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PubMed1993

Statistical methods in interphase cytogenetics: an experimental approach.

In situ hybridization (ISH) techniques on interphase cells, or interphase cytogenetics, have powerful potential clinical and biological applications, such as detection of minimal residual disease, early relapse, and the study of clonal evolution and expansion in neoplasia. Much attention has been paid to issues related to ISH data acquisition, i.e., the numbers, colors, intensities, and spatial relationships of hybridization signals. The methodology concerning data analysis, which is of prime importance for clinical applications, however, is less well investigated. We have studied the latter for the detection of small monosomic and trisomic cell populations using various mixtures of human female and male cells. With a chromosome X specific probe, the male cells stimulated monosomic subpopulations of 0, 1, 5, 10, 50, 90, 95, 99, and 100%. Analogously, when a (7 + Y) specific probe combination was used, containing a mixture of chromosome No. 7 and Y-specific DNA, the male cells simulated trisomic cell populations. Probes specific for chromosomes Nos. 1, 7, 8, and 9 were used for estimation of ISH artifacts. Three statistical tests, the Kolmogorov-Smirnov test, the multiple-proportion test, and the z'-max test, were applied to the empirical data using the control data as a reference for ISH artifacts. The Kolmogorov-Smirnov test was found to be inferior for discrimination of small monosomic or trisomic cell populations. The other two tests showed that when 400 cells were evaluated, and using selected control probes, monosomy X could be detected at a frequency of 5% aberrant cells, and trisomy 7 + Y at a frequency of 1%.(ABSTRACT TRUNCATED AT 250 WORDS)

Chromosome Aberrations↗
PubMed2003

B-cell monoclonal lymphocytosis and B-cell abnormalities in the setting of familial B-cell chronic lymphocytic leukemia.

BACKGROUND: Among all hematologic malignancies, B-cell chronic lymphocytic leukemia (BCLL) has the highest familial clustering (three- to sevenfold increase), strongly suggesting a genetic component to its etiology. Familial BCLL can be used as a model to study the early pathogenesis of this disease. METHODS: We examined nine kindreds from the National Cancer Institute's Familial BCLL Registry, consisting of 19 affected members with BCLL and 33 clinically unaffected first-degree relatives. Flow cytometric immunophenotyping to detect a B-cell monoclonal lymphocytosis (BCML) was performed. Monoclonality was confirmed by polymerase chain reaction analysis of whole blood DNA. Cell cycle analysis for aneuploidy was conducted. RESULTS: In all affected individuals, we observed the classic BCLL CD5/CD19/CD20/CD23 immunophenotypic patterns. Six of the 33 unaffected individuals (18%) had evidence of BCML. Additional individuals (13/33, 39%) showed some other abnormality, whereas 14 individuals (42%) were normal. Based on an estimated prevalence of 0.7% for BCML in the general population, the finding of six subjects (18%) with clonal abnormalities in this relatively modest sample was significantly greater than expected (i.e., 18% vs. 0.7%, P < 5.7 x 10(-9)). CONCLUSIONS: Individual components of BCML and other B-cell abnormalities were observed in almost half of the apparently unaffected individuals. Our findings suggested that BCML may be an early detectable abnormality in BCLL. The spectrum of some of these observed abnormalities suggested the involvement of different B-cell subpopulations or different pathways in clonal evolution. Population-based, longitudinal studies will be required to determine the incidence of BCML and other B-cell abnormalities and their relation to disease progression in BCLL and other closely related B-cell lymphoproliferative disorders.

B-Lymphocytes↗
PubMed2005

Immunophenotypic differences between diagnosis and relapse in childhood AML: Implications for MRD monitoring.

