinib Discontinuation Trial in Patients With Chronic Myeloid Leukemia Who Received Dasatinib as a Second-line Treatment.

INTRODUCTION: We previously reported an interim analysis of the DADI (dasatinib discontinuation) trial. The results showed that 48% of patients with chronic myeloid leukemia in the chronic phase who maintained a deep molecular response (DMR) for ≥ 1 year could discontinue second- or subsequent-line dasatinib treatment safely at a median follow-up of 20 months. However, the results from longer follow-up periods would be much more useful from a clinical perspective. PATIENTS AND METHODS: The DADI trial was a prospective, multicenter trial conducted in Japan. After confirming a stable DMR for ≥ 1 year, dasatinib treatment subsequent to imatinib or nilotinib was discontinued. After discontinuation, the loss of DMR (even of 1 point) was defined as stringent molecular relapse, thereby triggering therapy resumption. The predictive factors of treatment-free remission (TFR) were analyzed. RESULTS: The median follow-up period was 44.0 months (interquartile range, 40.5-48.0 months). The estimated overall TFR rate at 36 months was 44.4% (95% confidence interval, 32.0%-56.2%). Only 2 patients developed a molecular relapse after the 1-year cutoff point. The presence of imatinib resistance was a significant risk factor for molecular relapse. Moreover, high natural killer cell and low γδ+ T-cell and CD4+ regulatory T-cell (CD25+CD127low) counts before discontinuation correlated significantly with successful therapy discontinuation. CONCLUSION: These findings suggest that discontinuation of second- or subsequent-line dasatinib after a sustained DMR of ≥ 1 year is feasible, especially for patients with no history of imatinib resistance. In addition, the natural killer cell count was associated with the TFR.

Role of microRNA-29b in myelodysplastic syndromes during transformation to overt leukaemia.

Chromosome 7q32 is a frequently deleted region in myelodysplastic syndromes (MDSs) and encodes the microRNAs (miRNAs) miR-29a/miR-29b. Both miR-29s down-regulate the anti-apoptotic protein myeloid cell leukaemia 1 (MCL-1) in acute myeloid leukaemia. Thus, to investigate the role of miR-29s in the transformation of MDS to overt leukaemia (OL), we analysed the relationship between miR-29 expression and MCL-1 expression. MiR-29b expression was down-regulated in refractory anaemia and OL bone marrow as compared to that in control bone marrow. MCL-1 expression level in OL was significantly higher than that in refractory anaemia with excess blasts and a negative correlation was observed between miR-29b and MCL-1 messenger RNA expression levels in OL samples. Immunohistochemical analysis showed that the MCL-1 positive rate among MDS bone marrow CD34 positive cells significantly increased during transformation to OL. Additionally, MCL-1 positive cells were negative for cleaved caspase 3, which indicated that these cells avoided apoptosis. Reduced miR-29b expression in MDS bone marrow cells might trigger transformation to OL via overexpression of MCL-1 in blastic cells.

Discontinuation of dasatinib in patients with chronic myeloid leukaemia who have maintained deep molecular response for longer than 1 year (DADI trial): a multicentre phase 2 trial.

