Gliosis specimens contain clonal cytogenetic abnormalities

Gain of chromosome 7, as detected by in situ hybridization, strongly correlates with shorter survival in astrocytoma grade 2

The clinical course of astrocytoma grade 2 (A2) is highly variable and is not reflected by morphological characteristics. Earlier studies using small series of A2 cases suggest that in situ hybridization (ISH) with chromosome-specific DNA probes allows for frequent detection of aneusomy 1, trisomy 7, and monosomy 10. The role of trisomy 7 in astrocytoma carcinogenesis is disputed, however, because of its presence in non-neoplastic brain tissue, as detected by karyotyping. Our objective was to investigate whether there was a correlation between chromosomal aberrations and survival in a series of 47 cases of A2. All cases were evaluated for numerical aberrations of chromosomes 1, 7, and 10 by ISH. Chromosomal aberrations were detected in 68% of cases of A2. Trisomy/polysomy 7 was seen in 31 cases (66%), 22 of which (47%) had a high percentage of this numerical aberration. Only 11 of these 22 cases also showed aneusomy for 1 or 10. No cells or only a few cells with aberrations were detected in non-neoplastic control samples. Using Kaplan-Meier analysis, trisomy/polysomy 7 correlated significantly with shorter survival. Hence, as determined by ISH, trisomy/polysomy 7 is absent in non-neoplastic brain tissue and is frequently detected in A2, correlating with the malignant progression of the disease.

Clonal chromosome abnormalites found in three non-neoplastic proliferative brain lesions

Chromosome analysis was made of brain lesions from three patients which, according to classical histopathological criteria, did not contain tumor cells. In addition to normal cells, we identified abnormal karyotypes with clonal numerical and structural chromosome alterations in at least two independently originated primary cultures from each lesion. Our data suggest that chromosomal aberrations can exist in vivo in non-neoplastic lesions. Other abnormalities may be due to genetic instability manifested only in vitro (culture artifacts) or may already have been present in brain tissue, reflecting previous chromosome damage (as a result of exposure to chemical treatment or enviromental clastogens).

Are juvenile pilocytic astrocytomas benign tumors? A cytogenetic study in 24 cases

We performed a cytogenetic study on 24 pilocytic astrocytomas: 23 in children and 1 in a young adult. We observed 12 normal karyotypes. In 12 karyotypes with structural and/or numerical abnormalities, chromosomes 7, 8, and 11 were most frequently involved. One case recurred and presented chromosomal abnormalities (hyperdiploidy) in the first tumor and additional structural abnormalities in the second tumor. We believe that chromosomal abnormalities in pilocytic astrocytomas are frequent and indicate tumoral progression.

Chromosomal characteristics of childhood brain tumors

In the present cytogenetic analysis of 116 pediatric brain tumors, chromosomal abnormalities were demonstrated in 44 cases, 48 cases revealed only 46,XX or 46,XY cells, and 24 cases were nonproductive. In contrast to studies of adult brain tumors in which isolated loss of one X or the Y chromosome is often encountered, 45,X,-X and 45,X-Y stemlines or sidelines were not observed in this series of childhood tumors. Among the 17 medulloblastomas with cytogenetic abnormalities, chromosome 1 was most frequently affected by structural deviations; the most prevalent specific alteration (7 of 17 tumors) was loss of 17p, through i(17)(q10) or unbalanced translocation. The majority of low grade astrocytomas had normal stemlines, although one pilocytic astrocytoma and one cerebellar astrocytoma had frequent telomeric associations and a second pilocytic astrocytoma had a clone with trisomy 11. Thirteen of 19 high-grade and recurrent astrocytic tumors had abnormal stemlines that were approximately equally divided among cases with chromosomal counts in the near-diploid, hyperdiploid, and near-triploid-tetraploid ranges. Although no consistent abnormalities were observed, subsets of cases had structural abnormalities of chromosome 3, 7q, 9q, or 17p. The cases of childhood brain tumors described here demonstrate that 45,X,-X, and 45,X,-Y stemlines or sidelines are rare in these tumors and confirm frequent loss of 17p in medulloblastomas. High-grade astrocytic tumors in children frequently have abnormal stemlines, often in the hyperdiploid and polyploid ranges, and they differ from high-grade gliomas in the adult by lacking consistent numerical and structural deviations.