BACKGROUND: Determination of antigen expression patterns is, in addition to morphologic analysis, essential to the diagnosis of acute myeloid leukemia (AML). The present study was performed to determine (a) the degree of changes in immunophenotype and their consequences on the monitoring of minimal residual disease (MRD) in childhood AML and (b) whether certain clusters of changes in antigen expression patterns exist between diagnosis and relapse. METHODS: Bone marrow specimens of 48 children enrolled in the German AML-BFM-93/98 (Acute Myeloid Leukemia-Berlin-Frankfurt-Munster) studies were analyzed immunologically, morphologically, and genetically at diagnosis and at first relapse. RESULTS: The immunophenotypes by flow cytometry differed by at least one antigen between samples at presentation and relapse in 42 of 48 children (88%). More children displayed an immature phenotype at relapse (43 of 47, 91.5%, vs. 37 of 48, 77%; P = 0.05) with expression of CD34 and/or CD117. This was reflected by a gain of markers that are associated with lineage immaturity in 18 of 25 (72%) of cases, whereas the loss of such antigens was observed in 6 of 25 (24%) patients. We did not observe significant changes for lineage specific markers, with comparable occurrences of loss or gain of myeloid and lymphoid antigens in the sample pairs. Only minimal changes were seen for morphologic and genetic features. CONCLUSION: An antigenic shift was observed in 88% of cases in this study. The antibody panels used for MRD monitoring in childhood AML should therefore not be restricted to the immunophenotype detected at presentation but should include in particular markers of lineage immaturity. The clinical observation of a shift toward a more immature phenotype of the myeloblasts is consistent with the model of a clonal evolution of a leukemic stem cell.

Acute Disease↗
PubMed2005

Use of chromosome painting for detecting stable chromosome aberrations induced by melphalan in mice.

Chromosomal aberrations are a measure of genomic instability, which is known to play a key role in the initiation and promotion of carcinogenesis. Stable reciprocal translocations are of particular importance since they are often involved in neoplastic transformation and tumor cell clonal evolution. In this study, chromosome painting analysis was used to test for stable aberrations induced in the bone marrow of C57BL/6J and FVB mice exposed for 4 weeks to 2 or 4 mg/kg of melphalan (MLP), a chemotherapeutic agent with carcinogenic potential. To compare the chemical-induced damage in different tissues, chromosome aberrations were also analyzed by chromosome painting in the spleen of C57BL/6J mice. At the 2 mg/kg dose, MLP induced comparable levels of chromosome-type aberrations in bone marrow cells of both mouse strains and in splenocytes of C57BL/6J mice. At 4 mg/kg, no further increase in aberrations was detected in bone marrow, while a dose-effect relationship was found in spleen cells. This different response may result from a negative selection against highly damaged bone marrow cells during mitotic proliferation. The results indicate that chromosome painting is a useful tool for detecting stable chromosome aberrations in somatic cells exposed to MLP and possibly to other genotoxic chemical carcinogens.

Animals↗
PubMed2003

Cytogenetic characterization of tumors of the vulva and vagina.

Neoplasms of the vulva and vagina account for less than 5% of all female genital tract cancers. Squamous cell carcinoma (SCC) represents more than 70% of the cases in both locales, followed by melanoma, basal cell carcinoma, Paget's disease, and other carcinoma subtypes. Until recently, only few cases had been analyzed by chromosome banding techniques and karyotyped, and also the number subjected to molecular cytogenetic analysis remains low. To understand better the genetic changes harbored by the neoplastic cells in cancer of the vulva and vagina, we analyzed cytogenetically 51 such tumors, finding karyotypic abnormalities in 37. All tumors were analyzed by G-banding, sometimes supplemented by multicolor fluorescence in situ hybridization, and a subset of tumors was also analyzed by comparative genomic hybridization. The two cytogenetically abnormal cases of Paget's disease both had two clones, one with gain of chromosome 7 as the sole change, the other with loss of the X chromosome among, in one case, other aberrations. The four cytogenetically abnormal malignant melanomas (three of the vulva, one of the vagina) presented complex karyotypes with aberrations involving different chromosomes but most often chromosome 1, specifically 1p12-q41. In the 31 cytogenetically abnormal SCCs, different clonal karyotypic abnormalities were seen. Intratumor heterogeneity with multiple clones was observed in 11 cases. The clones were cytogenetically unrelated in eight tumors but related in three, indicating that in the latter clonal evolution had taken place from a single malignantly transformed cell. The main chromosomal imbalances were gains of, or from, chromosome arms 3q, 5p, 8q, 9q, and 19q, and loss from 11q. Breakpoint clusters were seen in 11q13-23, 2q22-35, and 19q13, as well as in the centromeres and pericentromeric bands of chromosomes 3, 8, 9, 13, 14, and 22.

Carcinoma in Situ↗
PubMed2001

Clinical impact of molecular and cytogenetic findings in synovial sarcoma.