BACKGROUND: First-line imatinib treatment can be successfully discontinued in patients with chronic myeloid leukaemia after deep molecular response has been sustained for at least 2 years. We investigated the safety and efficacy of discontinuing second-line or subsequent dasatinib after at least 1 year of deep molecular response. METHODS: The Dasatinib Discontinuation trial was a prospective multicentre trial done in Japan. Eligible patients taking dasatinib and with confirmed stable deep molecular response were enrolled between April 1, 2011, and March 31, 2012. All patients received dasatinib consolidation therapy for at least 1 year. In those with sustained deep molecular response, dasatinib was discontinued. Patients were followed up every month in year 1 (clinical cutoff), every 3 months in year 2, and every 6 months in year 3 for deep molecular response and immunological profiles. The primary endpoint was the proportion of patients with treatment-free remission at 6 months after discontinuation. Molecular relapse was defined as loss of deep molecular response at any assessment. This study is registered, number UMIN000005130. FINDINGS: 88 patients were enrolled in the consolidation phase, 24 were excluded from the discontinuation phase due to fluctuations in BCR-ABL1 transcript levels. One patient was excluded because of positive expression of major and minor BCR-ABL1 transcripts in chronic myeloid leukaemia cells and the detection of minor BCR-ABL1 transcripts during consolidation. Thus, 63 patients discontinued dasatinib treatment. The 25 patients who were excluded from discontinuation continued to receive dasatinib and none showed disease progression. Median follow-up was 20.0 months (IQR 16.5-24.0). Of the 63 patients who discontinued and were not excluded, 30 patients maintained deep molecular response while 33 patients had molecular relapses, all within the first 7 months after discontinuation. The estimated overall treatment-free remission was 49% (95% CI 36-61) at 6 months. No severe treatment-related toxic effects were seen. Treatment was restarted in the 33 patients with relapse; rapid molecular responses were seen in all 33 patients, of whom 29 (88%) regained deep molecular response within 3 months, as did the remaining four by 6 months. INTERPRETATION: Dasatinib discontinuation after sustained deep molecular response for more than 1 year is feasible. FUNDING: Epidemiological and Clinical Research Information Network (ECRIN).

Lipopolysaccharide-Induced CXCL10 mRNA Level and Six Stimulant-mRNA Combinations in Whole Blood: Novel Biomarkers for Bortezomib Responses Obtained from a Prospective Multicenter Trial for Patients with Multiple Myeloma.

To identify predictive biomarkers for clinical responses to bortezomib treatment, 0.06 mL of each whole blood without any cell separation procedures was stimulated ex vivo using five agents, and eight mRNAs were quantified. In six centers, heparinized peripheral blood was prospectively obtained from 80 previously treated or untreated, symptomatic multiple myeloma (MM) patients with measurable levels of M-proteins. The blood sample was procured prior to treatment as well as 2-3 days and 1-3 weeks after the first dose of bortezomib, which was intravenously administered biweekly or weekly, during the first cycle. Six stimulant-mRNA combinations; that is, lipopolysaccharide (LPS)-granulocyte-macrophage colony-stimulating factor (GM-CSF), LPS-CXCL chemokine 10 (CXCL10), LPS-CCL chemokine 4 (CCL4), phytohemagglutinin-CCL4, zymosan A (ZA)-GMCSF and ZA-CCL4 showed significantly higher induction in the complete and very good partial response group than in the stable and progressive disease group, as determined by both parametric (t-test) and non-parametric (unpaired Mann-Whitney test) tests. Moreover, LPS-induced CXCL10 mRNA expression was significantly suppressed 2-3 days after the first dose of bortezomib in all patients, as determined by both parametric (t-test) and non-parametric (paired Wilcoxon test) tests, whereas the complete and very good partial response group showed sustained suppression 1-3 weeks after the first dose. Thus, pretreatment LPS-CXCL10 mRNA and/or the six combinations may serve as potential biomarkers for the response to bortezomib treatment in MM patients.

A phase 1/2 study of bosutinib in Japanese adults with Philadelphia chromosome-positive chronic myeloid leukemia.

