Isolation and characterization of a novel oncogene, amplified in liver cancer 1, within a commonly amplified region at 1q21 in hepatocellular carcinoma

Amplification of 1q21 is the most frequent genetic alteration in human hepatocellular carcinoma (HCC), being detected in 58%-78% of primary HCC cases by comparative genomic hybridization. Recently, we isolated a candidate oncogene, Amplified in Liver Cancer 1 (ALC1), from 1q21 by hybrid selection. Here we demonstrate that ALC1 was frequently amplified and overexpressed in HCC. ALC1-transfected cells possessed a strong oncogenic ability, increasing the colony formation in soft agar and increasing the tumorigenicity in nude mice, which could be effectively suppressed by small interfering RNA against ALC1. Functional studies showed that overexpression of ALC1 could promote G1/S phase transition and inhibit apoptosis. Molecular studies revealed that the oncogenic function of ALC1 might be associated with its roles in promoting cell proliferation by down-regulating p53 expression. Conclusion: These results suggest that ALC1 is the target oncogene within the 1q21 amplicon and plays a pivotal role in HCC pathogenesis.     

The gene for B7, a costimulatory signal for T-cell activation, maps to chromosomal region 3q13.3-3q21.

B7 is an activation antigen expressed on activated B cells and gamma-interferon-stimulated monocytes. The B7 antigen is the natural ligand for CD28 on T cells. After engagement of T-cell receptor with antigen in association with major histocompatibility complex class II, a second signal mediated through the binding of B7 to CD28 greatly upregulates the production of multiple lymphokines. We have now mapped the B7 gene to human chromosome 3 using the technique of polymerase chain reaction on a panel of hamster x human somatic cell hybrid DNAs. We have further localized the gene to 3q13.3-3q21 using in situ hybridization on human metaphase chromosomes. Trisomy of chromosome 3 is a recurrent chromosome change seen in various lymphomas and lymphoproliferative diseases, particularly diffuse, mixed, small, and large cell lymphomas, human T-cell lymphotropic virus type I-induced adult T-cell leukemia, and angioimmunoblastic lymphadenopathy. A number of chromosomal defects involving 3q21 have been described in acute myeloid leukemia and also in myelodysplastic and myeloproliferative syndromes. The mapping of B7 may permit further insight into disease states associated with aberrant lymphocyte activation and lymphokine synthesis.     

Translocations of 14q32 and deletions of 13q14 are common chromosomal abnormalities in systemic amyloidosis

Systemic monoclonal immunoglobulin light chain amyloidosis (AL) is associated with clonal plasma cell dyscrasias that are often subtle and non-proliferating. AL shares numerical chromosomal changes with multiple myeloma (MM) and monoclonal gammopathy of undetermined significance (MGUS). Illegitimate translocations involving the immunoglobulin heavy chain gene (IGH) at 14q32 and deletions of the long arm of chromosome 13, [del(13q)], commonly occur in MM, MGUS and plasma cell leukaemia. In AL IGH rearrangements have been identified but, to date, there are no reports of del(13q). In this study of 32 patients with AL, 24 with systemic and eight with localized disease, translocations involving IGH and del(13q) were found using dual-colour interphase fluorescence in situ hybridization (FISH). IGH translocations were observed in 11 patients (37% overall and in 46% with systemic disease), of which nine had the IGH/CCND1 fusion from t(11;14)(q13;q32). Two showed IGH translocations other than the t(11;14) or t(4;14)(p16;q32). In one of these patients a breakpoint within the constant region of IGH between Calpha1 and Calpha2 was indicated. In the second a deletion covering Calpha1 and Calpha2 accompanied the translocation. Ten patients (27% overall and 33% of those with systemic disease) showed del(13q). The gain or loss of IGH and CCND1 signals provided evidence of numerical chromosomal changes in three patients.     

The human homologue of the retroviral oncogene qin maps to chromosome 14q13.

Chromosomal mapping of the human QIN gene (renamed FKH2 by the Human Genome Organization Nomenclature Committee) was initially accomplished by correlation of the presence of the QIN locus with specific chromosome regions in a rodent-human hybrid panel. This analysis revealed that the human QIN gene maps to chromosome region 14q11.2-->14q32, between the TCR and IGH loci. Further analysis by fluorescence in situ hybridization techniques with a human QIN genomic clone refined the human QIN gene localization to 14q13.     

