A comprehensive karyotypic study on human hepatocellular carcinoma by spectral karyotyping

The current paucity of cytogenetic information on hepatocellular carcinoma (HCC) reflects the difficulties in culturing hepatocytes in vitro. Here, we report on the successful culture of 15 HCC cases. Chromosome aneuploidy ranging from a near-diploid to hyperhexaploid karyotype was found, but their complete karyotypic interpretations were hampered by the presence of many unidentifiable rearrangements. Spectral karyotyping (SKY) was used to elucidate structural changes in these HCC samples and 3 liver cancer cell lines (PLC/PRF/5, Hep3B, and HepG2). Frequent structural abnormalities were found on chromosomes 1 (13 of 15 cases; 3 of 3 cell lines), 8 (10 of 15 cases; 2 of 3 cell lines), 17 (9 of 15 cases; 3 of 3 cell lines), and 19 (9 of 15 cases; 1 of 3 cell lines). In particular, the chromosome regions 1p13-q21, 8p12-q21, 17p11-q12, 17q22, and 19p10-q13.1 were involved in multiple rearrangements. SKY analysis also suggested several previously undescribed breakpoints in HCC. These breakpoints, predominantly pericentromeric, clustered around the chromosome bands 2q33-q34, 3p13-q12, 4p14-q12, 5p10-q11, 7p12-q11, 10q10-q11, 11q10, 11q13-q21, 12q10-q13, 12q22-q23, 13q10-q14, 15q10, 16q10-q13, 18p11-q11, 20p11-q13.1, 21q10, and 22q10. When tumor sizes were compared, a significantly higher number of structural abnormalities was found in tumors larger than 4 cm (P =.007). Rearrangements such as t(1;8), t(1;11), t(1;19), and t(17;21) that were identified in both primary tumors and cell lines might represent markers that reflect proliferative advantages. Although SKY analysis did not indicate consistent translocations, it suggested nonrandom breakpoints, predominantly in the pericentromeric region, on a number of chromosomes. These breakpoint clusters may thus prove to be more important in the liver carcinogenesis and targets for further molecular investigations.     

Dendritic cells for NK/LAK activation: rationale for multicellular immunotherapy in neuroblastoma patients

Diffuse large B-cell lymphoma (DLBCL), a histologically well-defined subset of non-Hodgkin lymphoma, is clinically and genetically heterogenous. By G-banding, most cases showed complex hyperdiploid karyotypes and diverse cytogenetic abnormalities that included recurring and nonrecurring translocations, deletions, duplications, and marker chromosomes. While G-banding provided valuable leads to identification of specific rearrangements that enabled gene discovery and clinical correlations, many aberrations remained uncharacterized because of their complexity. The molecular cytogenetic technique spectral karyotyping (SKY), on the other hand, enables complete characterization of all aberrations in a tumor cell karyotype and, hence, precise quantitation of chromosome instability. We report here, for the first time, SKY analysis of a panel of 46 DLBCL cases previously analyzed by G-banding, ascertained at the Memorial Sloan-Kettering Cancer Center. This analysis provided a cytogenetic profile of DLBCL that was characterized by a higher level of instability, qualitatively as well as quantitatively, compared with G-banding. Thus, 551 breakpoints were detected by SKY, in contrast to the 295 by G-banding. Several new recurring breakpoints, translocations, and regions of gain and loss were identified, which included 13 breakpoints not previously identified by G-banding, 10 breakpoints that were underrepresented by G-banding, and 4 previously unrecognized translocations: der(14)t(3;14)(q21;q32), t(1;13)(p32;q14), t(1;7)(q21;q22), and der(6)t(6;8)(q11;q11). We identified new clinical associations involving recurring breakpoints detected by SKY. These studies emphasize the value of SKY analysis for redefinition of chromosomal instability in DLBCL to enhance gene discovery as well as clinical correlation analysis.     