This phase 1/2 study evaluated the safety and pharmacokinetics (part 1) and efficacy and safety (part 2) of bosutinib in Japanese Philadelphia chromosome-positive (Ph+) chronic-phase (CP) or advanced-phase chronic myeloid leukemia (CML) patients resistant/intolerant to previous imatinib (2L) or imatinib+dasatinib/nilotinib (3L). Based on dose-limiting toxicities and previous studies, the part 2 bosutinib starting dose was 500 mg/day (n = 63). For CP CML 2L (n = 28), the cumulative major cytogenetic response (MCyR) rate by week 24 was 36 % (primary endpoint); the cumulative major molecular response (MMR) rate through the study was 43 %. Transformation to accelerated/blast phase (AP/BP) was observed in one patient. Progression-free survival (PFS) and overall survival (OS) rates at 96 weeks were 94 and 96 %, respectively. Of seven advanced-phase 2L patients, one had confirmed complete hematologic response at week 84, and one had AP/BP transformation. PFS and OS rates at week 96 were 21 and 43 %. For 3L (n = 11), cumulative MCyR rate by week 24 was 18 %; cumulative MMR rate was 18 %; no transformations occurred. Common non-hematologic adverse events (AEs) were diarrhea (95 %), rash (57 %), and nasopharyngitis (51 %). Sixteen patients discontinued due to adverse events; no deaths occurred within 30 days of the last dose. Bosutinib 500 mg/day demonstrated efficacy and manageable toxicity in Japanese Ph+ CML patients resistant/intolerant to imatinib.

Expression of multidrug resistance 1 gene in association with CXCL12 in chronic myelogenous leukaemia.

Even though the BCR-ABL tyrosine kinase inhibitor imatinib significantly improves the prognosis of chronic myelogenous leukaemia (CML) patients, drug resistance is a major obstacle to better management. We examined the interaction of recently defined bone marrow microenvironment factors CXCL12 and ATP-binding cassette (ABC) transporters in the bone marrow of CML patients in the chronic phase and blast crisis.Expression levels of mRNA extracted from frozen specimens of CML patients were measured by real-time polymerase chain reaction. The expression of the ABC transporters MDR1, ABCC1, ABCG2, and CXCL12 was significantly higher in the bone marrow samples of CML blast crisis than in those of CML chronic phase. Immunohistochemical staining for CXCL12 revealed that the proportion of CXCL12 positive reticular cell areas correlated well with the mRNA levels of CXCL12 in CML bone marrow. Finally, co-culture experiments of K562 CML cells with CXCL12 expressing mesenchymal cells (OP9 cells or human CXCL12 transfected 3T3 cells) revealed enhanced mRNA levels for MDR1 in a CXCL12 rich environment.These results suggest that imatinib treatment restores the bone marrow microenvironment in CML with the presence of CXCL12 expressing reticular cells but in turn induces the overexpression of MDR1 in haematopoietic cells due to up-regulated expression of CXCL12.

Impacts of new agents for multiple myeloma on development of secondary myelodysplastic syndrome and acute myeloid leukemia.

The use of new agents (NAs) such as bortezomib, thalidomide, and lenalidomide has extended the survival of patients with multiple myeloma (MM). However, whether long-term treatment using NAs may increase the risk of second primary malignancies is a concern. Three hundred and thirty-three patients with MM were treated at our hospital from 1998 to 2013. Additional chromosomal abnormalities (CAs), associated with secondary myelodysplastic syndrome/acute myeloid leukemia, were observed in 13 of 152 users of NAs, but in 38 of 181 non-users of NAs. The cumulative CA incidence was higher in non-users of NAs. The CAs frequently observed were 13q-, 20q-, +8 in users of NAs, while -5/5q- and -7/7q- were detected in non-users of NAs. The total dose and treatment period of NAs did not differ between CAs-positive and -negative patients. However, a higher dose of melphalan was observed to have been used in patients who had CAs. Longer follow-up periods are necessary for an accurate risk assessment.

[Increased level of KL-6 in a BJP-λ-type multiple myeloma patient with poor prognosis].

A 63-year-old female with BJP-multiple myeloma (Durie-Salmon stage III B, International Staging System III) showed an increased level of KL-6, a sialylated carbohydrate antigen that is a MUC1 molecule expressed in type II pneumocytes and reflects activity of interstitial pneumonia. At the time of diagnosis, KL-6 was as high as 22,030 U/ml; however, surfactant protein D (SP-D) was normal, and stroma-related pneumonia was not indicated on CT images. Expression of KL-6 in multiple myeloma cells was detected by immunostaining and the patient was diagnosed with KL-6-positive multiple myeloma. Usually, MUC1 is encoded by chromosome 1q21, but the karyotypic analysis of the patient's bone marrow cells lacked chromosome 1. KL-6 increased as the disease progressed. The patient did not respond to chemotherapy, including bortezomib, showed an increase of pleural effusion, and died. For this patient, multiple myeloma with high KL-6 was refractory to chemotherapy, suggesting that new treatment strategies, including transplantation of hematopoietic stem cells, are required.

