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Objectives: Cytogenetic studies on cutaneous lymphomas are rare, and very little is known about their prognostic value. We present a rare case of primary cutaneous follicle center lymphoma (PCFCL) with a complex translocation presenting with cutaneous and extracutaneous dissemination in the lymph node., Methods: Morphologic, immunohistochemical, conventional cytogenetic, and fluorescence in situ hybridization (FISH) studies were performed on this patient., Results: A combination of cytogenetic and FISH analysis identified a complex novel four-way t(2;14;9;3) (p11.2;q32;p13;q27) translocation involving rearrangements of BCL6, immunoglobulin light and heavy chain genes, and an unknown gene on 9p., Conclusions: Our report elaborates the morphologic and immunohistochemical features in combination with cytogenetic and molecular cytogenetic analysis of PCFCL, which provide additional insight into the clinical and biologic behavior of this lesion., (Copyright© by the American Society for Clinical Pathology.)

The chromosome 22q11.2 region is susceptible to rearrangements, mediated by low copy repeats (LCR22s). Deletions and duplications are mediated by homologous recombination events between LCR22s. The recurrent balanced constitutional translocation t(11;22)(q23;q11) breakpoint occurs in an LCR22 and is mediated by double strand breaks in AT-rich palindromes on both chromosomes 11 and 22. Recently, two cases of a t(17;22)(q11;q11) were reported, mediated by a similar mechanism (21). Except for these constitutional translocations, the molecular basis for non-recurrent, reciprocal 22q11.2 translocations is not known. To determine whether there are specific mechanisms that could mediate translocations, we analyzed cell lines derived from 14 different individuals by genotyping and FISH mapping. Somatic cell hybrid analysis was carried out for four cell lines. In five cell lines, the translocation breakpoints occurred in the same LCR22 as for the t(11;22) translocation, suggesting that similar molecular mechanisms are responsible. An additional three occurred in other LCR22s, and six were in non-LCR22 regions, mostly in the proximal half of the 22q11.2 region. The translocation breakpoints on the partner chromosomes were all located in the telomeric bands, proximal to the most telomeric unique sequence probe, in eight cell lines and distal to those loci in six. Therefore, several of the breakpoints were found to occur in the vicinity of highly dynamic regions of the genome, 22q11.2 and telomeric bands. We hypothesize that these regions are more susceptible to breakage and repair, resulting in translocations.

Objectives/hypothesis: The genetic content of head and neck squamous cell carcinomas is ill defined. Spectral karyotyping (SKY) is a new technique that allows the simultaneous detection of all chromosomal translocations by labeling each individual chromosome with different fluorescent agents. In the current study we used SKY to analyze cell lines and a primary tumor derived from head and neck squamous cell carcinomas (HNSCC) to delineate recurrent translocations and breakpoints., Study Design: Spectral karyotyping analysis of head and neck cancer., Methods: Two cell lines (MDA886 and MSK922) and one primary tumor in short-term culture were subjected to metaphase growth arrest with colcemide in their exponential growth phase and fixed onto glass slides. Painting probes for each of the autosomes and the sex chromosomes were generated from flow-sorted human chromosomes using sequence-independent DNA amplification. The probes were labeled using a polymerase chain reaction-based reaction and hybridized to metaphase preparations for 2 days at 37 degrees C. Biotinylated probes were detected using avidin Cy5 and digoxigenin-labeled probes with an anti-mouse digoxigenin antibody followed by goat anti-mouse antibody conjugated to Cy5.5. Chromosomes were counterstained with 4,6-diamino-2-phenyliodole (DAPI), and a minimum of five metaphases were captured and analyzed for each case. Breakpoints on the SKY-painted chromosomes were determined by comparison of corresponding DAPI banding., Results: Spectral karyotyping analysis revealed a complex pattern of chromosomal abnormalities. A total of 66 translocations were identified in the three cases, with one new recurrent translocation at (der(4)t(4;20)(q35;?)). Nine complex translocations, involving three or more chromosomes, were identified in these cases. Overall, 96 breakpoints were assigned to metaphase chromosomes and another 74 breakpoints could not be assigned. Breakpoints most commonly involved chromosomes in genetic rearrangements were 1, 3, 5, 8, 13, 16, and 17., Conclusions: Spectral karyotyping analysis reveals the true complexity of chromosomal aberrations in cell lines derived from head and neck squamous cell carcinomas. The use of SKY, in combination with other techniques, may allow for a more complete assessment of the genetic abnormalities of head and neck cancers and serve as a starting point for gene identification.

