André Brizard

Quantitative HOX expression in chromosomally defined subsets of acute myelogenous leukemia.

We used a degenerate RT-PCR screen and subsequent real-time quantitative RT-PCR assays to examine the expression of HOX and TALE-family genes in 34 cases of chromosomally defined AML for which outcome data were available. AMLs with favorable cytogenetic features were associated with low overall HOX gene expression whereas poor prognostic cases had high levels. Characteristically, multiple HOXA family members including HOXA3–HOXA10 were jointly overexpressed in conjunction with HOXB3, HOXB6, MEIS1 and PBX3. Higher levels of expression were also observed in the FAB subtype, AML-M1. Spearmann correlation coefficients indicated that the expression levels for many of these genes were highly inter-related. While we did not detect any significant correlations between HOX expression and complete response rates or age in this limited set of patients, there was a significant correlation between event-free survival and HOXA7 with a trend toward significance for HoxA9, HoxA4 and HoxA5. While patients with elevated HOX expression did worse, there were notable exceptions. Thus, although HOX overexpression and clinical resistance to chemotherapy often coincide, they are not inextricably linked. Our results indicate that quantitative HOX analysis has the potential to add new information to the management of patients with AML, especially where characteristic chromosomal alterations are lacking.

Resistance in vitro to low-dose aspirin is associated with platelet PlA1(GP IIIa) polymorphism but not with C807T(GP Ia/IIa) and C-5T kozak (GP Ibα) polymorphisms

OBJECTIVES We investigated whether three platelet gene polymorphisms, Pl(A1/A2), C807T, and C-5T Kozak (encoding, respectively, for platelet membrane glycoproteins (GP) IIIa, GP Ia/IIa, GP Ibalpha), could contribute to the resistance to a low dose of aspirin (160 mg/day). BACKGROUND Aspirin antiplatelet effect is not uniform in all patients, and the mechanism by which some patients are in vitro resistant to aspirin remains to be determined. However, it has been suggested that polymorphisms of platelet membrane glycoproteins might contribute to aspirin resistance. METHODS Ninety-eight patients on aspirin (160 mg/day) for at least one month were enrolled. Aspirin resistance was measured by the platelet function analyzer (PFA)-100 analyzer; genotyping of the three polymorphisms was performed using a polymerase chain reaction-based restriction fragment-length polymorphism analysis. RESULTS Using a collagen/epinephrine-coated cartridge on the PFA-100, the prevalence of aspirin resistance was 29.6% (n = 29). Aspirin-resistant patients were significantly more often Pl(A1/A1) (86.2%; n = 25) than sensitive patients (59.4%; n = 41; p = 0.01). Of the 29 patients, 25 were reevaluated after having taken 300 mg/day aspirin for at least one month. Only 11 patients still have nonprolonged collagen epinephrine closure time, and these were all Pl(A1/A1). No relation was found between resistance status and C-5T Kozak or C807T genotypes. CONCLUSIONS Platelets homozygous for the Pl(A1) allele appear to be less sensitive to inhibitory action of low-dose aspirin. This differential sensitivity to aspirin may have potential clinical implications whereby specific antiplatelet therapy may be best tailored according to the patients Pl(A) genotype.

Indolent course as a relatively frequent presentation in T‐prolymphocytic leukaemia

T‐prolymphocytic leukaemia (T‐PLL) is a rare disorder with a poor outcome. Presentation features were studied in 78 T‐PLL cases. Although 53 patients (group A) presented with typical progressive disease including rapidly increasing leucocytosis, 25 patients (group B) experienced an initial indolent clinical course with stable moderate leucocytosis. The morphology and antigenic profile of abnormal cells were similar in both groups, except for a lower incidence of CD45RO+ CD45RA− pattern in group B. A high incidence of inv(14)(q11;q32), t(14;14)(q11;q32) and i(8)(q10) chromosomal abnormalities were found in both groups. After an initial indolent phase (median 33 months; 6–103 months), 16 group B patients progressed to an aggressive stage with clinical and laboratory features similar to group A. Moreover, median survival after progression was short in both groups. In conclusion, T‐PLL may start as an indolent disease similar to that reported in ataxia telangectasia. In this rare genetic disorder, some patients develop stable T‐cell clones which progress toward T‐PLL‐like leukaemia. Moreover, ATM gene mutations have been reported in T‐PLL. Thus, both diseases are likely to be closely related.

Trisomy 8q due to i(8q) or der(8) t(8;8) is a frequent lesion in T-prolymphocytic leukaemia: four new cases and a review of the literature.

Summary. Cytogenetic abnormalities found in four cases of T‐cell prolymphocytic leukaemia (T‐PLL) are described. An isochromosome 8q was found in three patients and a t(8;8) in one. In the four cases, karyotypes were complex and showed a high degree of instability. In addition, we reviewed 27 published cases of cytogenetically studied T‐PLL. On the whole, the most frequently recurring anomalies in T‐PLL are 14q lesions with nonrandom breakpoints, inversion (14)(q11q32) or tandem translocations (14;14) (not seen in any of our cases) and trisomy for 8q, mainly due to i(8q), found in more than 40% of patients each.