Intensive chemotherapy for elderly patients with acute myelogeneous leukemia: a propensity score analysis by the Japan Hematology and Oncology Clinical Study Group (J-HOCS).

The prognosis of acute myelogenous leukemia (AML) in the elderly patients is extremely poor. Although several previous studies have suggested that intensive chemotherapy is associated with a better prognosis, there may have been a selection bias. Therefore, we retrospectively evaluated the impact of intensive chemotherapy for AML in the elderly by stratifying patients according to a propensity score. Eighty-one AML patients aged 70 years or more were included in this study. Patients with acute promyelocytic leukemia were not included. A propensity score for the use of intensive chemotherapy was calculated from four factors at diagnosis. Forty-five patients received intensive chemotherapy, whereas 36 received low-dose or no chemotherapy. We stratified the patients into quartiles based on the propensity score. The numbers of patients in the first, second, third, and forth quartiles who received intensive chemotherapy were 5 of 21, 10 of 20, 12 of 20, and 18 of 20, respectively. A stratified log-rank test showed significantly better overall survival in the intensive chemotherapy group (P = 0.0088). Especially, in the combined second and third quartiles, which showed an equal tendency for intensive and non-intensive strategies; overall survival at 3 years was 37.5 % for the intensive chemotherapy group and 13.0 % for the non-intensive chemotherapy group (P = 0.0022). A conventional multivariate analysis confirmed that intensive chemotherapy was beneficial (hazard ratio 0.50, 95 % confidence interval 0.27-0.93, P = 0.028). In conclusion, intensive chemotherapy may prolong overall survival in elderly AML patients who are considered to be able to tolerate such treatment based on factors at diagnosis.

Clinical efficacy and safety of biapenem for febrile neutropenia in patients with underlying hematopoietic diseases: a multi-institutional study.

A multi-institutional study was conducted to assess efficacy and safety of biapenem (BIPM), a carbapenem antibiotic, as an initial-stage therapeutic agent for febrile neutropenia (FN) in patients with hematopoietic diseases. A total of 216 patients from 25 medical institutions were enrolled in this study; of these, 204 were included in the safety analysis and 178 in the efficacy analysis. The combined (excellent and good) response rate was 67.9%, and antipyretic effect (subsidence + tendency to subsidence) was achieved within 3 and 5 days of treatment in 67.3 and 75.9% of patients, respectively. Thus, the clinical responses were gratifying. A response rate of 61.7% (37/60) was observed even in high-risk FN patients in whom neutrophil counts prior to and at 72 h after the start of BIPM were ≤100/µl. BIPM is considered to be a highly promising drug, with prompt onset of clinical benefit, as an initial-stage therapeutic agent for the treatment of FN in patients with hematopoietic diseases.

Differential expression of Toll-like receptors in follicular lymphoma, diffuse large B-cell lymphoma and peripheral T-cell lymphoma.