Synovial sarcoma is an aggressive soft-tissue tumor that accounts for up to 10% of soft-tissue sarcomas. Cytogenetically, synovial sarcoma is characterized by the t(X;18)(p11;q11), found in more than 95% of the tumors. This translocation results in rearrangements of the SYT gene in 18q11 and one of the SSX1, SSX2, or SSX4 genes in Xp11, creating a SYT/SSX1, SYT/SSX2, or SYT/SSX4 chimeric gene. It has been shown that patients with SYT/SSX1 fusion genes have a shorter metastasis-free survival than do patients with SYT/SSX2. Previous studies have also suggested that clonal evolution may be associated with disease progression. In the present study, RT-PCR analysis showed that all 64 examined synovial sarcomas from 54 patients had SYT-SSX chimeric genes. SYT/SSX1 was found in 40 tumors from 33 patients, SYT/SSX2 in 23 tumors from 20 patients, and SYT/SSX4 in one case. Two patients had variant SYT/SSX2 transcripts, with 57 bp and 141 bp inserts, respectively, between the known SYT and SSX2 sequences. Patients with tumors with SYT/SSX1 fusions had a higher risk of developing metastases compared to those with SYT/SSX2 fusions (P = 0.01). The reciprocal transcripts SSX1/SYT and SSX2/SYT were detected using nested PCR in 11 of the 40 samples with SYT/SSX1 and 5 of the 23 samples with SYT/SSX2, respectively. Among 20 blood samples, SYT/SSX1 and SYT/SSX2 were detected in one sample each. The t(X;18), or variants thereof, was found cytogenetically in all patients but three. Among 32 primary tumors, the t(X;18) or a variant translocation was the sole anomaly in 10. In contrast, of the seven metastatic lesions that were investigated prior to radiotherapy, only one had a t(X;18) as the sole anomaly; all other tumors displayed complex karyotypes. Cytogenetic complexity in primary tumors was, however, not associated with the development of metastases. Tumors with SYT/SSX2 less often (4/12 vs. 7/15) showed complex karyotypes than did tumors with SYT/SSX1, but the difference was not significant. Combining cytogenetic complexity and transcript data, we found that the subgroup of patients with tumors showing simple karyotypes and SYT/SSX2 fusion had the best clinical outcome (2/8 patients developed metastases), and those with tumors showing complex karyotypes together with SYT/SSX1 fusion the worst (6/7 patients developed metastases). This corresponded to 5-year metastasis-free survival rates of 0.58 and 0.0, respectively (P = 0.02).

Adolescent↗
PubMed2005

Cytogenetic manifestations of multiple myeloma heterogeneity.

To investigate the genetic basis of the great heterogeneity observed in the clinical behavior of multiple myeloma (MM), a combined approach of G-banding, interphase fluorescence in situ hybridization (FISH), and multicolor FISH (M-FISH) was employed to analyze 70 samples from 53 patients with MM. G-banding revealed abnormal karyotypes in 77% of the cases. The origin of 31 chromosome markers was identified or revised by M-FISH. Combined metaphase karyotypic data and interphase FISH findings, using the immunoglobulin heavy-chain (IGH), IGH/cyclin D1 gene (CCND1), and D13S319 probes, revealed chromosome abnormalities in all evaluated patients and marked inter- and intratumor cytogenetic heterogeneity in the investigated MM samples. Cytogenetically unrelated clones were detected in 26% of the cases, mostly MM evaluated at diagnosis, whereas cytogenetic clonal evolution, manifested as related clones in 20% of the cases, was associated with disease progression. Among the 14q32 rearrangements, present in 66% of the cases, at least three cytogenetic subsets could be identified: one with t(11;14), usually without 13q14 deletion; another with other IGH changes, often 13q14 deletion, and hypodiploid modal chromosome number; and a third without changes in 14q32 but with abnormalities of chromosome 17. The correlation found between cytogenetic and clinicopathologic characteristics provided support for the concept that general genomic features in conjunction with specific chromosome rearrangements define the malignant phenotype in the various subsets of MM.

Adult↗
PubMed2005

ETV6/RUNX1 fusion at diagnosis and relapse: some prognostic indications.

