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From www.bloodjournal.org by guest on August 3, 2017. For personal use only. Direct Sequence Analysis of the 14q+ and 18q- Chromosome Junctions in Follicular Lymphoma By Finbarr Cotter, Christopher Price, Emanuele Zucca, and Bryan D. Young Although the t(l4;18) chromosome translocation has been demonstrated to be a highly consistent feature of follicular lymphomas, the underlying mechanism generating this fusion has remained uncertain. To examine this question further, a polymerase chain reaction strategy has been devised to permit the amplification and direct sequencing of the resultant 1 4 q i and 18q- reciprocal junctions. Direct sequence analysis of amplified 14q+ junctions established that 7 of 11 tumors contained a bcl-2 (mbr) sequence fused to an immunoglobulinJ, region (five were J, and two were J6).One of these junctions had an unusual configuration with the bcl-2 and J, sequences separated by a recognizable D, region. This finding suggests that at least some of the junctional sequences, previously thought of as N insertions, may be fragments of unrecognizedD, regions. It was also possible to amplify and sequence 18q- junctions using a primer based on the D, recombination signal sequences. Several 18q- junctions were shown to consist of D,lbcl-2 (either mbr or mcr) fusions. In two tumors the 14q and 18q - junctions were fully sequenced, and it was demonstrated that the bcl-2 sequence was conserved during mbr and mcr translocations. This contrasts with previousanalysesthat demonstrated either loss or duplication of several bases at the breakpoints in the bcl-2 gene. 0 1990 by The American Society of Hematology. + A MATERIALS AND METHODS PPROXIMATELY 85% of follicular lymphomas and Enzymatic amplification. DNA was extracted as previously 30% of diffuse large cell lymphomas have been demondescribedI4from 11 patients with histologically proven centroblastic/ strated to carry the t( 14;18)(q32.3;q21.3) chromosomal centrocytic follicular lymphoma. Enzymatic amplication was pertranslocation by both cytogenetic and molecular techniques.’,2 formed by the PCR procedure of Saiki et all5 using Thermus The breakpoints on chromosome 18 occur a t two sites, aquaticus (Taq) DNA polymerase and an automated Perkin-Elmer approximately 20 kilobases (kb) apart, within or near to a DNA Thermal Cycler (Cetus, Emeryville, CA). The final reaction transcriptional unit called the bcl-2 gene.2-6Approximately volume included 1 pg of tumor DNA, oligonucleotide primers (1 60% of the breakpoints occur within 150 base pairs (bp) mmol/L) (Boehringer Mannheim, FRG), 1.5 U of Taq DNA known as the “major breakpoint region” (mbr) in a 3’ polymerase (Amplitaq-Cetus),and gelatin (0.01% wt/vol) in 100 r L untranslated region of the bcl-2 A further 25% have of Taq buffer (50 mmol/L KC1, 10 mmol/L Tris-C1 pH8.3, 1.5 mmol/L MgCl,). Amplification of the mbr-J, junctions on chromobreakpoints at a site 20 kb 3’ to the mbr sequence in a region some 14q+ was performed with primers BCl and JH1 and the called the “minor cluster region” (mcr)2,and these translocaD,-mbr junctions on chromosome 18q- with primers DHI and BC2 tions occur within 500 bp of each other, some clustering (see Table 1). The mcr-J, junctions on chromosome 14q+ were within 3 bp on chromosome 18.’ On chromosome 14, the amplified with primers BC5 and JH1 and the D,-mcr junctions on breakpoints occur in the joining (J,) region of the immunochromosome 18q- with primers DHI and BC6. An initial denaturglobulin (Ig) heavy chain gene.4-6It has been postulated that ing step of 10 minutes at 94OC was followed by 30 cycles of 15 the translocation occurs as an error during VDJ joining at a seconds at 55OC (annealling), 1 minute at 7OoC(extension), and 30 time when terminal deoxynucleotidyl transferase is a ~ t i v e . ~ ’ ~seconds at 94OC (denaturing). The final extension period was At the junction on chromosome 14q+ short segments of lengthened to 10 minutes. Taq polymerase (Cetus), 1.5 U was added to the reaction after the initial denaturing step. Aliquots (10 pL) unidentifiable nucleotides, up to 24 in length have been from the reaction mixture were analyzed by electrophoresis in a 2% observed and postulated to represent “N” insertions noragarose gel in Tris borate electrophoresis (TBE) buffer and stained mally found at the VD and DJ junctions after IgH with ethidium bromide. In the few 18q- chromosomal breakpoints Direct sequence analysis. Direct nucleotide sequence analysis ~tudied,’.’~ it appears that Ig heavy chain diversity regions by the dideoxy chain termination method16 was performed on PCR (DH) are joined to the bcl-2 gene with loss of the 5’ J, region, products. DNA from the reaction mixture was purified using a suggesting a deletion between D, and J, in t(14;18) transloSephedex G50 column followed by ethanol precipitation, freeze cation in lymphomas.’ The translocation results in a hybrid drying, and resuspension in distilled water. Sequencing was perbcl-2/IgH transcript, but a normal bcl-2 protein, as the coding region appears to be structurally unaltered. However, the quantity of protein is increased within the cells containFrom the Imperial Cancer Research Fund, Medical Oncology ing the t( 14;18) translocation.”,’2 Unit, St Bartholomew’s Hospital, London, UK; and Medical OncolThe clustering of the majority of breakpoints on bcl-2 ogy Department, Ospedale San Giovanni. Bellinrona. Switzerland. facilitates the use of the polymerase chain reaction (PCR) Submitted November 20,1989; accepted March 6,1990. Supported by a grant f r o m the Caroline Lawson Trust f o r for amplification and analysis of the t ( 14;18) breakpoints. Children’s Cancer Research. Bcl-2 oligonucleotide primers (either mbrI3 or mcr’) flanking Address reprint requests to Finbarr E. Cotter. MD. ICRF the translocation have been used, with a consensus J, Medical Oncology Unit, Si.Bartholomew’s Hospital, London ECI sequence found at the 3’ end of each J, exon, to amplify the UK. 14q+ junctions. We have extended this approach to the The publication costs of this article were defrayed in part by page 18q - junctions using a primer based on part of the recombicharge payment. This article must therefore be hereby marked nation signal sequences known to flank germline D, se“advertisement” in accordance with 18 U.S.C. section 1734 solely to quences. Thus, it was possible to sequence junctions proindicate thisfact. duced by translocations in either the mbr or mcr regions in a 0 1990 by The American Society of Hematology. series of follicular lymphomas. 0006-4971/90/7601-0022$3.00/0 I Blood, Vol 76, No 1 (July 1). 1990: pp 131-135 131 From www.bloodjournal.org by guest on August 3, 2017. For personal use only. 132 COlTER ET AL Table 1. Position, Sequence. and Use of Synthetic Oligonucleotidesfor Analysis of t(14;18) Junctions Orientation Name Sequence Use Position (strand) JH 1 DH 1 BC 1 BC2 BC3 BC4 BC5 ( M C 1 2 ) 5'ACCTGAGGAGACGGTGACC-3' 5'-GTGAGGTCTGTGTCACTGTG-3' 5'-CCllTAGAGAGAGlTGCTlTACGT-3' 5'-ATAlTCCATAl-fCATCACmGAG-3' 5'-CACAGACCCACCCAGAGCCC-3' 5'-GTCTGATCAlTCTGlTCCCTG-3' 5'-GATGGCmGCTGAGAGGTAT-3' PCR PCR PCR PCR Sequencing Sequencing PCR 3' J, consensus 5' flanking region in D, 5' of mbr in bcC2 gene 3' of mbr in bcC2 gene 5' of mbr in bcC2 gene 3' of mbr in bcC2 gene 5' of mcr in bcC2 gene - BC6 BC7 (MC7) BC8 5'-lTAlTGAGTGGTCClTCCTlTC-3' 5'-TCAGTCTCTGGGGAGGAGTGG-3' 5'-TCAlTCAGlTGAGTGCTGTG-3' PCR Sequencing Sequencing 3' of mcr in bc/-2 gene 5' of mcr in bcC2 gene 3' of mcr in bcC2 gene + + + + + - Oligonucleotides BC5 and BC7 correspond to M C 1 2 and M C 7 used by Ngan et aI.