Heterogeneity of breakpoints of 11q23 rearrangements in hematologic malignancies identified with fluorescence in situ hybridization

Twenty-four patients whose cells contained a variety of 11q23 rearrangements, including translocations, insertions, and an inversion, were studied using fluorescence in situ hybridization with cosmid, phage, and plasmid probes mapped to 11q22-24. In 17 patients, the breakpoints of the common 11q23 translocations involving chromosomes 4, 6, 9, and 19 as well as some uncommon translocations involving 3q23, 17q25, 10p11, and an insertion 10;11 were all located in the breakpoint cluster region of the MLL gene, regardless of age, phenotype of disease, or involvement of a third chromosome. The breakpoints in 11q23 in the other 7 patients with a t(7;11)(p15;q23), inv(11)(p11q23), t(4;11)(q23;q23), der(5)t(5;11)(q13;q23), ins(10;11)(p11;q23q24), t(11;14)(q23;q11), or t(11;18;11) (p15;q21;q23) were located either centromeric to CD3D or telomeric to THY1. Thus, although most 11q23 rearrangements, involve the same breakpoint cluster region of MLL, there is heterogeneity in the breakpoint in some of the rare rearrangements.     

Nonrandom chromosomal rearrangements of 14q32.3 and 19p13.3 and preferential deletion of 1p in 21 patients with multiple myeloma and plasma cell leukemia

Structural chromosomal abnormalities and their break-points were characterized in 17 patients with multiple myeloma (MM) and 4 with plasma cell leukemia by banding. Chromosome 14q32 translocations with a variety of partners were detected in 13 patients, and a variant translocation t(8;22)(q24.1;q11) was detected in 1. Three recurrent 14q32 translocations have been identified: t(6;14)(p21.1;q32.3) occurring in 3 cases, and t(11;14)(q13;q32.3) and t(14;18) (q32.3;q21.3) each occurring in 2 cases. Translocations t(1;14)(q21;q32.3), t(3;14)(p11;q32),t(7;14)(q11.2;q32.3), and t(11;14)(q23;q32.3) were found in each patient, whereas in the remaining 2 patients, partner chromosomes could not be determined. The band 19p13.3 was newly delineated as a recurrent breakpoint involved in translocations in MM. Chromosomes 1 and 6 were also commonly involved in structural abnormalities (14 and 10 patients, respectively), although no particular bands were noted. However, the short arm of chromosome 1 was preferentially involved in deletion, suggesting a certain antioncogene on 1p associated with the development of myeloma. In addition; fluorescence in situ hybridization was successfully applied to determine the nature of the structural abnormalities in a patient with t(8;22) translocation. The present findings suggest that there may be subsets of 14q32 translocations specific to MM.     

Multicolour spectral karyotyping identifies new translocations and a recurring pathway for chromosome loss in multiple myeloma

Multicolour spectral karyotyping (SKY) was performed on primary tumour specimens from 100 patients with multiple myeloma (MM) that showed complex clonal chromosome aberrations not fully characterized by G-banding. In this study, SKY was able to identify or revise translocations with breakpoints involving 14q32, 11q13 or 8q24 in 32 patients (32%). Five new recurring translocations were identified, two of which involved chromosome 22. A subtle reciprocal translocation t(14;22) (q32;q11 approximately 12) was identified using SKY in two patients and a second, much larger, translocation t(11;22)(q13;q13) was identified using G-banding in three patients. A third new translocation was identified in two patients using SKY and G-banding as der(7)t(7;7)(p15 approximately 22;q22 approximately 32). Twenty-three patients (23%) showed the loss of 8p by whole-arm translocations with different whole-arm donor chromosomes. Among this group, two new recurring whole-arm translocations involving the centromeric breakpoint 8q10 were identified as der(8;20)(q10;q10) and der(8;18) (q10;q10) in three patients each. In addition, a novel pattern of three-way translocations involving the clonal evolution of the t(8;22)(q24;q11) by the subsequent loss of 8p by whole-arm translocations was found in three patients. The chromosome instability identified here demonstrates that the loss of 8p can occur by multiple whole-arm translocations, indicating a new pathway for the loss of a specific chromosome region in MM.     