Concurrent chromosomal alterations at 3q27, 8q24 and 18q21 in B-cell lymphomas

Recurrent chromosomal translocations in malignant lymphomas most commonly involve 18q21(bcl-2), 8q24 (c-myc) and 3q27 (bcl-6), with an incidence of 27%, 11% and 6%, respectively. Individual cases concurrently harbouring two of these three rearrangements have been previously reported. This report describes four patients with cytogenetic alterations affecting all three loci, which was confirmed by molecular analysis in one case. Clinically, each patient had aggressive B-cell lymphoma with disseminated disease often involving the central nervous system, poor response to chemotherapy and short survival. Activation of c-myc in association with deregulation of bcl-2, bcl-6 or both confers high-grade disease with a poor prognosis.     

Brain-specific src oncogene mRNA mapped in rat brain by in situ hybridization.

Brain src protooncogene is expressed in two forms, one identical to message in other tissues, and one containing an 18-nucleotide insert specific to brain. We have mapped mRNA for the two forms of src in rat brain with selective antisense oligonucleotide probes to the brain (src+) and peripheral (src-) forms. Fetal rat src mRNA levels were much higher in the central nervous system than any peripheral organ. In adult brain, src+ mRNA level was highest in the internal granular layer of the olfactory bulb, pyramidal cells of the hippocampus, granule cells of the dentate gyrus, and cerebellar granule cells. src+ and src- levels were similar in hindbrain, but src+ levels were higher than those of src- in forebrain. These distributions suggest that src+ may play roles in a number of neural processes, possibly including neuronal plasticity.     

Double-hit lymphoma with t(8;14)(q24;q32) and t(12;14)(q24;q32) chromosomal translocations

A 50-year-old man presented with an ileocecal tumor and a large amount of ascites. Lymphoma cells obtained from the ascitic fluid were CD10(+), CD20(+), CD38(+), HLA-DR(+), BCL6(-), MUM1/IRF4(+), BCL2(+), and immunoglobulin μ/γ(+). The karyotype determined by G-banding and spectral karyotyping was 46, XY, der(3)t(1;3)(q12;p12), -4, +7, t(8;14)(q24;q32), t(12;14)(q24;q32), der(17)t(4;17)(q21;p11). Fluorescence in situ hybridization disclosed that 93% of interphase cells were positive for the c-MYC and immunoglobulin heavy chain gene fusion. The patient was treated with intensive chemo-immunotherapy, resulting in a complete response. The t(8;14)-t(12;14) double-hit may have generated molecular abnormalities analogous to those of a previously cloned three-way translocation t(8;12;14).     

Genomewide linkage analysis of the granulomatous mitsuda reaction implicates chromosomal regions 2q35 and 17q21

The Mitsuda reaction, a delayed granulomatous skin reaction elicited by the intradermal injection of heat-killed Mycobacterium leprae, is an in vivo test reflecting the ability to generate an immune granuloma after sensitization by diverse mycobacterial infections. Accumulating evidence for the genetic control of the Mitsuda reaction has been reported. We performed a genomewide linkage scan for the quantitative Mitsuda reaction in 19 large families from Vietnam with a history of leprosy (114 offspring). Suggestive linkage was found at chromosomal regions 2q35 (P = 9 x 10(-4) at the SLC11A1 locus) and 17q21-25 (P = 8 x 10(-4)). Interestingly, these 2 regions have been previously linked to mycobacterial infection and other granulomatous diseases.     

Myelodysplastic syndrome with chromosomal abnormality of t(11;21) (q23;q22)

A 33-year-old woman was hospitalized because of bleeding tendency. Hemoglobin was 10.7 g/dl, white blood cell 2,100/microliters and platelet 2.1 X 10(4)/microliters. Bone marrow showed marked dysplasia of trilineage blood cells. Atypical blasts and monocytoid cells accounted for 14.5% in the myelogram. Cytogenetic study of bone marrow cells revealed translocation with t(11;21) in all of 20 metaphasic cells analyzed by G-banding method. A diagnosis of RAEB was made. Familial survey revealed that her elder brother died of acute monocytic leukemia (AMoL). The patient received small dose therapy of Ara-C and BHAC-DMP therapy, but a remission was not obtained. The patient's general condition deteriorated with infection, bleeding tendency and chronic hepatitis due to transfusions, therefore we have followed up the patient with prednisolone and red blood cell transfusion. It has become evident that some types of acute leukemia with monocytic features have a cytogenetic change at 11 q 23. But it is rare that RAEB with increased monocytoid cells has a cytogenetic change at 11q23. In addition, the patient's elder brother died of AMoL. This case is important in relation to cytogenetic change at 11q23 and hematopoietic abnormalities.     

