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The FHIT tumor suppressor gene, which encompasses the fragile site FRA3B at 3p14.2, is altered frequently in many types of human cancers. To determine its importance as a prognostic marker in breast cancer, the expression of the FHIT protein was studied in a series of 452 breast carcinomas by using immunohistochemistry on sections of tissue microarrays. Three distinct levels of FHIT expression were observed: in 154 cases (34.1%) expression was unchanged as compared to normal level; in 78 (17.2%) no expression was found; in the remaining 220 cases (48.7%), expression was intermediate. Overall, two-thirds of the cases had abnormal levels of the protein. Absence of FHIT was significantly associated with a higher grade (p < 0.01) and absence of hormone receptors (p < 0.001). The patients were separated into Group I (153 node-negative good prognosis patients who did not receive adjuvant chemotherapy) and Group II (226 high-risk patients treated by adjuvant chemotherapy) according to the St.-Gallen conference consensus. The median follow-up was 48 months. Among Group I but not Group II patients, a multivariate analysis showed that FHIT expression was significantly associated with disease-free survival. The relative risk of recurrence for FHIT-negative Group I patients was 2.37 (1.21-4.64; p = 0.03). Thus, among the patients who present with tumors of apparent good prognosis, FHIT is an independent prognostic factor that distinguishes a subgroup of patients who could benefit from adjuvant treatment., (Copyright 2003 Wiley-Liss, Inc.)

We report here the sixth case of acute monoblastic leukemia associated with the inv(8)(p11q13) pericentric inversion. As seen in the previous cases, the inv(8)(p11q13) molecular characterization showed that the alteration results in a MOZ-NCOA2 gene fusion. The presence of erythrophagocytosis is a distinctive morphologic feature that is observed in all patients with MOZ alteration. However, the relative young age of the 6 patients (median: 23.5 years) and same sex (female) are the common characteristics that are only observed in the inv(8)-positive leukemia subgroup. In addition, we tested whether the presence of FLT3 internal duplications (ITD) are frequently found in malignant hemopathies with 8p11-12 rearrangements. We did not find any FLT3 ITD in any of the studied cases.

The 8p11-21 region is a frequent target of alterations in breast cancer and other carcinomas. We surveyed 34 breast tumor cell lines and 9 pancreatic cancer cell lines for alterations of this region by use of multicolor fluorescence in situ hybridization (M-FISH) and BAC-specific FISH. We describe a recurrent chromosome translocation breakpoint that targets the NRG1 gene on 8p12. NRG1 encodes growth factors of the neuregulin/heregulin-1 family that are ligands for tyrosine kinase receptors of the ERBB family. Breakpoints within the NRG1 gene were found in four of the breast tumor cell lines: ZR-75-1, in a dic(8;11); HCC1937, in a t(8;10)(p12;p12.1); SUM-52, in an hsr(8)(p12); UACC-812, in a t(3;8); and in two of the pancreatic cancer cell lines: PaTu I, in a der(8)t(4;8); and SUIT-2, in a del(8)(p). Mapping by two-color FISH showed that the breaks were scattered over 1.1 Mb within the NRG1 gene. It is already known that the MDA-MB-175 breast tumor cell line has a dic(8;11), with a breakpoint in NRG1 that fuses NRG1 to the DOC4 gene on 11q13. Thus, we have found a total of seven breakpoints, in two types of cancer cell lines, that target the NRG1 gene. This suggests that the NRG1 locus is a recurring target of translocations in carcinomas. PCR analysis of reverse-transcribed cell line RNAs revealed an extensive complexity of the NRG1 transcripts but failed to detect a consistent pattern of mRNA isoforms in the cell lines with NRG1 breakpoint., (Copyright 2003 Wiley-Liss, Inc.)

FGFR1, a transmembrane receptor tyrosine kinase for fibroblast growth factors, is constitutively activated by chromosomal translocations in an atypical stem-cell myeloproliferative disorder. The FGFR1 tyrosine domain is fused to dimerization domains encoded by 4 alternative genes: FOP at 6q27, CEP110 at 9q33, FIM/ZNF198 at 13q12, and BCR at 22q11. In this study, we report the molecular cloning of the t(8;19)(p12;q13.3), the fifth translocation associated with this syndrome. Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis and fluorescence in situ hybridization (FISH) demonstrated that the translocation resulted in a long terminal repeat of human endogenous retrovirus gene (HERV-K)/fibroblast growth factor receptor 1 (FGFR1) fusion transcript that incorporated 5' sequences from HERV-K fused in frame to 3' FGFR1 sequences encoding the kinase domain. RT-PCR detected only 1 of the 2 possible fusion transcripts, HERV-K/FGFR1.