Acute promyelocytic leukemia (APL;M3) is specifically characterized by a predominance of malignant promyelocytes having atypical reciprocal translocation involving chromosome 15 and 17 [t(15;17)(q22;q11)] resulting in the fusion of retinoic acid receptor alpha (RAR alpha) on chromosome 17 and the putative transcription factor gene PML, ie the translocation generates two fusion transcripts, PML/RAR alpha and RAR alpha/PML. We describe a patient with clinical and morphologic characteristics of atypical APL but with a previously undescribed variant translocation. A 35-year-old Hispanic having atypical APL was referred for cytogenetic evaluation. The cytogenetic findings with GTG-banding coupled with FISH analysis revealed the following karyotype: 46,XX,der(9)t(1;9)(q25;q34)der(9)t(9;?)(q34;?), t(15;17)(q22;q11)ish. der(9)t(1;9)(q25;q34)(WCP1+,WCP9+),t(9;17;15)(q34;q11;q22) (WCP9+,WCP15+,PML+;WCP17+,RAR alpha +;WCP15+,WCP17+,PML-)[20]/46,XX[5]. The chromosome 17q was translocated to the chromosome 15q. However, chromosome 15q including the PML gene normally translocating to 17q and creating the RAR alpha/PML fusion gene, translocated to chromosome 9q. Does this patient have another subset of APL? Or is the genetics of APL different in cases with variant translocations as opposed to those with atypical t(15;17) translocation, though in the majority of the cases their clinical presentation remains the same.

A patient was referred with a high leukocyte count and diagnosed with chronic myelogenous leukemia (CML). Although practically asymptomatic since the time of diagnosis, he had a variable and inconsistent response to treatment. All of his bone marrow cells had a complex, three-way translocation, involving chromosomes 4, 9 and 22. Translocation of chromosome 4 to chromosome 9 was undetectable by routine cytogenetic techniques; however, by the fluorescence in situ hybridization technique, a three-way translocation was identified, 46,XY,t(4;9;22)(p16;q34;q11). Although, other chromosomes are frequently involved in complex or variant translocations with chromosome 9 and 22, participation of chromosome 4 is a very rare event. So far, two previous cases have been described in the literature with translocations involving chromosome 4p16. We present a third case of CML having similar break points whose clinical presentation is unusual.

We report a case of acute myelogenous leukemia with a variant translocation involving chromosomes 5 and 21 with breakpoints on 5q13 and 21q22 as revealed by various techniques including fluorescence in situ hybridization. The unusual presentation of t(5;21)(q13;q22), as the sole abnormality in acute myelogenous leukemia, is atypical.

Human T-lymphotropic virus type I (HTLV-1) integration has been associated with the development of adult T-cell leukemia/lymphoma (ATL). Recently, a correlation between T-cell receptor (TCR) gene rearrangements and chromosomal aberrations has been implicated in this leukemia. We present a case of HTLV-1 infected adult T-cell lymphoma that initially presented with a normal karyotype and germline J beta I/J beta II loci. As the disease evolved to the aggressive stage, a complex chromosomal rearrangement with a duplication of chromosome 6p23-->pter translocated to a derivative chromosome 16, was identified by molecular cytogenetic techniques. The nature of this complex abnormality would have been difficult to determine if only conventional banding techniques were performed. Rearrangement involving one J beta allele was also detected at that time. After initiation of chemotherapy, no germline J beta loci were detected, suggesting a possible second rearrangement involving this locus that was homologous. Although no known immune response genes are located at the breakpoints involved in this abnormality, the chromosomal aberration concurred with the initial J beta rearrangement.

A case with typical features of chronic myelogenous leukemia (CML) with two complex aberrations in addition to the standard t(9;22) is reported. Cytogenetic evaluation of the patient's bone marrow cells (BMC) showed 46,XX,t(6;19)(q16;p13.3),t(9;22)(q34;q11) in 60% of the mitotic cells and 46,XX,idem, t(6;15)(p25;q22) in the remaining 40% dividing cells. The patient's peripheral blood smear exhibited the usual differential observed in chronic-phase CML and was clinically indistinguishable from patients with the t(9;22) as the only translocation. We performed Southern blotting on BglII-digested DNA with the Trans-Probe (OSI) and in addition to the 4.8-, 2.3-, and 1.1-kilobase (kb) germline fragments, we detected an additional fragment at 7 kb. This probe spans the entire 5.8-kb M-breakpoint cluster region (BCR), and a single breakpoint in this region will appear as either one or two additional fragments. Because only one additional fragment was observed, both cell lines apparently share the same breakpoint in the ABL/BCR gene. Apparently the second aberrant cell line with the additional t(6;15) represents clonal evolution of the original abnormal clone.

An apparent balanced translocation involving the long arms of homologous chromosomes is described for the first time in a patient with acute myelogenous leukemia (AML) (M2), i.e., 46,XY,t(3;3) (q21;q26). After reviewing the literature, it was noted that a breakpoint involving band 3q26 is a frequent anomaly in other translocations. Thus, we are tempted to hypothesize that 3q26 band may also play an important role in the pathogenesis of AML (M2).