Giant cell tumor of tendon sheath is a polyclonal cellular proliferation

Giant cell tumor of tendon sheath (GCTTS) is a common soft tissue tumor. Immunophenotypical evidence suggests it is of synovial cell origin. There is controversy regarding the underlying nature of this lesion, specifically whether it is a neoplastic or nonneoplastic (ie, reactive or hyperplastic) process. Karyotypic abnormalities have been identified in GCTTS and interpreted as evidence of neoplasia, although the finding of similar karyotypic abnormalities in unequivocally nonneoplastic proliferations raises questions about using such findings to define a neoplasm. In an attempt to resolve this uncertainty, a polymerase chain reaction (PCR)-based assay for methylation of the X-linked human androgen receptor gene (HUMARA) was used to assess whether GCTTS is a clonal or polyclonal proliferation. DNA was isolated from formalin-fixed, paraffin-embedded tissue blocks from eight cases of digital GCTTS in female subjects; two cases of hepatocellular carcinoma (HCC) were used as clonal controls. Seven of eight cases of GCTTS were informative, and each showed a polyclonal proliferation, whereas both cases of HCC were clonal. Our results indicate that GCTTS is a nonneoplastic proliferation, if one accepts that a population of cells forming a tumorous mass must show clonality to be classified as a neoplasm. Our results emphasize that simple karyotypic abnormalities do not define a neoplasm. It remains to be determined whether GCTTS is a reactive or hyperplastic process.

Clinical significance of cytogenetic findings in solid tumors

Chromosome analysis of solid tumors is becoming an increasingly useful tool to help establish a correct diagnosis and to provide prognostically important information. Characteristic karyotypic patterns in terms of degree of cytogenetic complexity and type of nonrandom abnormalities may help to distinguish neoplasia from a nonneoplastic lesion and to differentiate between a benign and a malignant tumor. More importantly, the presence of a specific or pathognomonic change may confirm or refute a suspected diagnosis, provide an alternative, unsuspected diagnosis, and trace the origin of a metastasis. Presently, specific cytogenetic abnormalities may be of substantial, and sometimes decisive, help in four groups of differential diagnostic dilemmas: (1) Benign vs. malignant epithelial tumors of the kidney, thyroid gland, salivary glands, and ovary; (2) Benign vs. malignant mesenchymal tumors of adipose and muscle tissue; (3) Differentiation between various malignant bone and soft tissue tumors: and (4) Diagnosis of undifferentiated small-cell round-cell tumors. In addition to the diagnostic value, karyotypic findings may provide prognostic information. Thus, the presence of an abnormal clone and/or complex rearrangements is a poor prognostic sign in, e.g., carcinomas of the ovary, prostate, bladder, colon, and pancreas. Furthermore, characteristic cytogenetic aberrations are now known to be valuable prognostic parameters in malignant melanoma, malignant fibrous histiocytoma, germ cell tumors, neuroblastoma, and squamous cell carcinoma of the head and neck region. Many of the correlation analyses are preliminary, but they all point in the same direction, namely that cytogenetic studies will soon play the same essential role in the management of patients with solid tumors as they do today in hematologic oncology.

Nonrandom gain of chromosome 7 in central neurocytoma: a chromosomal analysis and fluorescence in situ hybridization study

Central neurocytoma is a benign, slow-growing neoplasm with favourable prognosis. Biomolecular analysis has failed to demonstrate significant alterations, and no cytogenetic alterations have been reported. In this study we demonstrate chromosome 7 gain in three of nine neurocytomas (33%). Traditional cytogenetic analysis performed in four of the nine cases identified trisomy 7 as the sole chromosomal abnormality in one case. Interphase cytogenetics utilizing fluorescent in situ hybridization (FISH) on cell suspensions from formalin-fixed paraffin-embedded tumour tissue performed in all nine cases detected trisomy 7 in two more cases and tetrasomy in another. Our results suggest that chromosome 7 gain is a feature of neuroectodermal tumorigenesis, possibly conferring growth advantage on the neoplastic cells. FISH on interphase nuclei is a valuable adjunct in the genetic evaluation of rare central nervous system neoplasms with low baseline proliferative activity.