All molecular alterations that lead to breast cancer are not precisely known. We are evaluating the frequency and consequences of reciprocal translocations in breast cancer. We surveyed 15 mammary cell lines by multicolor fluorescence in situ hybridization (M-FISH). We identified nine apparently reciprocal translocations. Using mBanding FISH and FISH with selected YAC clones, we identified the breakpoints for four of them, and cloned the t(3;20)(p14;p11) found in the BrCa-MZ-02 cell line. We found that the breakpoint targets the potential tumor-suppressor gene FHIT (fragile histidine triad) in the FRA3B region; it is accompanied by homozygous deletion of exon 5 of the gene and absence of functional FHIT and fusion transcripts, which leads to the loss of FHIT protein expression. Additional experiments using comparative genomic hybridization provided further information on the genomic context in which the t(3;20)(p14;p11) reciprocal translocation was found., (Copyright 2002 Wiley-Liss, Inc.)

Two distinct clinical syndromes have been associated with the p11.12 region of the short arm of chromosome 8: stem-cell myeloproliferative disorder (B-or T-cell lymphoblastic leukemia/lymphoma with myeloid hyperplasia and peripheral blood eosinophilia) and acute myeloid leukemia (myelomonocytic or monocytic with erythrophagocytosis). The FGFR1 and MOZ genes are rearranged in these diseases and encode one of the four fibroblast growth factor receptors and a member of a novel histone acetyltransferase family, respectively. The predicted fusion proteins that are putatively oncogenic - FOP-FGFR1, CEP110-FGFR1, and FIM-FGFR1 - and - MOZ-CBP, MOZ-p300, and MOZ-TIF2 - lead to tumorigenesis through distinct pathways. The constitutive kinase activity triggered by dimerization mediated by the protein-protein interaction motifs of the FGFR1 protein partner regardless of external stimuli and the delocalization of the fusion proteins compared to their normal counterparts may lead to tumorigenesis presumably by inducing inappropriate recruitment in the cytoplasm of signaling substrates. Currently, little is known about the precise role of MOZ in the regulation of gene transcription. However, all the aberrant proteins described to date retain the MOZ histone acetyltransferase domain fused to that of the transcription coactivators CBP, p300, and TIF2. The fusion of two acetyltransferases whose activity may be mistargetted or misregulated could be a critical event in leukemogenesis. The increasing number of translocations affecting FGFR1 and MOZ strongly suggest their involvement in oncogenic processes and point to these proteins as potential therapeutical targets.

Translocations affecting the chromosomal locus 8p12 are hallmarks of an atypical stem cell myeloproliferative disorder. These events disrupt the fibroblast growth factor receptor 1 (FGFR1) gene and fuse the FGFR1 C-terminus catalytic domain with unrelated proteins. Here, we report on the characterization of the 19q13.3 locus as the fifth FGFR1 chromosomal partner.

We report on the fusion of the monocytic leukemia zinc finger protein (MOZ) gene to the adenoviral E1A-associated protein p300 (p300) gene in acute monocytic leukemia M5 associated with a t(8;22)(p11;q13) translocation. We studied two patients with double-color fluorescence in situ hybridization (FISH) using the yeast artificial chromosome 176C9 and the bacterial artificial chromosome clone H59D10 specific to the MOZ and p300 genes, respectively. Both probes were split in the patients' chromosome metaphase cells, and the two derivative chromosomes were each labeled with both probes. We showed by Southern blot the rearrangement of the MOZ gene, and cloned the fusion transcripts in one patient carrying the t(8;22) by reverse transcription-polymerase chain reaction using MOZ- and p300-specific primers. Both fusion transcripts were expressed. This result defines a novel reciprocal translocation involving two acetyltransferases, MOZ and p300, resulting in an abnormal transcriptional co-activator that could play a critical role in leukemogenesis.

gamma-heregulin is a recently described novel isoform of the heregulin/neuregulin class of EGF-like ligands that bind to and activate receptors of the ErbB family. Deregulated signaling through the heregulin-ErbB pathway is thought to be implicated in the development of a subset of human breast cancers. gamma-heregulin has been found to be expressed in the culture supernatant of MDA-MB-175, a breast carcinoma cell line. gamma-heregulin is characterized by the presence of a large N-terminal peptide extension that is not found in other heregulin isoforms. Here we report that this unique N-terminal extension of gamma-heregulin is identical to the N-terminus of DOC4, a product of a recently identified CHOP-dependent stress-induced gene. Human DOC4 and the heregulin-encoding genes map to different chromosomes and the MDA-MB-175 cell line contains a chromosomal translocation that leads to the fusion of DOC4 and HGL, on chromosomes 11 and 8, respectively. Thus, gamma-heregulin is a product of a mutant fusion gene and not a bona fide normal isoform. We speculate that the mutation may be selected for by virtue of its ability to activate ErbB signaling through the production of an autocrine ligand.