* The heptamer recombination signal is underlined in oligonucleotide DH 1 formed using bcl-2 internal oligonucleotides as sequencing primers (Table 1) with the modified T 7 D N A polymerase (Sequenase, USB, Cleveland, OH), a 5-minute labeling reaction at lS°C, and a 5-minute termination reaction at 3 7 T . The mbr-J, junctions were sequenced with kinase-labeled aliquots of primer BC3 and the D,-mbr junctions with primer BC4, the mcr-J, junctions with BC7, and the D,-mcr junctions with BC8. problematic, because in the few tumors a diversity region (D,) has been found fused to bcl-2 sequence. However, a common feature of diversity regions is that they are flanked by heptamer-nonamer recombination signal sequences. We have sought to use this feature to design an oligonucleotide (DH1) for amplification from the chromosome 14 side of the 18q- junction. The full set of primers is shown in Table 1. Analysis of mbr junctions in bcl-2. DNA was prepared from a series of 11 follicular lymphoma samples. Enzymatic amplification using primers BC1 and JH1 was performed on each DNA sample, and electrophoresis showed specific products from 7 of 11 samples (data not shown). Under the conditions of amplification, normal human DNA yielded no fragments. Direct sequence analysis using primer BC3 showed the structure of these products, and the results are summarized in Fig 1. In all cases a fusion was demonstrated between a bcl-2 sequence and members of the Ig heavy chain joining RESULTS The majority of breakpoints on chromosome 18 due to the t( 14;18) translocation have been shown to occur in either of two regions within the bcl-2 gene (ie, the mbr or mcr). The corresponding breakpoints on chromosome 14 have been shown to occur at or close to members of the J, joining region genes of the Ig heavy chain locus. The high degree of clustering of both breakpoints renders the 14q+ junctions suitable for PCR amplification using either mbrI3 or mcr' oligonucleotides in combination with a J, consensus oligonucleotide. Similar amplification of the 18q- junction is more Palien1 A BCL-2 ...= CCTTCAGGGTCTTCCTGAAATGCA 16 t ~ ~ ~. .G~TTdCTdCTdCTdCTdCGGTdTGGdCGTCTGGGGCCddGGCdCCdCGGTCdCcGTcTcCTCdGG ~. ~ = Patient B BCL-2 CTTCCTGAAATGCAGTGGTGCTTA . . . a a a g a c q t c c JS . . .CTAC~TCCdC€CCTGCCGCCA~GGAACCCTGGTCdCCGTCTCCTCdGG Patient D BCL-2 G C A G G A A A C C T G T G G T A T G A A G C C. J6 . . ~ . .TGGACATTCTGCCATTGTGATTdCTdCTdCTdCTdCGGTdTGGdCGTCTGGGGCCAAGGGdCCdCGGTCdCCGTCTCCTCdGG . Patient E BCL-2 ...t CCCAGAGCCCTCCTGCCCTCCT~C Pallent DH J6 T g a q t a q a i c a a ~ ~ ~ ~ t t~a ttt d~c q tc t ~ a c . ~. . tTdCTdCTdCTdCTdCGGTdTGGAcGTCTGGGGC~GGWLCCdCGGTCdCCGTCTCCTCdGG ~ ~ = t ~ ~ G BCL-2 TGGTATGAAGCCAGACCTCCCCGG 16 ...g g c t t a q c q q q q c c a t a a c cg g c a . . . CdCCTCTGGGCCCAACGWLCCdCGGTCdCCGTCTCCTCdGG Patient L BCL-2 CTGTGGTATGAAGCCAGACCTCCC 15 . . .999 . . .AACG1VLCCCT~TCdCCCTCTCCTCdGG Patient M BCL-2 J6 GAAATGCAGTGGTGCTTACGCTCC..99caqcaa..ATTdCTdCT~CTdCTdCGGTdTGGdCGTCTGGGGCCddGGGdCCdCGGTCdCCGTCTCCTCdG Fig 1. Sequences of the chromosome 14q+ junctions in seven follicular lymphomas. Bcl-2 sequence is shown in upper case and joining region sequence is in upper case italics, with the coding exons in bold type. Differences between the J, sequences and their germline equivalents are underlined. The intervening sequences between bcl-2 and J, are indicated in lower case. The part of the intervening sequence that is identical to a previously identified D, region is underlined (patient E). From www.bloodjournal.org by