Heterogeneity of t(1;19)(q23;p13) acute leukaemias

The t(1; 19)(q23;p13) translocation occurs commonly in B‐lineage ALL. Previous reports have demonstrated a predominance of cases with expression of cytoplasmic Igμ (Cμ+), an FAB L1/L2 phenotype, a poor prognosis and expression of a fusion transcript involving the E2A and PBX1 genes in Cμ+ but not in Cμ‐ cases.

p190BCR-ABL rearrangement as a secondary change in a case of acute myelo-monocytic leukemia with inv(16)(p13q22)

The simultaneous occurrence of two specific primary chromosomal changes in hematological malignancies is rare. We report on a patient with acute myelo-monocytic leukemia and both inv(16)(p13q22) and t(9;22)(q34;q11) with a p190(BCR-ABL) rearrangement. The t(9;22)(q34;q11) translocation appears to be a secondary change. Similar secondary BCR-ABL rearrangements have already been described and, in most cases, the chimeric protein was of the p190(BCR-ABL) type as in our case. A complete remission was obtained by conventional chemotherapy followed with imatinib mesylate maintenance therapy. At relapse, the BCR-ABL transcripts were undetectable, which suggests that imatinib mesylate could be an effective adjuvant treatment in acute leukemia with a secondary t(9;22)(q34;q11).

Identification of several genes differentially expressed during progression of chronic myelogenous leukemia

The Bcr-Abl fusion protein plays a crucial role in the initiation and maintenance of chronic myelogenous leukemia (CML). However, additional events are necessary for the transition from the chronic phase to the terminal phase of the disease. To identify genes involved in the disease progression, we constructed a subtractive library from enriched K562 cell mRNA. We obtained 1084 cDNA clones. After a specific hybridization of these clones with a cDNA probe from either chronic phase or K562 cells, 43 clones which present a differential hybridization level have been selected. Among them, several clones corresponded to ribosomal protein genes showing an increased transcription level during the blast crisis. We observed variations in the expression of a cellular adhesion molecule, a laminin-binding protein. An increased transcription level of the MAZ gene has been shown in the terminal phase of the disease. This gene encodes a protein that regulates the transcription of myc.

Persistence of Transcriptionally Silent BCR-ABL Rearrangements in Chronic Myeloid Leukemia Patients in Sustained Complete Cytogenetic Remission

Persistence of BCR-ABL rearrangements was demonstrated by D-FISH technique in chronic myeloid leukemia (CML) patients in complete cytogenetic response (CCR) after allogeneic bone marrow transplantation (BMT) or interferon-α therapy (IFN-α). Samples from bone marrow aspkate or peripheral blood or both were analyzed by conventional cytogenetics, Southern blot, fluorescent interphase in situ hybridization (FISH), and quantitative reverse transcription polymerase chain reaction (Q-RT-PCR). In all patients, FISH detected 1% to 12% nuclei with a BCR-ABL fusion gene, whereas Q-RT-PCR were negative or weakly positive. Based on these results, we hypothesize that the BCR-ABL genomic rearrangement remains unexpressed in a small percentage of cells whatever the treatment (IFN-α or BMT), and this in spite of the negativity of the RT-PCR-based classical molecular remission criterion. These data corroborate those obtained by other investigators and point to the need for follow-up of CML patients in CCR over an extensive period, at the DNA level to evaluate the residual disease and at the RNA level (Q-RT-PCR) to estimate the risk of relapse and guide the therapeutic decision. Experimental models suggesting the persistence of positive BCR-ABL cells are discussed and tentative explanations of tumor “dormancy” are proposed.

Does BCR-ABL genomic rearrangement persist in CML patients in complete remission after interferon α therapy?

Cytogenetic, interphase fluorescent in situ hybridization (FISH) and RT-PCR methods were used to study minimal residual disease in peripheral blood stem cells collected for autografting in three chronic myeloid leukemia (CML) patients in sustained complete cytogenetic remission after treatment with interferon α (IFNα). Karyotypic analysis failed to reveal Ph-positive metaphases. FISH detected 9–16% nuclei with a BCR-ABL fusion gene, contrasting with RT-PCR, performed in two cases, which was negative in one case and weakly positive in the other. RT-PCR was also subsequently weakly positive in the third patient. This discrepancy suggests that the BCR-ABL genomic rearrangement persists unexpressed in quiescent cells. These preliminary results, which need to be confirmed in larger series, suggest that monitoring residual disease in CML should be performed both at DNA and RNA levels. Moreover, autografting following IFNα therapy should be considered with caution because of the persistence of the BCR-ABL genomic rearrangement in a sizeable proportion of the cells.

Recurrence of childhood acute lymphoblastic leukemia presenting as a tumor of the middle ear: a case report.

PURPOSE Extramedullary relapse of childhood acute lymphoblastic leukemia most commonly occurs in the central nervous system or in the testes. Otologic involvement is very rare and has only been reported as an autopsy finding. PATIENT AND METHODS We describe the case of a 5-year-old girl with CD10 positive acute lymphoblastic leukemia (ALL) who developed an isolated otologic relapse 18 months after the initial diagnosis of ALL. RESULTS This otologic relapse presented as an atypical otitis media related to a mass of the middle ear. The leukemic infiltration of the middle ear was demonstrated by histologic examination. A cytogenetic change characterized by the occurrence of t(1;19)(q23;p13) was observed in the leukemic cells from the middle ear, and the t(1;19) molecular fusion transcript E2A-PBX1 was detected in the bone marrow by polymerase chain reaction. CONCLUSION The ear is an exceedingly rare site of relapse in children with acute lymphoblastic leukemia. Molecular analysis demonstrates that such an extramedullary relapse can represent an early manifestation of systemic relapse.