Marfan syndrome is closely linked to a marker on chromosome 15q1.5----q2.1.

Marfan syndrome is a systemic disorder of the connective tissue inherited as an autosomal dominant trait. The disorder imparts significant morbidity and mortality. The etiology of the disorder remains elusive. A recent study localized the gene for Marfan syndrome on chromosome 15. We present data showing that marker D15S48 is genetically linked to Marfan syndrome. Pairwise linkage analysis gave a maximum lod (logarithm of odds) score of Z = 11.78 at theta = 0.02. Furthermore our data suggest that the Marfan syndrome locus is possibly flanked on either side by D15S48 and D15S49.     

Human adhalin is alternatively spliced and the gene is located on chromosome 17q21.

Mutations in the dystrophin gene cause the X chromosome-linked, recessive Duchenne and Becker muscular dystrophies. Dystrophin, a large cytoskeletal protein, copurifies with a complex of dystrophin-associated proteins which serve to anchor dystrophin to the sarcolemma. One of these associated proteins, adhalin, has been implicated as a candidate for severe childhood autosomal recessive muscular dystrophy (SCARMD) due to absence of anti-adhalin staining in muscle biopsy samples taken from SCARMD patients. Furthermore, the Duchenne-like dystrophic phenotype seen in the SCARMD families was shown to be tightly linked to chromosome 13 markers. To determine the genetic mutation responsible for autosomal dystrophy, we characterized the human adhalin gene. Contrary to our expectation, human adhalin was mapped to chromosome 17q21, excluding adhalin as the gene causing chromosome 13-associated SCARMD. Additionally, a splice form of adhalin message was found that predicts a 35-kDa nontransmembrane adhalin. The expression of both adhalin splice forms is exclusively restricted to striated muscle, unlike other components of the dystrophin-glycoprotein complex.     

Minimal region of loss at 13q14 in B-cell chronic lymphocytic leukemia

Allelic loss at nonrandom chromosomal sites is thought to mark the position of tumor suppressor genes involved in the pathogenesis and progression of human malignancies. Solid tumors in particular have been found to harbor multiple genetic changes resulting in loss of function mutations. Tumor suppressor genes have also been found to be involved in the progression of lymphoid tumors. Previous reports have suggested the involvement of a tumor suppressor gene located on the long arm of chromosome 13, between the retinoblastoma (RB) and D13S25 loci, in the pathogenesis and or progression of more than 40% of B-cell chronic lymphocytic leukemia (B-CLL), a common lymphoid malignancy whose molecular etiology remains largely unknown. In the present study, we report the construction and characterization of a YAC contig spanning a region of approximately 3 cM between the RB gene and the D13S31 locus. We also screened 60 paired normal/tumor B-CLL samples for allelic loss on chromosome 13 with nine microsatellite markers located between RB and D13S25. This analysis has allowed us to narrow the smallest region of loss to a segment of 550 kb located between the 206XF12 and D13S25 markers.     

Refinement of lymphoma cytogenetics by the chromosome 18q21 major breakpoint region

A small (2.8-kilobase, kb) major breakpoint region localized to segment 18q21 rearranges in greater than 70% of t(14;18)(q32;q21) lymphomas. This rearrangement interrupts the Bcl-2 gene and introduces it into the Ig locus at 14q32. The rearrangement between the joining region (JH) of Ig on chromosome 14 and the 18q21 region creates a translocation- specific DNA rearrangement. We generated probes that distinguish the 14;18 juncture on the derivative (der) 14 and der (18) chromosomes, providing a molecular approach to t(14;18) identification. Approximately 60% of unselected follicular lymphomas, 20% of diffuse large cell lymphomas, and 50% of adult undifferentiated non-Burkitt lymphomas demonstrated 14;18 rearrangements within the major breakpoint region. Examination of DNA for 14;18 rearrangements resolved the identity of 14q+ chromosomes in two patient's cells that lacked an obvious reciprocal partner. Identification of the exact restriction fragments that mediate translocations complements routine cytogenetics. The detection of DNA rearrangements does not require dividing cells or the presence of an identifiable reciprocal partner and can detect clonal translocation rearrangements when the neoplastic cells are only a minority of all cells present.