Natasa Colovic

Importance of early detection and follow-up of FLT3 mutations in patients with acute myeloid leukemia

Mutations in the fms-like tyrosine kinase 3 (FLT3) gene, such as internal tandem duplication (FLT3/ITD) in the juxtamembrane domain and point mutations in the tyrosine kinase domain, are the most common abnormalities in acute myeloid leukemia (AML). FLT3/ITD and FLT3/D835 mutations were analyzed in 113 Serbian adult AML patients using polymerase chain reaction. Twenty patients were found to be FLT3/ITD positive (17.7%). The mutations occurred most frequently in M5 and M0 subtypes of AML. They were mainly associated with the normal karyotype. All patients harboring FLT3/ITD had a higher number of white blood cells than patients without it (p = 0.027). FLT3/ITD mutations were associated with lower complete remission (CR) rate (χ2 = 5.706; p = 0.017) and shorter overall survival (OS; Log rank = 8.76; p = 0.0031). As for disease-free survival, the difference between FLT3/ITD-positive and FLT3/ITD-negative patients was not statistically significant (Log rank = 0.78; p = 0.3764). In multivariate analysis, the presence of FLT3/ITD mutations was the most significant prognostic factor for both OS and CR rate (p = 0.0287; relative risk = 1.73; 95% CI = 1.06–2.82). However, in the group of patients with the intermediate-risk karyotype, the mere presence of FLT3/ITD was not associated with inferior clinical outcome. FLT3/D835 point mutation was found in four patients (3.5%) only. Follow-up of the FLT3/ITD-positive patients revealed stability of this mutation during the course of the disease. However, changes in the pattern of FLT3/D835 mutations in initial and relapsed AML were observed. Our results indicate an association of FLT3/ITD with the adverse outcome in AML patients treated with standard induction chemotherapy. Because FLT3/ITD mutation is a target for specific therapeutic inhibition, its early detection could be helpful in clinical practice.

Functional analysis of the role of the TPMT gene promoter VNTR polymorphism in TPMT gene transcription

AIMS Thiopurine S-methyltransferase (TPMT) activity is polymorphic, and a trimodal distribution has been demonstrated in Caucasians (low, intermediate and high methylator groups). The TPMT gene promoter contains a variable number of three GC-rich tandem repeats, namely A, B and C, ranging from three to nine in length in a A(n)B(m)C architecture. MATERIALS & METHODS Here, we investigated the influence of number and type of TPMT gene promoter tandem repeats on human TPMT gene transcription in K562 cells transiently transfected with reporter constructs bearing various variable number of tandem repeats (VNTR) and addressed the interaction of transcription factor binding to the VNTRs by electrophoretic mobility shift assays. RESULTS We found that the distribution patterns of VNTR alleles do not significantly differ among acute lymphoblastic leukemia patients, acute myeloid leukemia patients and normal individuals. We also demonstrated that the A repeat has a negative effect in TPMT gene transcription and that a positive regulatory element, identified immediately upstream to the VNTR region of the TPMT gene promoter, is indispensable for TPMT gene transcription. Our electrophoretic mobility shift assay analysis indicated that the Sp1 and Sp3 transcription factors bind to the VNTR repeats. CONCLUSION Overall, our data underline that both the number and type of VNTRs, as well as the upstream regulatory region of the TPMT gene promoter, determine the overall level of TPMT gene transcription. It remains to be seen whether these VNTRs can be employed as pharmacogenetic markers to individualize thiopurine therapy.

More than a third of non-gastric malt lymphomas are disseminated at diagnosis: a single center survey

Mucosa‐associated lymphoid tissue (MALT) lymphomas are extranodal B‐cell tumors that generally follow an indolent course. The gastrointestinal tract is the most common site of MALT lymphoma, comprising 50% of all cases. The tissue lesions are often localized, have high therapeutic response rates with late relapses with a long overall survival (OS). The patients with non‐gastric lesions may follow a different clinical course and many of them present with disseminated disease. This study reports a series of 51 patients with non‐gastric MALT lymphoma. Twenty patients (39.2%) presented with disseminated disease, seven (13.7%) patients had two MALT mucosal sites involved and eight (15.7%) had involvement of three or more mucosal sites. At presentation, 17 (33.3%) patients had the lymph node and 12 (23.5%) the bone marrow involvement. Following various combinations of treatment, complete remission was achieved in 40 (81.6%), and partial remission in three of the 49 treated patients with no difference in response rates between different disease stages. Relapse occurred in 12/43 (27.9%) patients among whom eight (18.6%) recurred in the presenting organ system. Five patients (9.8%) died because of a rapid disease progression after a median follow‐up of 56 months; two patients with primary lung lesions, 1 patient with secondary intestinal disease, and 2 patients suffered transformation to diffuse large B‐cell lymphoma. No significant difference in survival was found between localized and disseminated disease (log rank 0.05, df = 1, P = 0.81). A patient age ≥ 60 yr at diagnosis and presentation with the nodal disease were found to be statistically significant negative prognostic factors (P < 0.05). Median OS was not reached after 145 months of follow‐up, with the estimated OS being 88% at 2 yr, and 78% at 5 yr.