This study was undertaken in order to compare the interphase and metaphase cytogenetics of 28 patients with ETV6/RUNX1 positive acute lymphoblastic leukemia, at diagnosis and relapse. The median time to relapse was 26 months. The significant fusion positive population heterogeneity revealed at interphase by a commercial probe for ETV6/RUNX1 fusion has not been described before. Six diagnostic samples had a single abnormal population; others had up to five each, which differed in the numbers of RUNX1 signals, and in the retention or loss of the second ETV6 signal. In contrast, the number of fusion signals was more constant. At relapse, there were fewer populations; the largest or unique clone was sometimes a re-emergence of a minor, diagnostic one, with a retained copy of ETV6 and the most RUNX1 signals. Abnormal, fusion negative clones were identified in bone marrow samples at extra-medullary relapse. Variant three or four-way translocations, which involved chromosomes 12 and 21, were prominent among the complex rearrangements revealed by metaphase FISH. The frequency of their occurrence at diagnosis and reappearance at relapse, sometimes accompanied by minor clonal evolution, was another new observation. Other recurrent cytogenetic features included a second copy of the fusion signal in six cases, partial duplication of the long arm of the X chromosome in two cases, and trisomy 10 in three cases. In comparing our data with previously reported cases, a picture is beginning to emerge of certain diagnostic features, which may provide circumstantial evidence of an increased risk of relapse.

Adolescent↗
PubMed1990

Uterine leiomyoma cytogenetics.

Uterine leiomyoma--a benign smooth muscle tumor--has recently been found to contain tumor-specific chromosome aberrations. Although only normal karyotypes were detected in 50 to 80% of cytogenetically investigated tumors, 104 leiomyomas with karyotypic aberrations have already been reported. At least four cytogenetically abnormal subgroups have been identified thus far, characterized by rearrangements of 6p, del(7)(q21.2q31.2), +12, and t(12;14)(q14-15;q23-24). The remaining abnormal tumors have had various nonrecurrent anomalies. Secondary karyotypic rearrangements, sometimes including ring chromosomes, have been found in one-third and reflect clonal evolution. Occasional leiomyomas have contained multiple numerical and structural rearrangements. Though benign, these cytogenetically grossly aberrant tumors often displayed more atypical histological features than are usually seen in leiomyoma. Multiple leiomyomas have been investigated from 69 patients, with detection of chromosome anomalies in at least two separate tumors from the same uterus in ten cases. In half of these patients unrelated aberrations were found in different leiomyomas from the same uterus. On other occasions the aberrations were identical, indicating that although some uterine leiomyomas originate independently, others may develop by intra-myometrial spreading from a common neoplastic clone. Some common features are discernible between the karyotypic pictures of uterine leiomyoma and angioleiomyoma; rearrangements of 6p, 13q, and 21q have been described in both tumor types. The cytogenetic similarities so far detected between leiomyoma and the malignant muscle tumors--leiomyosarcoma and rhabdomyosarcoma--are few and may be fortuitous. The cytogenetic profiles of leiomyoma and lipoma are strikingly similar; both tumor types have nonrandom rearrangements of 12q13-15, t(12;14) in leiomyoma and t(3;12) in lipoma, as well as variant rearrangements of the same 12q segment. Both also have cytogenetic subgroups characterized by changes in 6p and ring chromosomes. Finally, karyotypic similarities exists also between leiomyoma and pleomorphic adenoma of the salivary gland, which includes a subset of tumors with anomalies of 12q13-15, and with myxoid liposarcoma, which has t(12;16)(q13;p11) as a tumor-specific rearrangement.

Chromosome Aberrations↗
PubMed1990

Leukemia characterized by multiple sub-clones with unbalanced translocations involving different telomeric segments: case report and review of the literature.

A 68-year-old man presented with t(4;11)(q21;q23), B-lineage acute lymphoblastic leukemia (ALL) which was negative for C-ALL antigen and TdT. Clonal evolution to five different, but related karyotypes, in which chromosomal material distal either to 1q11 or 1q21 was translocated to the terminal regions of 4q-, 11q, 16q, and 19p resulted in partial or total trisomy of 1q. The patient, having achieved a short remission, died 14 weeks after diagnosis. Five reports of jumping translocations in hematological malignancies, four with B-lineage malignancy, are reviewed. One (four cases) or both (one case) of the same 1q breakpoints were consistently found and 11q and 16q were repeatedly involved. Such cases, having multiple subclones with trisomy 1q, may form a distinct subgroup of ALL.

Aged↗
PubMed1991

t(18;22)(q21;q11) with rearrangement of BCL2 as a possible secondary change in a lymphocytic lymphoma.

