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The t(9;22)(q11.2;q34) translocation is found in a subset of acute lymphoblastic leukemia (ALL). The presence of this translocation involving the fusion of BCR/ABL genes represents a poor prognostic group. Because of the importance in detecting t(9;22) in ALL patients and because occasionally a cytogenetically cryptic BCR/ABL fusion is detected with fluorescence in situ hybridization (FISH), our laboratory routinely performs BCR/ABL FISH tests on all newly diagnosed ALL patients. In the past year, 25 consecutive, newly diagnosed, untreated ALL cases were analyzed. We report the cytogenetics and FISH findings of three cases containing a rearranged 9q34 region with an intact BCR (22q11.2) region and an absence of the BCR/ABL fusion. A split ABL signal representing a translocation of the 9q34 region with chromosome segments other than 22q11.2 (BCR) was observed in 3 cases. Two of these patients were 3 years old; one was 21 at the time of diagnosis. A split ABL FISH signal without the involvement of BCR does not represent a t(9;22) translocation, and prognostic implications of this apparent subgroup of ALL cases have not been determined. Cytogenetic, pathologic, and clinical aspects of these three cases are presented.

Diffuse large B-cell lymphoma (DLBCL), the most common subtype of adult non-Hodgkin lymphoma (NHL), is infrequently seen in adolescents and is rare in children. Due to the infrequency of the disease, single institution-based cytogenetic and fluorescence in situ hybridization (FISH) studies of pediatric DLBCL have not been reported so far and, hence, the possible differences in pediatric and adult DLBCL have not been evaluated. We performed cytogenetic and FISH analyses of 7 pediatric and 5 young adult DLBCL cases referred to the University of Nebraska Medical Center. Karyotypic studies revealed numeric and structural chromosome abnormalities in all cases. Loss of chromosomes 2, 3, 4, 6, 12, 15, 16, and 17, and gain of 12, 18, and X were observed in more than 20% of the cases (#10878;3 cases). Sex chromosome abnormalities and cytogenetically unidentifiable chromosomes and/or segments were observed in 80% (10/12) of the cases. Recurrent breakpoints (observed in 3 or more cases) included 14q32 (IGH) and 17p13 (TP53), which clustered in the young adult group. The breakpoints 7q36, 9p24, 13q34, and 16q24 were noted in two cases each. We performed interphase FISH studies to verify the possible rearrangements of the breakpoints that are frequently implicated in adult DLBCL. Our results confirmed that the pediatric cases did not show rearrangements of 3q27 (BCL6), 14q32 (IGH), 18q21 (BCL2), 8q24 (CMYC), and 17p13 (TP53), except for one case with IGH;BCL2 dual fusion [t(14;18)(q32;q21)] and one with a 17p13 (TP53) deletion. Although 3q27 was noted to be rearranged by conventional cytogenetics in two young adult DLBCL cases, FISH investigations verified that BCL6 was not disrupted. The t(8;14)(q24;q32) with rearranged CMYC ascertained by FISH, was observed in a single young adult DLBCL case. These results highlight a distinctly different representation of cytogenetic abnormalities in pediatric versus adult DLBCL.

We have employed multi-color fluorescence in situ hybridization (M-FISH) to characterize the cytogenetic changes in 20 diffuse large B-cell lymphomas (DLBCL), that contained complex and partially characterized karyotypes. The M-FISH analysis helped to delineate 94% of the unidentified abnormalities and assisted in redefining some unidentified/misidentified karyotypic changes. Recurrent breakpoints observed in approximately 20% cases included 14q32, 3p21, 3q27, 22q12, 1q25, and 18q21 (in decreasing order), and 1p22, 1q21, 4q31, 6q21, and 8q24 (in four cases each). Numerical gain of chromosomes 7, 9, 12, and X and loss of chromosomes 1, 4, 6, 17, and Y, were noted in approximately 20% of cases. The minimum deleted regions encompassed 6q21-q25, 1p22-p36, 1q32-q44, 2p23-p25, 4q31-q35, 13p13-q14, and 17p11-p13. Two cases presented with a sole structural abnormality, and one contained a der(17)t(9;17)(p21;p13), which has not been reported earlier as a sole abnormality in DLBCL. Upon completely characterizing the karyotypes, we observed with interesting that in 55% of the cases, more than one BCL gene bearing regions was involved in translocations. In the remaining 45%, where only one or none of the BCL gene regions was involved in a rearrangement, we observed the loss of chromosomes 6 and/or 17 or partial deletions of 6q and/or 17p or gain of 7 and/or 12. Our findings suggest that, although BCL2 and BCL6 are most often implicated in DLBCL, the possibility of the disruptions of BCL3, BCL8, BCL9, and BCL10 as a "primary event" in DLBCL cannot be ruled out. Most often, a combination of events may be necessary for the genesis of DLBCL or progression of follicular lymphoma to DLBCL. Overall, M-FISH has enhanced our ability to provide a comprehensive karyotypic analysis, and has helped in defining the importance of BCL3, BCL8, BCL9, and BCL10 carrying breakpoints in DLBCL.