guest on August 3, 2017. For personal use only. 133 SEQUENCE ANALYSIS 1(14;18) IN FOLLICULAR LYMPHOMA t-CHROMOSOME14 CHROMOSOME18 + CCCCGGmCGGTATGGGGAG lTATCGTATATGACCCGTGGCATCTGA. CGGGGGCmCTCATGGCTGTCClTCAGGGTCTT Fig 2 . The sequence of a chromosome 18q- junction in a follicular lymphoma. The mbr region of bcl-2 is fused to a sequence containing a region of homology (underlined) to a previously cloned D, sequence." The vertical line indicatesthe junction between the two chromosomes. region exons (J,), confirming the presence of the t(14;18) translocation in these tumors. The breakpoint on bcl-2 fell within the range of previously determined7 breaks in the mbr region. There was a clear preponderance (5 of 7) for the J, member of the J, family. Most of the J, sequences had some single base differences when compared with their germline equivalents. This could be due to either polymorphic variation or somatic mutation, which is known to occur during D-J recombination. In contrast, the bcl-2 sequence showed no evidence of mutation. In every junction there was an intervening sequence between bcl-2 and J,, although in patient D this consisted of only a single base. In patient E there was a particularly large intervening sequence which, on further analysis, was found to contain a recognizable D, region (Fig 1). The D, (diversity) regions recombine with J, in normal Ig gene rearrangement; thus, this junction (bcl-2-DH-J,) could result from translocation after D,-J, recombination. Thus, this junction consisted of bcl-2 fused to D,, which in turn was fused to J,. None of the other intervening sequences had significant homology to each other or to any other known D, or putative N insertion sequences. The primer D H l , in combination with the bcl-2 primer BC2, was used for amplification of the reciprocal junctions on chromosome 18q-. Although, on electrophoresis, bands were obtained from tumor samples, direct sequencing was successful from only a proportion of tumors. Thus, these bands may represent spurious products, unrelated to the IgHlbcl-2 junction on chromosome 18. The sequence of an 18q- junction is shown in Fig 2, in which a putative D, region is fused to the mbr region of bcl-2. In the sample from patient B, direct sequencing also showed the structure of the 18q- junction, and this has been compared with the 14q+ and normal chromosome 18 sequence in the same tumor in Fig 3. It is clear that during breakage and rejoining, the bcl-2 gene has been conserved without any of the short duplications or deletions noted by others.'.'' Analysis of mcr junctions in bcl-2. A similar analysis was performed using oligonucleotide primers for the mcr region of bcl-2. In a particular patient it was possible to sequence both the 14q+ and 18q- junction, and the results are shown in Fig 4. The 14q+ junction is similar to those reported by other?, with mcr sequence fused to a member of the J, family. Because the junction is well within the J, exon, it is not possible to identify uniquely which J, gene is involved. There is very little (at most a single base) sequence that could be called an N-insertion, and the breakpoint in mcr is precisely at a position which has been broken in two previously analyzed tumors.' The sequence of the reciprocal 18q- junction is also shown in Fig 4, and it is clear, as in Fig 3, that there has been no net loss or gain of bcl-2 sequence. Furthermore, as with mbr translocations, this junction is composed of a D, sequence fused to bcl-2. DISCUSSION The use of the D,-based primer (DH1) offers a means to amplify and analyze rapidly a proportion of the 18qjunctions. As a means of detecting the presence of the t(14;18), it appears to be less efficient than the equivalent