Outcomes of primary thyroid non-Hodgkin's lymphoma: a series of nine consecutive cases.

Primary non-Hodgkin’s lymphoma (NHL) of the thyroid gland is a rare disease with an incidence of 0.5 per 100,000 population. Stages IE and IIE thyroid NHL have been traditionally treated by surgical resection; however, modern treatment consists of chemotherapy and local radiotherapy, and surgery is often reserved for tissue diagnosis and relief of airway compression. We retrospectively reviewed the management and outcomes of nine consecutive patients with thyroid NHL, eight females and one male (median age 63 yr, range 34-71 yr) treated between 1994 and 1999. Five patients had disease stage IE and 4 stage IIE. Median follow-up was 72 mo. Pathohistology and immunohistochemistry identified two patients with mucosa-associated lymphoid tissue (MALT), three follicular center cell lymphoma (FCC), two patients large B-cell lymphoma (BLCL), one a marginal zone lymphoma (MZL), and one patient a peripheral T-cell lymphoma (PTCL). Total thyroidectomy was performed in three patients and subtotal thyroidectomy in four. One (MALT) patient underwent surgery alone; three patients surgery, radiotherapy, and chemotherapy (two FCC, one PTCL); three patients surgery and chemotherapy (one MALT, one FCC, one LBCL); and two chemotherapy alone (one LBCL, one MZL). Median survival was 79 mo (range 13–124 mo). The PTCL patient, a 34-yr-old man, died from disseminated disease at 13 mo despite secondary chemotherapy, and one LBCL patient with extensively invasive local disease died from stroke 17 mo after diagnosis. The remaining seven patients remain in remission with no local or systemic relapse at a mean of 86 mo. With appropriate therapy primary thyroid NHL has a favorable course; however, prognosis depends on the histology, local spread, and the stage of the disease at presentation, as well as the patient’s performance status. Surgery in combination with chemotherapy and/or radiotherapy is still warranted for intermediate and high-grade thyroid NHLs, with over 77% of patients achieving long-term remission. Peripheral T-cell lymphoma carries a poor prognosis.

Indolent course of the cutaneous Hodgkin's disease

Abstract:  Skin involvement in Hodgkins disease (HD) is most often a secondary phenomenon representing a rare, late manifestation of dissemination of the disease heralding a grave prognosis. Primary cutaneous HD is very unusual, being reported in 0.5–3.4% of all patients. Based on the introduction of immunohistochemistry for better detection and classification, we report a case with an ostensibly isolated primary cutaneous HD who developed multiple cutaneous lesions 5 years before enlargement of the lymph node involved during relapse. Pathohistology of skin lesions and the involved lymph node indeed showed the same subtype (mixed cellularity) of HD characterized by the presence of CD15+, CD30+, CD45RO– cell‐surface markers and by the presence of Epstein–Barr virus+ marker‐analyzed immunohistochemistry.

Pretreatment risk factors and importance of comorbidity for overall survival, complete remission, and early death in patients with acute myeloid leukemia

Abstract The objective of this single-center study was to determine the pretreatment risk factors and influence of comorbidity on outcome in patients with acute myeloid leukemia (AML). The research involved 145 patients with AML during a 58-month follow-up period. The results suggest that the most significant predictor of poor overall survival (OS) is an adverse karyotype (P = 0.007), while for poor rate of complete remission (CR) it is age ≥55 years, and for early death the most significant predictor is comorbidity, as scored by the Hematopoetic Cell Transplantation Comorbidity Index (HCT-CI), P = 0.001. When we divided the patients into two groups: aged ≥55 years and aged <55 years, these predictors differed. In the group aged ≥55 years the most significant predictor of OS (P = 0.013) and for early death (P = 0.003) was HCT-CI (P = 0.013), while in the younger group it was karyotype (P < 0.001). The most significant predictor of CR in the elderly was increased serum lactate dehydrogenase (LDH) level (P = 0.045). In the younger patients, the most significant predictor of CR was leukocytosis (P = 0.001) and for early death it was infection as the comorbidity (P = 0.007). We point out the importance of comorbidity for OS and early death, as well as the impact of infection in patients with AML.