We report a lymphocytic lymphoma showing a combination of two characteristic neoplasia-associated chromosomal changes: trisomy 12, commonly observed in chronic lymphocytic leukemia and lymphocytic lymphoma, and t(18;22)(q21;q11), a variant form of the t(14;18)(q32;q21) found in most follicular lymphomas. Southern blot analysis was performed using probes for the 5' end of the BCL2 gene (18q21) and for the J lambda as well as C lambda immunoglobulin genes (22q11). With these two probes, a unique rearranged fragment was detected. Thus the t(18;22)(q21;q11) can be considered as a variant translocation of t(14;18)(q32;q21). The karyotypic analysis supports the assumption that in our case trisomy 12 occurred first, and t(18;22) appeared during tumor progression as part of the clonal evolution. This is at variance with the typical t(14;18), which has never been found to occur as a secondary change.

Blotting, Southern↗
PubMed1991

Cytogenetics of synovial sarcoma: presentation of ten new cases and review of the literature.

Cytogenetic study of five biphasic and five monophasic synovial sarcomas revealed the specific abnormality t(X;18) (p11;q11) in eight cases and t(X;15;18) (p11;q15;q11) and t(X;7) (q11-12;q32) in one case each. Additional, secondary aberrations were present in eight of these tumors. By combining our data with information on previously published cytogenetically abnormal synovial sarcomas, we were able to evaluate 32 tumor samples from 29 patients. The modal chromosome number was pseudodiploid or near diploid in 26 of the 32 tumors. A t(X;18) was present in 21 of 29 cases (72%). Complex translocations involving chromosomes X and 18 and another autosome were present in five cases, and one displayed a t(5;18). There was no visible rearrangement of chromosome bands Xp11 or 18q11 in only 2 of the 32 synovial sarcomas. Half of the primary tumors (6 of 12) had the X;18-translocation as the sole abnormality. Of the remaining 20 specimens from recurrent or metastatic tumors (in three cases two tumors could be analyzed), only one had t(X;18) as the sole change. The secondary aberrations in cases exhibiting clonal evolution were also generally more extensive in the metastatic and recurrent than in the primary sarcomas (five additional aberrations per case, compared with two). Chromosomes 1 and 12 were the chromosomes most frequently (one fourth of the cases) involved in additional structural changes, but with several different breakpoints. No differences were identified between the karyotypic profiles of monophasic and biphasic synovial sarcomas.

Adolescent↗
PubMed1991

Multiple DNA rearrangements in the BCL2 region in a patient with follicular lymphoma.

A 39-year-old male with follicular non-Hodgkin's lymphoma was repeatedly studied with respect to DNA rearrangements with the two probes pFL-1 and pFL-2, representing two segments of chromosome 18. The oncogene BCL2, detected by pFL-1, was as expected translocated to the J region of the immunoglobulin locus. The standard BCL2 translocation was found in three samples, one obtained at diagnosis, one ten months later, and one after 5 years. Another translocation was found with the probe pFL-2 hybridizing with a region located about 20 kb 3' from BCL2. This latter rearrangement was found only in the first biopsy, which was obtained at the time of diagnosis, but not in the two later samples, when the morphology of the lymphoma was unchanged. No cytotoxic therapy had been given in the interval from diagnosis to disappearance of the latter rearrangement. Thus, one of the observed translocations (pFL-2) was detected only in the first biopsy, while the other (pFL-1) was a clonal marker in all three biopsies. The finding suggests that clonal evolution does not necessarily mean clinical progression.

Adult↗
PubMed1992

Rearrangements of chromosome arm 3q in poorly differentiated nasopharyngeal carcinoma.

Cell lines were established from fresh tumor biopsies from two Saudi patients with poorly differentiated nasopharyngeal carcinoma (NPC). Cytogenetic analysis on Giemsa-banded metaphase cells revealed complex, abnormal karyotypes in both patients with modal chromosome numbers of 77 and 52. A der(3)dup(3)(q25-q2?7) or t(3;?)(q27;?) was observed in both cell lines. The rearrangements involving chromosomes X, 1, 4, 6, 7, 8, 12, 13, 15, 17, and 22 in the first patient and 1, 6, and 22 in the second patient could represent clonal evolution.

Adult↗
PubMed1992

Is cancer cytogenetics reducible to the molecular genetics of cancer cells?