strategy for the 14q+ junctions. Because this approach requires the presence of the 5' recombination signals next to the junctional D, exon, lack of amplification may be due to removal of the 5' recombination signal sequence by a preceding V,-D, recombination. In addition, the D, primer includes part of the intervening sequence between the heptamer and nonamer, which will tend to be less conserved. Although these features may tend to reduce the proportion of tumors in which the 18q- junctions can be successfully amplified, it is possible that other strategies, such as the use of a V, consensus primerL7,might be successful. Previous studies have shown that the 14q+ junctions are often characterized by short stretches of unrecognizable sequences, which, because of their position adjacent to a joining region, have been thought of as N-insertions. However, there are several features of these sequences that question this interpretation. Firstly, these translocation Nregions tend to be longer than normal N-region sequences, which rarely exceed 10 bases and are usually shorter." Secondly, the normal N-regions are G C rich whereas translocation N-regions are less so.'* Finally, Ngan et ala noted that two different tumors had an identical stretch of 11 bases in JH D H Fig 3. The sequences of the reciprocal 14q+ and 18q- junctions found in patient B are compared with the germline mbr region of bcL2. Gaps in sequence have been introduced for clarity and the underlined region represents a previously unidentified D, region. The vertical line indicates the position of the breakpoint in the mbr region. From www.bloodjournal.org by guest on August 3, 2017. For personal use only. 134 COTTER ET AL JH 14q+ junction GERMLINE BCL2 (mcr) 18q- junction D H Fig 4. Comparison of the reciprocal 14q+ and 18q- sequences in a patient with a translocation breakpoint in the mcr region of bcl-2. The underlined region represents a previously unidentified D, region. The vertical line indicates the position of the breakpoint within the mcr region in bcl-2. their putative N-regions, and speculated that such regions could be derived instead from previously unrecognized D, sequences. The tumor from patient E (Fig 1) has been shown to contain a complete D, sequence within its putative N-region. This finding supports the idea that at least some of the putative N-regions could contain fragments of D, regions. Interestingly, this D, sequence is identical to one previously shown to be located 150 bases 5’ to a D, involved in a follicular lymphoma transl~cation.~ Comparison with this sequence indicates that the germline recombination signals are missing from the 5’ end of the D, sequence (Fig 1 ), suggesting that either the translocation has occurred as a mistake in V-D joining with a subsequent N insertion, or that V-D-J recombination had taken place before translocation. The former explanation has been invoked to explain a translocation in the Daudi Burkitt lymphoma cell line as a mistake in V-D joining with the D-J already rearranged.’’ The latter course of events has been proposed” to account for a t(8;22) translocation in Burkitt’s lymphoma in which the Ig X light chain complex was thought to be rearranged before translocation. The underlying mechanism that generates the t( 14;18) translocation has been the subject of some debate. It has been suggested that the translocation occurs as a result of mistakes in VDJ recombination. This is based on the presence of sequences on chromosome 18 close to some breakpoints, which bear a similarity to the heptamer-nonamer signal sequences mediating VDJ recombination.’ However, the homology is weak and breakpoints are not always associated with such sequences. Also, if this mechanism were operative the reciprocal set of recognition signals with a 23-bp spacer would be expected within mbr, and these have not been found.’ An alternative explanation for the breakage of bcl-2 that does not depend on the presence of heptamer-nonamer signal sequences has been proposed. Bakhshi et a17 analyzed the reciprocal junctions of a follicular lymphoma and noted a 3-bp duplication at the junction. It was proposed that this could be the result of a staggered double-stranded break of the type known to result in direct repeats flanking the insertion of foreign DNA. However, subsequent analysis of two tumors” has shown small deletions, rather than duplications, of bcl-2 sequence at junctions. Moreover, in our study both tumors analyzed showed conservation of bcl-2 sequence, and therefore the duplication of junctional bcl-2 sequence is not a general feature of the t(14;18) translocation. Interestingly, the breakpoint in mbr on chromosome 18 for patient B is at a location identical to that found in a tumor analyzed by Tsujimoto et a1” in which a deletion of 2bp had occurred. This effectively rules out the possibility that the gain or loss of bcl-2 sequence is, in some way, dependent on the position of the breakpoint. The analysis of the reciprocal junctions for the translocation in mcr (Fig 4) showed a similar structure to that found in mbr breakpoints. In particular, the fusion of a D, to mcr sequence forming the 18q- junction has the same configuration as that found in mbr translocations. This suggests that similar mechanisms are involved in mcr translocations. This breakpoint lies at exactly the position of two previously analyzed breaks in mcr8 which themselves were part of a tight cluster of five breaks within 4 bases of each other. An interesting feature of this cluster is that it is bounded by two direct repeats (CTGCAAAC) 7 bases apart. Although the underlying mechanism for the t( 14;18) translocation in follicular lymphoma remains unclear, similar factors appear to operate for breaks in both the mbr and mcr regions. Our sequence data suggest that, at least in some cases, it is possible that translocation has taken place after D-J rearrangement. ACKNOWLEDGMENT The authors gratefully acknowledge the advice of G . Phear in performing direct sequencing; the synthesis of oligonucleotides by I. Goldsmith; and the clinical support of T.A. Lister. REFERENCES 1. Yunis JJ, Oken MM, Kaplan ME, Ensrud KM, Howe RR, Theologides A: Distinctive chromosomal abnormalities in histologic subtypes of non-Hodgkin’s lymphomas. N Engl J Med 307:1231, 1982 2. Weiss LM, Warnke RA, Sklar J, Cleary ML: Molecular analysis of the t( 14;18) chromosomal translocation in malignant lymphomas. N Engl J Med 317:1185, 1987 3. Cleary ML, Sklar J: Nucleotide sequence of a t(14;18) chromosomal translocation breakpoint in follicular lymphoma and demonstration of a breakpoint cluster region near a transcriptionally active locus on chromosome 18. Proc Natl Acad Sci USA 82:7439, 1985 4. Cleary ML, Galili N, Sklar J: Detection of a second t(14;18) breakpoint cluster region in follicular lymphomas. J Exp Med 164:315, 1986 5. Bakhshi A, Jensen JP, Goldman P, Wright JJ, McBride OW, Epstein AL, Korsmeyer SJ: Cloning the chromosome breakpoint of t( 14;18) human lymphomas: Clustering around J, on chromosome 14 and near a transcriptional unit on 18. Cell 41:899, 1985 6. Tsujimoto Y, Cossman J, Jaffe E, Croce CM: Involvement of From www.bloodjournal.org by guest on August 3, 2017. For personal use only. SEQUENCE ANALYSIS T( 14: 18) IN FOLLICULAR LYMPHOMA the bcl-2 gene in human follicular lymphomas. Science 228: 1440, 1985 7. Bakhshi A, Wright JJ, Graninger W, Seto M, Owens J, Cossman J, Jensen JP, Goldman