Although Toll-like receptors (TLRs) in mammals are well-known to play important roles in innate immunity, newer roles for the TLRs have suggested that cells with aberrant TLR expression may have a survival advantage over normal cells. Lymphocytes are one of a small number of cell types that express many of the TLRs, suggesting that abnormal TLR levels/signaling may potentially influence the progression of malignant lymphomas. Thus, frozen samples of 51 lymph nodes from patients with follicular lymphoma (FL), diffuse large B-cell lymphoma (DLBCL) and peripheral T-cell lymphoma (PTCL) were analyzed for the expression of TLR1 to 9 using quantitative real-time PCR, and compared to those in reactive lymphadenopathy (RL) samples. TLR2 was over-expressed in both DLBCL and PTCL but not in FL when compared to RL. TLR1 and TLR4 expression was up-regulated in PTCL, while TLR8 was highly expressed in DLBCL. Although TLR5 showed lower expression in FL, expression of TLR3, TLR6, TLR7 and TLR9 did not vary significantly between different lymphoma subtypes. Double immunostaining revealed an increase in the number of TLR2 and/or TLR8 expressing lymphoma cells in DLBCL. In PTCL, TLR2 and TLR4 expression was localized to neoplastic T cells. TLR expression is highly variable among lymphoma subtypes. However, despite this some significant differences exist that may prove useful in the development of novel therapeutic strategies.

Expression of Toll-like receptor 9 in bone marrow cells of myelodysplastic syndromes is down-regulated during transformation to overt leukemia.

Toll-like receptors (TLRs) play a crucial role in the host defense against invading microorganisms by recognizing pathogen-associated molecular patterns. Recently, a number of endogenous molecules have been reported to be ligands of TLRs. Some of these molecules are known to be expressed in cancer tissue and activate intracellular signal pathways via TLRs during cancer progression. Thus, in the present study, we analyzed the expression dynamics of TLRs in the bone marrow of myelodysplastic syndromes (MDS) during the course of transformation to overt leukemia (OL) using real-time RT-PCR. MDS bone marrow cells at the time of initial diagnosis tended to express higher levels of TLR2, TLR4 and TLR9 than control bone marrow cells. Among these TLRs, TLR9 exhibited a significant decrease of expression at the time of transformation to OL. The expression of TLR9 and TNF-alpha showed significant correlation in bone marrow cells from patients with MDS and OL. Immunohistochemically, TLR2 was mostly localized to neutrophils of the control and MDS bone marrow. TLR4 was observed in a subset of neutrophils and a few mononuclear cells in control and MDS bone marrow. In addition, TLR4 was weakly expressed in nearly half of immature myeloid cells of MDS cases. TLR9 was mainly localized to neutrophils in the control and RA bone marrow and strongly expressed in the immature myeloid cells of RAEB cases, although the blastic cells of OL cases did not express TLR9. Bone marrow cells in MDS exhibit frequent apoptosis, while OL cells are prone to be immortal. Thus, TLR9 might be associated with regulation of apoptotic/proliferative signals via TNF-alpha in the MDS bone marrow.

Evaluation of the risk factors for febrile neutropenia associated with hematological malignancy.

Febrile neutropenia (FN) can frequently become a very serious problem. In 2002, Klastersky and colleagues established the Multinational Association for Supportive Care in Cancer (MASCC) score, which consisted of risk factors for conditions that included solid tumors. However, hematopoietic tumors, in comparison to solid tumors, are plagued by such problems as the quantity and quality of abnormalities associated with leukocytes and neutrophils and the requirement for higher dosages of both radio- and chemotherapy. FN is a complication associated with hematological malignancies that can lead to a fatal outcome, but it is avoidable if the appropriate preventive treatment is performed at an early stage. The subjects of the present study consisted of 354 patients with hematopoietic malignancies who were treated at the Japanese Red Cross Medical Center Hospital, Tokyo, between August 2000 and September 2004. They were retrospectively evaluated for the risk factors of FN by applying Wilcoxon's rank sum test. A scoring index was defined and the patients were classified into high- and low-risk groups before evaluation. The following nine risk factors, which may significantly influence the relationship between the time required for defervescence and the duration of neutropenia - age; hematological diseases; the leukocyte count during the febrile period; the reduction in leukocyte count per day before the onset of FN; the prophylactic administration of antimycotic agents; sterilization of the intestinal tract; and urine albumin content, creatine level, and C-reactive protein (CRP) level - were expressed in points and their sum was termed risk points. The range of risk points was classified as 0-3 and 4-9. The time required for defervescence was 5.1 days when the risk points were in the range of 0-3 and 8.1 days when the points were in the range of 4-9. These figures were distributed normally and there was a significant difference between the two groups (P = 0.0016). FN associated with hematological malignancies is somewhat different from that related to other malignancies; it is therefore associated with unique risk factors. Most of the risk factors used in the present study can be evaluated objectively. At the onset of FN, they were expressed in points for evaluation. Further prospective studies are needed to determine whether these risk factors are suitable for use in actual cases.