We report on a novel chromosomal aberration, inv(8)(p11q24), in an M5 acute myeloid leukemia. We show by fluorescence in situ hybridization and Southern blot analyses that a t(8;16)(p11;p13) is masked by this inversion. The translocation targets the MOZ gene from the 8p11 and the CBP gene from the 16p13 chromosomal regions. The breakpoints occur in the MOZ region encoding the acidic domain and in the 5' end of the CBP gene. These results provide further evidence for the multiple contribution of both MOZ and CBP genes in acute leukemias. Genes Chromosomes Cancer 26:161-165, 1999., (Copyright 1999 Wiley-Liss, Inc.)

Several genes, most of them unknown, of the short arm of chromosome 8 are involved in malignant diseases. Numerous studies have implicated a portion of the 8p11-p21 region as the location of one or more tumor suppressor genes involved in a variety of human cancers, including breast cancer. We and others have reported linkage analyses suggesting the presence of a putative breast cancer susceptibility gene. Furthermore, several oncogenes of the 8p11-p12 region are involved in reciprocal translocations in myeloproliferative and myelodysplastic disorders and in amplification in breast cancer. To facilitate the analysis of the 8p11-p21 region and the cloning of candidate oncogenes and tumor suppressor genes, a high-resolution physical and transcriptional map was established with 39 yeast artificial chromosomes and 94 markers, including so-called sequence-tagged sites and expressed sequence-tagged sites derived from either known genes or expressed sequence tags corresponding to unidentified transcripts. In addition, four novel transcripts were identified and localized precisely within the map. This transcription map provides a detailed description of gene order for the 8p11-p21 region and will be helpful in the identification of candidate genes for diseases. From this basis, we refined the mapping of two types of molecular alterations that occur at 8p11-p21 in sporadic breast cancers, i.e., amplification and deletion.

Chromosome 8p11-12 is the site of a recurrent breakpoint in a myeloproliferative disorder that involves lymphoid (T- or B-cell), myeloid hyperplasia and eosinophilia, and evolves toward acute leukemia. This multilineage involvement suggests the malignant transformation of a primitive hematopoietic stem cell. In this disorder, the 8p11-12 region is associated with three different partners 6q27, 9q33, and 13q12. We describe here the molecular characterization of the t(8;13) translocation that involves the FGFR1 gene from 8p12, encoding a tyrosine kinase receptor for members of the fibroblast growth factor family, and a gene from 13q12, tentatively named FIM (Fused In Myeloproliferative disorders). FIM is related to DXS6673E, a candidate gene for X-linked mental retardation in Xq13.1; this defines a gene family involved in different human pathologies. The two reciprocal fusion transcripts, FIM/FGFR1 and FGFR1/FIM are expressed in the malignant cells. The FIM/FGFR1 fusion protein contains the FIM putative zinc finger motifs and the catalytic domain of FGFR1. We show that it has a constitutive tyrosine kinase activity.

A stem-cell myeloproliferative disorder involving T- and B-cell, and myeloid lineages, is associated with three different translocations with a breakpoint in region p11-12 of chromosome 8: t(6;8)(q27;p11), t(8;9)(p11;q33), and t(8;13)(p12;q12), respectively. Using fluorescence in situ hybridization (FISH), we have analysed blood cells from a series of five patients carrying these different translocations. We have identified cosmids from chromosome region 8p11-12 that span the breakpoint in all the cases. They are specific for the FCFR1 gene that encodes a receptor for members of the FGF family. The breakpoint was further detected by Southern and pulsed-field gel electrophoresis analyses with probes from the FGFR1 locus.

Using a series of yeast artificial chromosomes (YAC) from the Bp11-12 chromosome region, we have analyzed a t(8;22) translocation present in two patients suffering from acute leukemia by using fluorescence in situ hybridization (FISH). We have identified a YAC that spans the breakpoint in both cases.