Identification of clonal chromosomal abnormalities involving 14q32 and its association with specific histological subtypes of non-Hodgkin lymphoma (NHL) has provided substantial insight to the genetic events leading to the disease. However, in some cases with inferior morphology of tumor cell chromosomes, the additional segment on chromosome 14 remains unidentified by cytogenetic banding techniques alone. To elucidate the origin of the additional chromosomal segment and to correlate the newly determined alterations with histology, metaphases from 15 NHL patients with add(14)(q32) were examined using fluorescence in situ hybridization (FISH) techniques after cytogenetic analysis had been performed. We found the duplication of 14q involving the q32 region in 6 cases with a dup(14) (q32) in 4 cases and a dup(14)(q24q32) in 2 cases. In 8 cases, FISH unveiled known NHL associated translocations; a t(14;18)(q32;q21) in 4 cases, a t(11;14)(q13;q32) in 2 cases, a t(8;14)(q24;q32) and a t(9;14)(p13;q32) in 1 case each. We also noted a t(14;17)(q32;q21) in 1 case. The use of FISH was a valuable asset in determining the origin of the additional material on chromosome 14q32, and helped resolve a group of B-cell NHLs with involvement of a duplicated 14q32 region.

Our laboratories have documented a significantly high occurrence of chromosome 1p36 rearrangements in non-Hodgkin lymphoma (NHL). The cell division cycle 2-like 1(CDC2L1) (also known as TP58 or PITSLRE) gene, a protein kinase implicated in apoptotic signaling, is located at the very distal region of chromosome 1p36 and is likely to be disrupted by structural rearrangements involving 1p36. To determine the molecular consequences of the recurrent involvement of the 1p36 region, we examined metaphases containing 1p36 abnormalities from 31 specimens derived from 26 patients for the possible deletion of CDC2L1 by fluorescence in situ hybridization (FISH) using the TP58clk-1 DNA probe. Twenty-three cases exhibited the loss of CDC2L1 from the abnormal chromosome 1. In 2 of 26 cases, the gene locus was translocated to the partner chromosome, and in four specimens, all derived from one case, CDC2L1 was not deleted. This pilot investigation suggests that 1p36 rearrangements, and consequently the loss of the CDC2L1 gene locus, is important in NHL. This work also opens avenues for further molecular studies and prognostic correlations.

The purpose of this study was to correlate abnormalities in chromosome 14 with the invasive metastatic phenotype of K-1735 murine melanoma cells. Low metastatic K-1735 clone 10 and clone 23 cells were transfected with either basic fibroblast growth factor (bFGF), Kaposi's fibroblast growth factor (kFGF), or c-H-ras gene. A high number of bFGF- and H-ras-transfected cells exhibited chromosome 14 rearrangements. These cells also had increased expression of collagenase IV. The kFGF-transfected cells were highly metastatic but did not have increased expression of collagenase type IV. The kFGF-transfected cells were highly metastatic but did not have increased expression of collagenase type IV, nor abnormalities in chromosome 14. The data imply that karyotypic changes in chromosome 14 are associated with increase expression of collagenase type IV.

Chromosomal analyses of lymphocytes from lung cancer patients and normal subjects revealed that the X and the Y chromosomes have both structural and numerical abnormalities in higher frequency in patients compared to the controls. These abnormalities included chromatid/isochromatid breaks, translocations, ring formation, and selective nondisjunctions, resulting in multisomies of either the X or Y chromosomes. Possible significance of these genetic abnormalities are discussed in relation to lung cancer patients.

The heteromorphism of constitutive heterochromatin in chromosomes #1, #9, and #16 was investigated in 44 chronic myelocytic leukemia patients and 44 controls using bone marrow and peripheral blood lymphocyte cultures. A significant increase in the length of C-band region in all the three chromosome pairs as well as a statistically significant difference in the homologs of chromosome #1 was observed in chronic myelocytic leukemia patients when compared with the controls. The frequency of inversions was also greater in the patients than in the controls. A random translocation of 22q was found on either homolog of chromosome #9.

Thirteen healthy females and thirteen untreated patients with carcinoma of the uterine cervix were studied for spontaneous and mitomycin C (MMC)-induced rates of sister chromatid exchange (SCE) and cell cycle progression. The mean values of spontaneous as well as MMC-induced SCE rates showed no statistically significant difference between groups. For studying cell cycle progression, cells in the M1, M2, and M3 stages were scored from the same samples. The percent values of cells in these stages, identified by the nature of differential sister chromatid staining, were found to be almost identical in normal as well as MMC-treated cultures in controls and patients. It was concluded that the presence of carcinoma of the uterine cervix in human females has no bearing either on spontaneous and MMC-induced SCE rates or on cell cycle progression in PHA-stimulated cultures of peripheral blood lymphocytes.