Cytogenetic and molecular delineation of a region of chromosome 3q commonly gained in marginal zone B-cell lymphoma

BACKGROUND AND OBJECTIVES: Whole or partial trisomy 3 represents the most recurrent chromosomal abnormality occurring in marginal zone B-cell lymphoma (MZBCL), a distinct subtype of B-cell non-Hodgkin's lymphoma (NHL). By conventional cytogenetic analysis, unbalanced translocations involving chromosome 3 and leading to a partial trisomy 3q were identified in a series of 14 MZBCL patients. Fluorescent in situ hybridization (FISH) experiments were then performed to characterize the breakpoints further and to delineate the extent of the 3q gained region more accurately. DESIGN AND METHODS: We studied 14 cases of MZBCL combining cytogenetics and FISH techniques using specific probes for the long arm of chromosome 3, including the chromosome 3 a satellite probe, a representative panel of yeast artificial chromosome (YAC) clones mapping the chromosomal 3q region (3q11.2 to 3q23) and the chromosome 3 subtelomeric (3q29) probe. RESULTS: In the 14 cases, additional chromosome 3q material was found to be involved in different unbalanced translocations with chromosomes 1, 6, 7, 8, 11, 13, 14, 15, 17, 19 and 21, leading to a derivative chromosome. None of the chromosomal abnormality juxtaposed the 3q regions with the heavy and/or light k and l immunoglobulin gene loci. Eight different breakpoints distributed between the 3q11.2 and the 3q13.32 regions were identified and a common 3q13.32 3q29 overrepresented region was delineated. INTERPRETATION AND CONCLUSIONS: These results suggest that this critical region may be of importance in the pathogenesis of MZBCL and support the hypothesis that a gene dosage effect rather than a specific gene disruption may be involved in the development of this disease.     

Interphase and metaphase detection of the breakpoint of 14q32 translocations in B-cell malignancies by double-color fluorescence in situ hybridization

The breakpoint of 14q32 translocations found in B-cell malignancies was delineated specifically in both metaphase spreads and interphase nuclei by double-color fluorescence in situ hybridization (FISH) using bacteriophage clones containing the human immunoglobulin gamma chain gene locus (Ig gamma) and a cosmid clone, CY24-68, containing VH segments. CY24-68 is more telomeric than Ig gamma, separated by approximately 1 megabase (Mb). FISH studies were performed on four patients with non-Hodgkin's lymphoma (NHL), one with acute lymphoblastic leukemia (ALL), one with plasma cell leukemia (PCL), and three cell lines. In each patient with t(8;14), t(14;18), and t(3;14), the signal of Ig gamma gene was observed on der(14) and that of CY24-68 at respective partner sites of these translocations, 8q24.1, 18q21.3, and 3q27. Interphase nuclei with a signal of Ig gamma clearly separated from that of CY24-68 were more frequently encountered in all of the patients (45% to 74%) than those in normal controls (4% to 5%). Even in cases where only interphase nuclei were available for FISH studies, 14q32 translocations are detected as shown in two patients each with NHL and t(11;14)-carrying PCL. In two cell lines, HS-1 derived from ALL carrying t(8;14) and FR4 derived from a plasmacytoma carrying a complex form of t(8;14), the signal of Ig gamma was observed at the breakpoint region 8q24.1 of the der(8) in addition to the der(14), indicating that translocation event occurred within the Ig gamma locus. Intense Ig gamma signal was found at the breakpoint region on the der(14)t(11;14) in HBL-2 derived from NHL, indicating amplification of the Ig gamma gene, and presumably the resultant chimeric DNA between Ig gamma and DNA sequences at 11q13. The present approach allowed us to unequivocally detect tumor-specific breakpoints of 14q32 translocations. Furthermore, interphase FISH provides a rapid diagnostic procedure to detect 14q32 translocations in B-cell malignancies.     

Immunoglobulin light chain gene translocations in non-Hodgkin's lymphoma as assessed by fluorescence in situ hybridisation

In non-Hodgkin's lymphoma (NHL), the majority of translocations involve the immunoglobulin heavy chain gene ( IGH ) locus, while a few involve the immunoglobulin light chain gene ( IGL ) locus, consisting of the kappa light chain gene ( IGκ ) and the lambda light chain gene ( IGλ ). Although many reports have dealt with the translocation and/or amplification of IGH in NHL, only a few have identified IGL translocations. To identify cytogenetic abnormalities and the partner chromosomes of IGL translocations in NHL, we performed dual-colour fluorescence in situ hybridisation (DC-FISH) and spectral karyotyping (SKY) in seven NHL cell lines and 40 patients with NHL. We detected IGL translocations in two cell lines and nine patients: four patients with diffuse large B-cell lymphoma, three with follicular lymphoma, one with extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue and one with mantle cell lymphoma. Five distinct partners of IGλ translocation were identified by SKY analysis: 3q27 in three patients, and 1p13, 6p25, 17p11.2 and 17q21 in one patient each. Three cases featured double translocations of IGH and IGL. These findings warrant the identification of novel genes 1p13, 6p25, 17p11.2 and 17q21.     