Detailed physical maps of the human genome are important resources for the identification and isolation of disease genes and for studying the structure and function of the genome. To improve the definition of the 8p12-p21 chromosomal region, an integrated physical and genetic map was constructed extending from the genes. NEFL to FGFR1. The map comprises a series of contigs (the larger of these being around 9 Mb) of yeast artificial chromosomes (YACs) spanning the proximal region of deletion involved in a broad range of human cancers, including breast carcinomas, and in the Werner syndrome. In addition, losses of heterozygosity at 8p markers and linkage analysis of breast cancer families were also detailed. Finally, several genes potentially involved in 8p-associated diseases, namely GTF2E2, PPP2CB, and HGL, were precisely mapped within the YAC contigs. The reported map and contigs of YACs should facilitate the search for putative genes involved in sporadic and familial breast cancer as well as in the Werner syndrome.

Chromosomal region 8p11.2-p12 is consistently amplified in human breast cancer. We have constructed a 2.8 Mb YAC contig of this region, centered on the human Fibroblast Growth Factor Receptor 1 (FGFR1) locus and encompassing the Adrenergic beta 3 Receptor (ADRB3) locus. A smaller centromeric YAC contig spanning 1.4 Mb was also assembled, and included the Ankyrin 1 (ANK1) and Tissue-type Plasminogen Activator (PLAT) genes. Results from mapping of the contigs showed physical linkage of the ADRB3 and FGFR1 genes, which were colocalized within the same YAC clone and separated by about 900 kb, FGFR1 being in centromeric position. It also showed physical linkage of ANK1 and PLAT genes, which appear to be separated by a maximum of 700 kb. In parallel, several loci were mapped according to their amplification status in a large panel of breast tumor samples. The overall amplification pattern suggested a continuous amplicon with a core around FGFR1. Data from both the detailed physical map and the amplification status allowed to establish the following gene order, from telomere to centromere: ADRB3-D8S105-FGFR1-ANK1-PLAT-POLB. The precise localization and YAC cloning of the core of the amplicon will allow to isolate a putative oncogene involved in mammary carcinogenesis.

Two somatic cell hybrids containing the der(12) or the der(X) from a mesothelioma with a translocation t(X;12)(q22;p13) as the only chromosomal change were generated to characterize the region of 12p13 containing the translocation breakpoint. Fluorescence in situ hybridization analysis showed the breakpoint on chromosome 12 to occur between VWF and D12S158. On the linkage map developed by J. Weissenbach et al. (Nature, 1992, 359: 794-801), the breakpoints were located between D12S99 and D12S100 on chromosome 12 and between DXS1106 and DXS1001 on chromosome X. PCR analysis based on genomic sequences, with DNA from both somatic cell hybrids, enabled us to map CACNL1A1, FGF6, D12S370, D12S38OE, D12S381E, and D12S382E distally to the 12p13 breakpoint and to VWF.

An arrayed library of human heterogeneous nuclear complementary (hnc) DNA was constructed from a somatic cell hybrid (M28) containing an i(12p) marker as the sole human chromosome. Heterogeneous nuclear (hn) RNA of M28 was used to synthesize first-strand hncDNA with a primer (RT) containing a random hexanucleotide at its 3' end. Specific amplification of human sequences from this hncDNA was performed using Alu primers in combination with the RT primer. The products were directionally cloned and an arrayed library was constructed. Experiments indicated that all clones were derived from transcribed sequences. A number of randomly isolated clones were evaluated by Southern and Northern experiments, sequence analysis, and PCR. At least 80% of these clones were of human 12p origin. The number of independent clones in the library was estimated to be approximately 550. Using 60 hncDNA clones as probes, 6 showed positive signals on Northern blots. For 3 of these, the corresponding cDNAs were isolated: clone CD60A1 codes for the cation-dependent mannose 6-phosphate receptor, clone CC6 is a human homologue of the bovine 39-kDa nuclear-encoded NADH:ubiquinone oxidoreductase subunit, and CD18 belongs to the family of tumor necrosis factor receptor proteins. Southern experiments showed the 3 cDNAs to map to human chromosome 12p as expected. Taken together these results show that the generation of a hncDNA library is a useful tool for the isolation of unknown genes located on a human chromosome (fragment) present in a somatic cell hybrid.

Human epidermal growth factor receptor (EGFr) gene amplification, rearrangements and expression were studied in tumours of the human nervous system. EGFr gene amplification was studied in 46 brain tumours. Gene expression was analysed by northern blot in 37 tumours and binding of its protein to EGF in 27 tumours. The EGFr gene was simultaneously amplified (with arrangements in 12.5% of gliomas) and overexpressed in 53% (9/17) of malignant gliomas, but never in meningiomas. In five high grade gliomas, amplification was always associated with a high level of receptors. However, since high amounts of EGF receptors found in one glioma were not the result of gene amplification, several systems of deregulation in EGFr production may exist and could be located at translational and/or post-translational levels.