We used a degenerate RT-PCR screen and subsequent realtime 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 interrelated. 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.

HER-2/neu gene amplification and cell surface overexpression are important factors in breast cancer for prognosis and prediction of sensitivity to anti-HER-2/neu monoclonal antibody therapy. In lung cancer, the clinical significance of HER-2/neu expression is currently under evaluation. We investigated 238 non-small lung carcinomas for HER-2/neu protein overexpression by immunohistochemistry using the HercepTest. We found 2+ or 3+ overexpression in 39 patients (16%), including 35% in adenocarcinomas and 20% in large cell carcinomas, but only 1% of squamous cell carcinomas. Marked (3+) overexpression was uncommon (4%). The association between protein expression and gene copy number per cell, as determined by fluorescence in situ hybridisation assay, was investigated in 51 of these NSCLC tumours. Twenty-seven tumours (53%) were negative by both tests. Marked (3+) protein expression and gene amplification were present in only 4% of samples. In 11 tumours (21%), gene gain was accompanied by chromosomal aneusomy and did not result in high protein levels while in 7 (14%) the score 2+ was associated with maximum number of signals per cell 59. The prognostic implication of HER-2/neu protein expression was studied in 187 surgically resected tumours. No statistical difference in survival was observed comparing patients with positive (2+/3+) and negative tumours (0/1+), although 3+ patients showed a tendency to shorter survival. The therapeutic implications of protein expression and gene amplification in lung cancer need to be examined in prospective clinical trials.

We analyzed the TS-2 acute lymphoblastic leukemia (ALL) cell line that contains a t(1;19)(q23;p13.3) but lacks E2A-PBX1 fusion typically present in leukemias with this translocation. We found that the t(1;19) in TS-2 fuses the 19p13 gene DAZAP1 (Deleted in Azoospermia-Associated Protein 1) to the 1q23 gene MEF2D (Myocyte Enhancer Factor 2D), leading to expression of reciprocal in-frame DAZAP1/MEF2D and MEF2D/DAZAP1 transcripts. MEF2D is a member of the MEF2 family of DNA binding proteins that activate transcription of genes involved in control of muscle cell differentiation, and signaling pathways that mediate response to mitogenic signals and survival of neurons and T-lymphocytes. DAZAP1 is a novel RNA binding protein expressed most abundantly in the testis. We demonstrate that MEF2D/DAZAP1 binds avidly and specifically to DNA in a manner indistinguishable from that of native MEF2D and is a substantially more potent transcriptional activator than MEF2D. We also show that DAZAP1/MEF2D is a sequence-specific RNA-binding protein. MEF2D has been identified as a candidate oncogene in murine retroviral insertional mutagenesis studies. Our data implicate MEF2D in human cancer and suggest that MEF2D/DAZAP1 and/or DAZAP1/MEF2D contribute to leukemogenesis by altering signaling pathways normally regulated by wild-type MEF2D and DAZAP1.

A 5-year-old boy who initially presented with ALL and relapsed 4 months later with AML was found to have an add(19) in the leukemia cells. FISH revealed that the add(19) was really a cryptic t(l2;l9)(p13.3;p13.3) interrupting E2A (TCF3). Nucleotide sequences of cloned genomic fragments with the E2A rearrangements revealed that the der(12) contained E2A joined to an intron of the NOLI (p120) gene. Reverse transcriptase (RT)-PCR of patient lymphoblast RNA showed expression of in-frame fusion cDNAs consisting of most of NOL1 fused to the 3 0 portion of E2A that encoded part of the second transcriptional activation domain and the DNA binding and protein dimerization motifs. The reciprocal der(19) E2A genomic rearrangements included 5 0 regions of E2A joined to an intron of the ZNF384 (NMP4, CIZ) gene, located approximately 450 kb centromeric to NOL1 on chromosome 12. RT-PCR showed expression of in-frame E2A-ZNF384 fusion cDNAs. To our knowledge, this is the second report of a chromosome translocation in leukemia resulting in two different gene fusions. This is the first report of expression of E2A fusion protein that includes the DNA binding and protein dimerization domains due to a more proximal break in E2A compared to those described previously.

G- and C- banding patterns of seven species of the bat family Molossidae, Eumops glaucinus, E. perotis, Molossops abrasus, M. temminckii, Molossus ater, M. molossus, and Nyctinomops laticaudatus, were identified. Comparisons among the karyotypes of these species showed extensive homologies between E. perotis, M. ater, M. molossus, M. abrasus, and N. laticaudatus, demonstrating inter- and intrageneric conservatism, and a lesser degree of homologies in M. temminckii and E. glaucinus, reflecting intrageneric variation. Chromosomal variation was due to inversions, Robertsonian rearrangements, translocations, and variations in the location of constitutive heterochromatin and nucleolus organizer regions. The chromosome corresponding to No. 5 in the M. ater karyotype is discussed. We suggest that the Nyctinomops and Molossops karyotypes represent the primitive condition and that Molossus and Eumops have derived karyotypes.

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Case reports tively assigned to the 2q32-*qter region.8 The results of the assays in our proband and in the patient of Turleau et at2 confirm this localisation. In the latter, no position effect, which would tend to give an activity level lower than expected for a trisomic subject, could be shown. This was also the case for esterase D in a patient of Mohandas et al,9 who was the carrier of a de novo unbalanced t(X;13)(q27;ql2). References de Grouchy J, Turleau C. Atlas des maladies chromosomiques. 2nd ed. Paris: Expansion Scientifique Franqaise, 1982.

Aldehyde oxidase (AOX) is a member of the xanthine oxidase (XO) family of molybdenum hydroxylase, iron-sulfur flavoproteins and is involved in the metabolism of a wide range of native and xenobiotic compounds. The potentially toxic reduced oxygen intermediates (ROI), hydrogen peroxide (H2O2) and superoxide anion (O2(.-)), are generated when reduced AOX becomes oxidized by molecular oxygen, raising the possibility for involvement of AOX in pathophysiology. Indeed, ROI generation by AOX has been directly implicated in hepatic ethanol toxicity. A cDNA encoding human AOX has been cloned, sequenced, and identified as AOX1. AOX1 was proposed as a candidate for an autosomal recessive form of amyotrophic lateral sclerosis (ALS2) because a YAC carrying AOX1 was mapped to the ALS2 locus and was expressed in microglial cells of the spinal cord. As a source of H2O2, AOX could mediate motor neuron degeneration. To provide a basis for further analysis of AOX1 in pathophysiology, and to examine the relationship of the human AOX1 gene to the gene for human xanthine dehydrogenase (XDH), we have studied the chromosomal locus encoding AOX1 in humans. In the present communication, we have analyzed P1 artificial chromosomes containing AOX1. Our refined chromosomal mapping by FISH locates AOX1 very centromere proximal in the 2q33 region at 2q32.3-2q33.1. We present the first complete structural map of an AOX gene and provide direct evidence that human XDH and AOX1 are related by a gene duplication event. In addition, 1500 bp of upstream DNA containing the putative AOX1 promoter were sequenced and expressed. In contrast to the amino acid coding regions, AOX1 and XDH promoter sequences exhibit marked divergence that reflects the differential activation of these closely related genes. Evidence is presented that AOX may be polygenic in humans as it is in plants, Dipterans, and mice.