Thrombotic events in acute promyelocytic leukemia

INTRODUCTION Thrombotic events (TE) appear to be more common in acute promyelocytic leukemia (APL) than in other acute leukemias, with reported prevalence ranging from 2 to 10-15%. MATERIALS AND METHODS We retrospectively analyzed the data on TE appearance in 63 APL patients. RESULTS TE occured in 13 (20.6%) cases, four arterial (6.3%) and nine venous (14.3%). TE were more frequently diagnosed after initiation of weekly D-dimer monitoring (7 TE during 20 months vs 6 during 76 months, P=0.032). Patients with and without venous thrombosis were significantly different regarding female/male ratio (P=0.046), PT (P=0.022), aPTT (P=0.044), ISTH DIC score (P=0.001), bcr3 (P=0.02) and FLT3-ITD (P=0.028) mutation. The most significant risk factor for venous TE occurrence in multivariate analysis was FLT3-ITD mutation (P=0.034). PAI-1 4G/4G polymorphism was five times more frequent in patients with venous TE than without it (P=0.05). Regarding risk factors for arterial TE we failed to identify any. CONCLUSIONS We have demonstrated that APL-related TE rate is higher than previously reported and that weekly D-dimer monitoring might help to identify patients with silent thrombosis. Moreover, our study suggests a possible relationship between venous TE occurrence and several laboratory findings (PT, aPTT, ISTH DIC score, bcr3 isoform, FLT3-ITD mutation and PAI 4G/4G). Prophylactic use of heparin might be considered in patients with ISTH DIC score<5, bcr3 isoform, FLT3-ITD mutation and PAI 4G/4G.

Expression of Bcl2L12 in chronic lymphocytic leukemia patients: association with clinical and molecular prognostic markers

Dysregulation of apoptosis is a distinctive feature of chronic lymphocytic leukemia (CLL), although a unique mechanism underlying apoptosis resistance of CLL B lymphocytes has not been identified yet. Aberrant expression as well as genetic and epigenetic alterations of numerous genes involved in different pathways of apoptosis regulation has been described in CLL. Here, we report the expression analysis of Bcl2L12 (Bcl2-like 12), a novel apoptotic gene belonging to Bcl2 family, in 58 Serbian CLL patients. Quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR) analysis revealed a significant overexpression of Bcl2L12 mRNA in CLL samples compared to non-leukemic samples, implying its role in the pathogenesis of the disease. Receiver operating characteristic (ROC) analysis showed that Bcl2L12 expression efficiently discriminates CLL cases from healthy controls. However, relatively homogenous Bcl2L12 mRNA expression among patients did not reflect their clinical characteristics (with the exception of lactate dehydrogenase status and time from diagnosis to treatment) and failed to show association with the most informative prognostic markers, namely the mutational status of rearranged immunoglobulin heavy chain variable region genes, CD38 and lipoprotein lipase gene (LPL) expression.

Mycophenolate mophetil therapy for chronic immune thrombocytopenic purpura resistant to steroids, immunosuppressants, and/or splenectomy in adults

Treatment options are limited in patients with chronic immune thrombocytopenic purpura (ITP) which has been unresponsive to corticosteroids and/or splenectomy. Mycophenolate mophetil (MMF) is effective in many autoimmune disorders including severe and refractory ITP through its targeting of T-cell and B-cell lymphocytes. We report on the efficacy of MMF (1.5–2 g/day) in 16 adults with severe steroid-resistant ITP. MMF was administered for at least 12 weeks (median 37 weeks, range 14–64 weeks). Patients comprised of 10 females and six males, with median pre-treatment platelet counts of 8 × 109/L, median age of 55 years, median ITP duration of 58 months and a median of four prior treatments (range 3–8); nine had been previously splenectomized. Eleven patients (69%) responded after 12 weeks of MMF: 6 (55%) achieving complete remission (CR) and five (45%) achieved partial remission (PR). MMF therapeutic responses were better in those patients who had had fewer prior treatments (p < 0.05), and were independent of patient age, sex, disease duration, and splenectomy status (p > 0.05). Five of the 11 responders (45%; 3CR/2PR) had sustained remissions; however, six responders (55%; 3CR/3PR) relapsed after median of 14 weeks (range 9–20). Three of the six relapsing patients responded to MMF reinstitution achieving stabile PRs; three were left untreated as none had further bleeding and their platelets remained at “safe” levels (median 30 × 109/L). The MMF treatment was well tolerated; one heavily pretreated patient developed a bronchopneumonia and a second had an episode of diarrhea. MMF used as a second-line agent can produce a sustained response in severe ITP which has been unresponsive to steroid and/or splenectomy without major toxicity.

Immunochemotherapy for Bcl-2 and MUM-negative aggressive primary cutaneous B-cell non-Hodgkin’s lymphoma

The case of a 44-year-old man with a primary cutaneous large B-cell non-Hodgkin’s lymphoma of the scalp is reported. His mother died of gastric lymphoma and his sib brother is in a 20-year remission of T-cell lymphoma. The patient presented with a 16-year history of occipital and parietal alopecia and a recently worsening scalp rash. The histopathology and immunohistochemistry performed in April 2006 indicated a bcl-6+, MUM− and bcl-2−, primary cutaneous follicle center B-cell non-Hodgkin’s lymphoma, with an aggressive transformation to a diffuse large B-cell lymphoma. Bone marrow biopsy and CT chest, abdomen, and pelvis were negative for systemic lymphoma. The patient had an excellent clinical and histological resolution following 8 cycles of rituximab and CHOP protocol immunochemotherapy, and remains in complete remission until now. The protracted indolent phase of the disease, the familial history of lymphoma, the histological aggressive features and the patient’s excellent response to immunochemotherapy all contribute to a very unusual manifestation of this disease.