Identification of numerical and structural chromosome aberrations in 15 high hyperdiploid childhood acute lymphoblastic leukemias using spectral karyotyping

Abstract: Spectral karyotyping (SKY) on metaphase spreads from 15 high hyperdiploid (>51 chromosomes) childhood acute lymphoblastic leukemias (ALL), which typically display a poor chromosome morphology, was performed in order to investigate the pattern of numerical abnormalities, reveal the chromosomal origin of marker chromosomes, and identify translocations and other interchromosomal rearrangements not detected by G‐banding analysis. In all cases the numerical changes could be fully characterized, and a non‐random pattern of chromosomal gain was identified, with chromosomes X, 21, 14, 17, 6, 18, 4, and 10 being most frequently gained. The numerical changes had been partly misinterpreted in 12 of the 15 ALL patients using G‐banding, and the present study hence emphasizes the importance of SKY in identifying such anomalies, some of which, i.e. +4 and +10, have been suggested to be prognostically important. The chromosomal origin of all marker chromosomes and of seven structural rearrangements, one of which was the prognostically important Philadelphia chromosome, could be identified. Five rearrangements [der( 1 )t(1;14)(q32;q21), der( 2 )t(2;8)(q36;?), der( 3 )t(2;3)(q21;?), der( 8 )t(8;14)(?;?), and t(9;21)(q12;q22)] have previously not been reported in ALL, emphasizing the value of SKY in identifying novel chromosomal rearrangements.     

The t(8;14)(q24.1;q32) and its variant translocations: A study of 34 cases

BackgroundThe t(8;14)(q24.1;q32) and its variants – the t(2;8)(p12;q24.1) and t(8;22)(q24.1;q11.2) are associated with B-cell neoplasia and result in MYC/immunoglobulin (IG) gene rearrangement.Patients and methodsWe correlated the cytogenetic, molecular and clinico-pathological findings of patients with 8q24 translocations seen in the Department of Haematology, Christian Medical College, Vellore, from January 2003 to December 2015.ResultsThere were 34 patients with 8q24 translocations (31, ALL and three myeloma). The t(8;14) was seen in 25 patients, t(8;22) in seven and t(2;8) in two. The salient findings were as follows: 85% males; 79% adults, median age 37 years; L3 morphology in 61%; mature B immunophenotype in 77%; extra-medullary disease in 41%; additional abnormalities in 28 (85%), notably, structural abnormalities of chromosome 1q (41%) and 13q (9%) and monosomy 13 (15%); complex karyotypes in 68%.There were two double-hit lymphoma/leukemia, one with a t(14;18)(q32;q21) and the other with a t(3;14)(q27;q11.2), associated with nodal high grade B cell lymphoma and dermal leukemic infiltrates respectively.Only 13 samples were processed for DNA PCR and all these samples were positive for MYC-IgH (c-gamma type) rearrangement. Only in one patient, in addition to c-gamma, c-alpha rearrangement was also detected.ConclusionThe frequency (1.7%) and distribution of these translocations in our series and the association with 1q and 13q abnormalities is similar to the literature. Trisomies 7 and 12 were seen in less than 10% of our patients.     

Interphase FISH screening for the LCR-mediated common rearrangement of isochromosome 17q in primary myelofibrosis

Non-allelic homologous recombination (NAHR) between low-copy repeats (LCRs) has been implicated recently in somatic rearrangements including isochromosome i(17q), which is associated with hematologic malignancies as well as solid tumors. In hematological malignancies, the most common i(17q) breakpoint results from LCR-mediated NAHR, which creates a dicentric chromosome, idic(17)(p11.2). We report an elderly patient who presented with primary myelofibrosis (MF) with myeloid metaplasia (MMM), associated with idic(17)(p11.2) as the sole chromosomal abnormality, making this the first idic(17)(p11.2) myeloproliferative case reported in which the breakpoints are mapped to the breakpoint cluster region in proximal 17p. The rearrangement breakpoint maps to the previously defined LCR cluster, further suggesting that the genomic architecture of proximal 17p may be responsible for the formation of the majority of i(17q) cases. We describe our development of a rapid screening test using interphase FISH to detect idic(17)(p11.2), discuss the potential prognostic value of this molecular diagnostic test, and examine the relevance of LCR-mediated NAHR to common rearrangements in neoplasms.     