Clinical and immunological evaluation of zoledronate-activated Vgamma9gammadelta T-cell-based immunotherapy for patients with multiple myeloma.

OBJECTIVE: To evaluate the potential anti-tumor activity of zoledronate-activated Vgamma9gammadelta T cells in vivo, we initiated a pilot study involving administration of zoledronate-activated Vgamma9gammadelta T lymphocyte-activated killer (LAK) cells to patients with multiple myeloma. MATERIALS AND METHODS: Subjects (n = 6) received four intravenous infusions at 2-week intervals of zoledronate-activated Vgamma9gammadelta T LAK cells generated from the culture of peripheral blood mononuclear cells (PBMCs) in the presence of zoledronate and interleukin-2. If the M-protein level in the patient's serum remained at baseline following four intravenous infusions, the patient underwent four more treatments at 4-week intervals. Subjects (n = 6) received a median of 0.99 x 10(9) Vgamma9gammadelta T LAK cells per infusion. RESULTS: No serious treatment-related adverse effects were observed during the study period. The percentage of Vgamma9gammadelta T cells in PBMCs and absolute numbers of Vgamma9gammadelta T cells in peripheral blood, particularly those of CD45RA(-)CD27(-) effector memory (TEM) Vgamma9gammadelta T-cell subsets increased in all the patients. Percentages of Vgamma9gammadelta T cells and TEM Vgamma9gammadelta T cells in bone marrow also increased in all the patients so far tested. M-protein levels in the serum remained at baseline in four of six patients and increased in two of six patients. Soluble major histocompatibility complex class I chain-related antigen A was detected only in the serum of patients whose M-protein level increased. CONCLUSION: Administration of zoledronate-activated Vgamma9gammadelta T LAK cells is a safe and promising immunotherapy approach for treatment of patients with multiple myeloma.

Angiogenic mediators of the angiopoietin system are highly expressed by CD10-positive lymphoma cells in angioimmunoblastic T-cell lymphoma.

Angioimmunoblastic T-cell lymphoma (AILT) is a malignant disease of peripheral T-cell origin that is characterized by a prominent proliferation of high endothelial venules in the lymph node. To investigate angiogenic mechanisms in AILT we measured the angiogenic mediator gene expression levels in the lymph nodes of 54 non-Hodgkin lymphoma patients, by immunostaining and quantitative reverse transcription polymerase chain reaction. Angiogenic mediators angiopoietin (Ang) 1 (ANGPT1), Ang2 (ANGPT2) and their receptor, Tie2 (TEK), vascular endothelial growth factor (VEGF; VEGFA) and its receptor, VEGFR2 (KDR), and hepatocyte growth factor (HGF) and its receptor, c-Met (MET) were all more highly expressed in AILT lymph nodes (16 cases) than in B-cell lymphomas (24 cases). Moreover, significantly higher Ang1 and Tie2 expression was detected in AILT cases with CD10-positive neoplastic T-cells by comparison with unspecified peripheral T-cell lymphoma (14 cases). Immunostaining confirmed the expression of Ang1 and VEGF by both neoplastic T-cells and follicular dendritic cells. These results suggest that the angiopoietin system may play an important role in the development of high vascularity in AILT lymph nodes. Consequently, as neoplastic T-cells and follicular dendritic cells are both increased in AILT and may represent an important source of angiogenic mediators, targeting these cells with anti-angiogenic strategies might represent a novel therapy for AILT.