Whether cancer cytogenetics can be reduced to the molecular genetics of cancer cells is a question that must be addressed in three domains, focusing on its ontological, methodological, and epistemological dimensions. The possibility of ontological reduction hinges on whether chromosomes have other important constituents than molecules. Although this must obviously be answered in the negative, it should be emphasized that both cytogenetic and recombinant DNA investigations provide us with very selective pictures of genomic organization. This is of concern because the higher order packing of DNA and its joining with other molecules to form chromosomal structures give rise to emergent properties, functional features that become manifest only at higher levels of complexity and that may not be deducible from the base pair composition of the DNA. A position of extreme methodological reductionism would in our context be that the best research strategy is always to investigate the genetic changes of tumor cells at the highest possible resolution level, as alterations of genes and, ultimately, as changes in DNA primary structure. There are two fundamental differences between cytogenetic and molecular genetic techniques that make this stance untenable. First, whereas cytogenetic investigations are open-framed (all chromosome aberrations are revealed), molecular genetic analyses are highly specific (only those aberrations are revealed that one tests for). Second, whereas the molecular approach determines the genotypic constitution of an idealized, average tumor cell, cytogenetic analysis is of real, individual cells. These may not necessarily be representative of the main population of the tumor, but at least whatever karyotypic differences exist between them are detected. Heterogeneity and clonal evolution within the tumor can thereby be assessed.(ABSTRACT TRUNCATED AT 250 WORDS)

Chromosome Aberrations↗
PubMed1993

Oligoclonal B-cell leukemia characterized by spontaneous cell division and telomere association.

Cytogenetic analysis of unstimulated cultures from a female patient with chronic B-cell leukemia (CLL) revealed three cytogenetically distinct clones, suggesting that the patient's leukemia was oligoclonal. Immunoglobulin heavy chain gene rearrangement studies revealed 1 germline and 4 rearranged bands, indicative of an oligoclonal leukemic population. Further evidence of oligoclonality was provided by X-linked RFLP studies. This is the first report of oligoclonality in CLL demonstrated by cytogenetic, immunoglobulin gene rearrangement, and X-chromosome inactivation studies. In addition to oligoclonality, the patient's leukemic cells exhibited telomere association, a Robertsonian translocation, and clonal evolution, suggesting an underlying genomic instability.

Cell Division↗
PubMed1994

Consistent chromosomal losses in head and neck squamous cell carcinoma cell lines.

Clonal chromosomal abnormalities were characterized in nine cell lines established from squamous cell carcinomas of the head and neck. Aneuploidy was a common feature; one cell line was near-diploid, three were near-triploid, four were near-tetraploid, and one cell line showed extensive variation in chromosome numbers. Consistent numerical abnormalities included loss of the sex chromosomes in six cell lines, losses of chromosomes 2 and 21 in six and five cell lines, respectively, and gain of chromosome 20 in five cell lines. Recurrent structural rearrangements included del(10)(q22-q26) (seven cell lines), i(5)(p10) (six cell lines), i(8)(q10) (six cell lines), add(19)(q13) (six cell lines), del(4)(q21-q31.3) (five cell lines), i(3)(q10) (four cell lines), del(12)(p11.1-p12) (four cell lines), and add (18)(q21-q23) (four cell lines). Other changes were noted in lower frequencies. Loss of specific regions on chromosomes 2, 3p, 4q, 5q, 8p, 10q, 12p, 18q, 19q, and 21 suggests that they may represent sites of putative tumor suppressor genes, loss of which may play a role in the pathogenesis of squamous cell carcinomas of the head and neck. Alternatively, gain of chromosomal region 3q, 5p, and 8q due to isochromosome formation suggests that more than one mechanism is involved in malignant transformation. Cytogenetic evidence of gene amplification was found in two cell lines; as an hsr(11)(q13) in one and as dmins in the other. The clonal karyotypes of four cell lines were compared with those of their respective primary tumors. In all cell lines, clonal evolution had occurred, with loss of some rearrangements present in the primary tumors or the gain of additional abnormalities.

Aged↗
PubMed1995

Atypical cytogenic aberrations in two childhood peripheral primitive neuroectodermal tumors.

Atypical cytogenetic abnormalities were detected in peripheral primitive neuroectodermal tumors (PPNET) of the extremity in two children. One had an osseous tumor with a balanced reciprocal translocation, t(5;9)(q22;q32), and had a complete response to therapy. The other had a non-osseous tumor with an interstitial deletion, del(18)(q12.2q21.2), was resistant to combination therapy, and at autopsy had evidence of possible clonal evolution with the karyotype 46,XX der(8)t(8;8)(p11.2;q13), inv(16)(p13.2q12),del(18)(q12.2q21.2). Neither tumor demonstrated the t(11;22)(q24;q12) typically found in Ewing's sarcoma and PPNET, suggesting heterogeneity of the cytogenetic aberrations seen in this rare childhood malignancy.

Bone Neoplasms↗