Chromosome 11q23 translocations in both infant and adult acute leukemias are detected by in situ hybridization with a yeast artificial chromosome.

The yeast artificial chromosome (YAC-13HH4), which spans a 440-kb region of DNA just distal to the CD3 locus on chromosome 11 at band q23, has been used to characterize a range of chromosomal translocations in acute leukemias from both adults and infants. In situ hybridization was performed on metaphase cells from bone marrow of 17 leukemias and two cell lines with a variety of chromosome 11q23 abnormalities. It was established that in infant leukemias the translocations t(11;19), t(4;11), and t(5;11) had occurred in the region defined by YAC 13HH4. Additionally, the translocations t(4;11), t(6;11), t(9;11), t(X;11), and t(10;11) in other leukemias were found to disrupt the same region of chromosome 11q23, although an exception was found in one t(6;11) translocation for which the breakpoint was distal to the YAC. One patient had a t(9;11) translocation in a therapy-related leukemia, suggesting that this class of etoposide-related malignancy has similar breakpoints to those occurring in de novo leukemias. An example of a lymphoma-derived translocation t(4;11) was shown to involve a deletion of the region defined by YAC 13HH4. A leukemia with a deletion on chromosome 11 (q23-q25) was also studied and it was shown that the YAC sequence was unaffected. It was concluded that, with a few exceptions, the translocations at 11q23 in a wide range of acute infant and adult leukemias occur in a common region and may result from a common underlying mechanism.     

Direct visualization of dispersed 11q13 chromosomal translocations in mantle cell lymphoma by multicolor DNA fiber fluorescence in situ hybridization

Several hematologic malignancies are associated with specific chromosomal translocations. Because of the dispersed distribution, chromosomal breakpoints may be difficult to detect using molecular techniques. We present a new application of a recently developed method, DNA fiber fluorescence in situ hybridization (fiber FISH), which allows direct visualization and mapping of chromosomal breakpoints. We tested this method for detection of the t(11;14)(q13;q32) translocation in mantle cell lymphoma. In DNA fiber FISH, a series of fluorochrome-labeled DNA probes covering several hundreds of kilobasepairs is hybridized to linear DNA molecules (or fibers) prepared from frozen tissue or intact cells. By using alternate fluorescent colors, a potential breakpoint region is stained in a color barcode pattern. Breaks in this region will split the barcode in two complementary parts, from which the breakpoint position can be derived. We used a 250-kb barcode covering the BCL-1 locus to detect 11q13 breakpoints in 20 well-characterized mantle cell lymphomas. A t(11;14) was shown by cohybridization of these probes with probes for the Ig heavy chain locus at 14q32. In 18 of 20 mantle cell lymphomas, a breakpoint within the 11q13/BCL-1 barcode was shown by the presence of multiple, complementary translocation products. Fusion of 11q13 and 14q32 sequences on single fibers indicating t(11;14)(q13;q32) was found in all 18 breakpoint-positive mantle cell lymphomas. In one additional case, fusion of an intact 11q13 barcode with 14q32 sequences indicated a breakpoint 100 kb centromeric of the major translocation cluster of BCL-1. Within the 120-kb region of BCL-1, breakpoints were widely scattered. This explains why, so far, a BCL-1 breakpoint had been detected by Southern blot analysis in only 10 of 19 cases. DNA fiber FISH analysis showed a t(11;14) in 95% of mantle cell lymphoma. The results indicate that DNA fiber FISH is a rapid, simple, and equally powerful method for detection of clustered and dispersed translocation breakpoints.     

The (4;11)(q21;q23) chromosome translocations in acute leukemias involve the VDJ recombinase.