P, Korsmeyer SJ: Mechanism of the t( 1438) chromosomal translocation: Structural analysis of both derivative 14 and 18 reciprocal partners. Proc Natl Acad Sci USA 84:2396, 1987 8. Ngan B-Y, Nourse J, Cleary ML: Detection of chromosomal translocation t(14;18) within the minor cluster region of bcl-2 by polymerase chain reaction and direct genomic sequencing of the enzymatically amplified DNA in follicular lymphomas. Blood 73: 1759,1989 9. Tsujimoto Y, Gorham J, Cossman J, Jaffe E, Croce CM: The t( 14;18) chromosome translocations involved in B-cell neoplasms result from mistakes in VDJ joining. Science 229:1390, 1985 10. Tsujimoto Y, Louie E, Bashir MM, Croce CM: The reciprocal partners of both the t(14;18) and t(l1;14) translocations involved in B-cell neoplasms are rearranged by the same mechanism. Oncogene 2:347,1988 11. Cleary ML, Smith SD, Sklar J: Cloning and structural analysis of cDNAs for bcl-2 and a hybrid bcl-2/immunoglobulin transcript resulting from the t(l4;18)translocation. Cell 47:19, 1986 12. Ngan BY, Chen-Levy Z, Weiss LM, Warnke RA, Cleary ML: Expression in non-Hodgkin’s lymphomas of the bcl-2 protein associated with the t( 14;18) chromosomal translocation. N Engl J Med 318:1638, 1988 13. Lee M-A, Chang K-K, Cabanillas F, Freireich EJ, Trujillo 135 JM, Stass SA: Detection of minimal residual cells carrying the t(14;18) by DNA sequence amplification. Science 237:175, 1987 14. Cotter FE, Hall PA, Young BD: Extraction of DNA from small sections of frozen tissue with simultaneous histological examination. J Clin Pathol41:1125, 1988 15. Saiki RK, Gelfand DH, Stoffel S, Scharf SJ, Higuchi R, Horn GT, Mullis KB, Erlich HA: Primer-directed enzymatic amplification of DNA with a thermostable DNA polymerase. Science 239:487, 1988 16. Sanger F, Nicklen S, Coulson AR: DNA sequencing with chain-terminating inhibitors. Proc Natl Acad Sci USA 745463, 1977 17. Ward ES, Gussow D, Griffiths AD, Jones PT, Winter G: Binding activities of a repertoire of single immunoglobulin variable domains secreted from E coli. Nature 341544, 1989 18. Roth DB, Chang X-B, Wilson JH: Comparison of filler DNA at immune, nonimmune and oncogenic rearrangements suggests multiple mechanisms of formation. Mol Cell Biol9:3049, 1989 19. Haluska FG, Tsujimoto Y , Croce CM: The t(14;18) chromosome translocation of the Burkitt lymphoma cell line Daudi occurred during immunoglobulin gene rearrangement and involved the heavy chain diversity region. Proc Natl Acad Sci USA 84:6835, 1987 20. Showe LC, Moore RCA, Erikson J, Croce CM: MYC oncogene involved in a t(8;22) chromosome translocation is not altered in its putative regulatory regions. Proc Natl Acad Sci USA 84:2824, 1987 From www.bloodjournal.org by guest on August 3, 2017. For personal use only. 1990 76: 131-135 Direct sequence analysis of the 14q+ and 18q- chromosome junctions in follicular lymphoma F Cotter, C Price, E Zucca and BD Young Updated information and services can be found at: http://www.bloodjournal.org/content/76/1/131.full.html Articles on similar topics can be found in the following Blood collections Information about reproducing this article in parts or in its entirety may be found online at: http://www.bloodjournal.org/site/misc/rights.xhtml#repub_requests Information about ordering reprints may be found online at: http://www.bloodjournal.org/site/misc/rights.xhtml#reprints Information about subscriptions and ASH membership may be found online at: http://www.bloodjournal.org/site/subscriptions/index.xhtml Blood (print ISSN 0006-4971, online ISSN 1528-0020), is published weekly by the American Society of Hematology, 2021 L St, NW, Suite 900, Washington DC 20036. Copyright 2011 by The American Society of Hematology; all rights reserved.