Effect of liver and kidney function on migafungin disposition in patients with hematologic malignancies.

The plasma concentration of micafungin (MCFG) after intravenous infusion of MCFG at 150 or 300 mg/day over 1 hour to 49 patients with hematologic malignancies were determined, and the relationship between the plasma concentrations and the patients' laboratory parameters of liver and kidney function was analyzed. Plasma samples were obtained at the end of the initial administration of MCFG, 5 to 6 hours after the start of the initial administration, immediately before the second dosing, immediately before the fourth dosing, and the end of the fourth dosing. The plasma concentration of MCFG was measured by high performance liquid chromatography. The plasma concentration of MCFG was correlated with the doses of MCFG per kilogram body weight. The peak concentration after the initial administration was 3.8 times higher than the trough level after the initial administration. The steady-state peak and trough levels were 1.4-1.5 times higher than those after the initial administration. There was no correlation between the laboratory parameters of liver/kidney function and the dose-normalized plasma concentration of MCFG. These results suggest that MCFG can be administered safely to patients with liver or kidney dysfunction without adjusting the dose.

Follicular lymphoma with marked infiltration of eosinophils.

Eosinophilia and tissue infiltration by eosinophils are frequent findings in Hodgkin lymphoma, but they are extremely rare in B-cell lymphoma. Reported herein is a case of follicular lymphoma with extensive lymph node infiltration by eosinophils. The patient was a 71-year-old woman who had a mass in the vicinity of the pancreas found on routine ultrasonography. Subsequent CT indicated several enlarged abdominal lymph nodes, although superficial lymph nodes were not palpable. Two swollen mesenteric lymph nodes were excised to determine the cause of the lymphadenopathy. Histology indicated extensive infiltration of numerous eosinophils to the interfollicular area, especially in the dilated sinuses. The lymphoid follicles were relatively small, had inconspicuous germinal centers, and were scattered between dilated sinuses. Based on the histology, immunohistochemistry, and chromosomal abnormality, a diagnosis of follicular lymphoma was made. Expression of interleukin-3 (IL-3), IL-5, eotaxin, eotaxin-2, and eotaxin-3 was investigated on reverse transcription-polymerase chain reaction of the lymph node tissue, but none of the mRNA expression levels were elevated. This was a unique case of follicular lymphoma with extensive eosinophil infiltration, and to the best of the authors' knowledge this is the first such case ever reported.

Rapid induction of IAP family proteins and Smac/DIABLO expression after proapoptotic stimulation with doxorubicin in RPMI 8226 multiple myeloma cells.

We studied the expression dynamics of inhibitor of apoptosis protein (IAP) family members and Smac/DIABLO after treatment with doxorubicin in human multiple myeloma cell line RPMI 8226 and its doxorubicin-resistant variant DRR. Proapoptotic stimulation with doxorubicin rapidly induced the overexpression of mRNA as well as protein for IAPs in RPMI 8226 cells followed by a gradual decrease of their expression. Smac/DIABLO, which is known to neutralize IAPs, showed increased expression at the mRNA level after treatment; however, Western blot analysis revealed a slight decrease of the amount of protein. Immunoprecipitation analysis revealed the association of Smac/DIABLO with cIAP1 or XIAP after treatment with doxorubicin. In contrast to the RPMI 8226 cells, DRR cells did not undergo apoptosis in response to doxorubicin treatment. The DRR cells had higher levels of IAPs expression at the mRNA level and did not show a remarkable peak or decrease in the expression of mRNAs for cIAP1, cIAP2, XIAP, and survivin after treatment with doxorubicin. Furthermore, the expression of Smac/DIABLO mRNA was not up-regulated after treatment. These findings indicate that the suppression of IAPs expression by Smac/DIABLO shortly after proapoptotic stimulation might play a role in the mechanisms of apoptotic induction, and that the maintenance of high IAPs expression and low Smac/DIABLO expression after treatment might lead to the doxorubicin-resistance of multiple myeloma cells.