Chromosomal region 11q23 is frequently rearranged in acute lymphocytic leukemias (ALLs) and in acute myeloid leukemias (AMLs), mostly in reciprocal exchanges with various translocation partners. The most common of these translocations is t(4;11)(q21;q23). It is present in approximately 10% of ALL patients, most frequently in very young children. We have recently cloned a region of chromosome 11, the ALL-1 locus, found to be rearranged in malignant cells from patients with the t(4;11), t(9;11), t(11;19), t(1;11), t(6;11), t(10;11), and del(11q23) chromosomal abnormalities. Here we report the cloning and characterization of chromosomal breakpoints from leukemic cells with t(4;11) aberrations. The breakpoints cluster in regions of 7-8 kilobases on both chromosomes 4 and 11. The presence of heptamer- and nonamer-like sequences at the sites of breakage suggests that the VDJ recombinase utilized for immunoglobulin gene rearrangement is also directly involved in these translocations. We also show that leukemic cells with t(4;11) express altered RNAs transcribed from the derivative chromosomes 11 and 4.     

Variability of 11q23 rearrangements in hematopoietic cell lines identified with fluorescence in situ hybridization

We mapped and ordered 17 cosmid, phage, and plasmid clones to chromosome 11, bands q22-q24, using fluorescence in situ hybridization (FISH). We then analyzed four hematopoietic cell lines with 11q23 rearrangements, Karpas 45, SUP-T13, RC-K8, and Karpas 422, using these probes. The studies showed that the translocation breakpoints of the Karpas 45 and SUP-T13 cell lines, which were derived from T-cell malignancies, were located in the same breakpoint cluster region of the MLL gene as the RS4; 11 cell line and patients with the t(9;11), t(11;19), and t(6;11) described previously. We confirmed that the translocation breakpoint of the RC-K8 cell line was located telomeric to the MLL gene, and found that the derivative 11 chromosome of the Karpas 422 cell line, which had been thought to contain a t(4;11) (q21;q23), was in fact formed through a deletion and an inverted tandem repeat of part of 11q.     

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.     

Acute lymphoblastic leukemias with deletion of 11q23 or a novel inversion (11)(p13q23) lack MLL gene rearrangements and have favorable clinical features

Balanced translocations affecting the 11q23 region are among the most frequent chromosomal abnormalities in childhood acute lymphoblastic leukemia (ALL), comprising 5% to 6%. These cases consistently have a rearranged MLL gene and are associated with high-risk presenting features, hyperleukocytosis and younger age, and a poor treatment outcome. To assess the clinical and biologic significance of 11q23- associated structural chromosomal abnormalities other than translocations, we studied 17 cases of childhood ALL [14 with del(11)(q23) and 3 with inv(11)(p12q23)] that were identified among 785 cases with successful chromosome analysis. In contrast to reported cases with 11q23 and MLL gene rearrangement, our series was characterized by relatively low leukocyte counts (median, 15.1 x 10(9)/L), expression of CD10 antigen but not myeloid-associated CD15 and CDw65 antigens, a relatively high frequency of T-cell immunophenotypes, and a generally favorable prognosis. All 13 cases with interpretable molecular analysis lacked MLL gene rearrangements. We suggest that most cases with deletions or inversions affecting the 11q23 region represent clinically and biologically different entities as compared with those defined by 11q23 translocation.     

Novel recurrent genetic imbalances in human hepatocellular carcinoma cell lines identified by comparative genomic hybridization

To search for recurrent and specific genomic alterations in human hepatocellular carcinoma (HCC), we examined 18 cell lines by comparative genomic hybridization (CGH), a molecular cytogenetic approach that allows positional identification of gains and losses of DNA sequences of the entire tumor genome. We report here a distinct pattern of multiple recurrent DNA copy-number gains and losses that include alterations frequently seen in other neoplasias as well as changes potentially specific for HCC. The most frequent gains were localized on 1p34.3-35, 1p33-34.1, 1q21-23, 1q31-32, 6p11-12, 7p21, 7q11.2, 8q24.1-24.2, 11q11-13, 12q11-13, 12q23, 17q11. 2-21, 17q23-24, and 20p11.1-q13.2. Recurrent losses were mapped on 3p12-14, 3q25, 4p12-14, 4q13-34, 5q21, 6q25-26, 8p11.2-23, 9p12-24, 11q23-24, 13q12-33, 14q12-13, 15q25-26, 18q11.2-22.2, and 21q21-22. Seventeen genomic imbalances are novel in HCC, thus extending significantly the map of genetic changes and providing a starting point for the isolation of new genes relevant in pathogenesis of liver neoplasia, as well as providing molecular probes for both diagnosis and monitoring treatment of the disease.