Short arm of chromosome 1 aberration recurrently found in pigmented villonodular synovitis

Pigmented villonodular synovitis (PVNS) is a relatively uncommon benign lesion that is characterized by diffuse synovial proliferation, mainly occurring in knee joints. Cytogenetic reports about this lesion are few and they describe the presence of numerical and structural chromosome aberrations. We obtained PVNS tissue from the left knee joint of a 53-year-old female, and performed cytogenetic analysis. Fluorescence in situ hybridization (FISH) was also performed by using the formalin fixed, paraffin embedded PVNS tissue. Two seemingly unrelated clones were found: the first clone had structural abnormalities of chromosome 1, 3, and 18, and the second one had trisomy 7 as a sole numerical abnormality. FISH using a chromosome 7 specific alpha-satellite DNA probe revealed that interphase nuclei possessed two or three signals. We describe the clonal aberrations found in a case of PVNS. The deleted lesion of the chromosome 1 (1p10-1p31.3) includes the locus of coagulation factor III gene (1p22-p21), and the coagulation factor V (1q21-q25) locus includes another breakpoint that is 1q25. In addition, recurrent structural abnormalities at the short arm of chromosome 1 have been reported. These facts might play some role in the hemorrhagic tendency and histogenesis of these lesions.

Multiple clonal chromosome aberrations in a case of childhood focal nodular hyperplasia of the liver

A case of focal nodular hyperplasia is described that was accompanied by intense reactive stromal changes giving rise to a pseudosarcomatous appearance. Cytogenetic study revealed complex karyotypic abnormalities including five partially identifiable clonal aberrations and one marker chromosome. The composite karyotype was interpreted as: 45-46,XY,add(4)(q21-25)[24], add(11)(p14)[24], add (19)(p13)[15], der(20)t(1;20)(q25;p12)[31], add(21) (q22)[13],-22[3], +mar[2][cp31]. In addition, quadriradial or complex figures, telomeric associations tas, unidentified ring chromosomes, chromosome breaks, and markers were seen in some cells. Such cytogenetic findings, although suggestive of malignancy, could most likely be related to a nonneoplastic condition, i.e., the unusual florid reactive changes associated with this focal nodular hyperplasia.

Use of fluorescence in situ hybridization to detect loss of chromosome 10 in astrocytomas

Models describing progression in the genetic derangement of glial tumors have shown loss of chromosome 10 to occur most frequently in high-grade lesions, suggesting that identification of this loss may be prognostically significant. Fluorescence in situ hybridization (FISH) analysis may be a valuable adjunct to histological grading if it can accurately detect this loss. In this paper, the authors correlate results obtained from FISH, cytogenetic, molecular genetic, and flow cytometric analyses of a series of 39 brain specimens, including seven normal, two gliotic, and 30 neoplastic (one Grade II, one Grade III, and 28 Grade IV astrocytoma) specimens. Contiguous section of freshly resected surgical tissue were submitted for tissue culturing (karyotype) and touch preparation (FISH), snap-frozen (molecular genetic), or paraffin-embedded (histology and flow cytometry). Centromere-specific probes for chromosomes 10 and 12 were used for FISH analysis, and 19 restriction fragment length polymorphisms (two p-arm and 17 q-arm) and four microsatellite sequence polymorphisms (three p-arm and one q-arm) were used for molecular genetic analysis of chromosome 10. Findings showed FISH and loss of heterozygosity (LOH) analyses to be concordant in 33 of 38 specimens (sensitivity 94%, specificity 81%), with one specimen indeterminate on LOH analysis. Both FISH and LOH analyses were more sensitive at detecting chromosome 10 loss than conventional cytogenetic (karyotype) analysis. The authors conclude that FISH is a sensitive test for detecting chromosome 10 loss and ploidy in astrocytic tumors.

Chromosomal abnormalities in 47 pediatric brain tumors

The karyotypes of 47 pediatric brain tumors (14 cerebellar pilocytic astrocytomas, six cerebral pilocytic astrocytomas, seven anaplastic astrocytomas and glioblastomas, nine medulloblastomas [PNETs], one cerebral neuroblastoma, four ependymomas, and seven miscellaneous other neoplasms) are presented. Most of the pilocytic astrocytomas and ependymomas had normal karyotypes. In contrast, the majority of the anaplastic astrocytomas-glioblastomas were abnormal. The abnormalities included losses and structural abnormalities of chromosomes 9, 13, and 17, and double minutes. There were no losses of chromosomes 10 and 19q or gains of chromosome 7, which are among the most common abnormalities of adult glioblastomas. The chromosomal abnormalities in the medulloblastomas were similar to those reported in the literature but less frequent. Four tumors (choroid plexus papilloma, meningioma, cerebral malignant rhabdoid tumor, and immature teratoma) had losses of chromosome 22.

Absence of trisomy 7 in nonneoplastic human ascitic and pleural fluid cells. An interphase cytogenetic study

Trisomy 7 is a frequent aneuploid change in lymphomas, adenocarcinomas, and malignant mesenchymal and neurogenic tumors. Moreover, it has been observed in cultured and uncultured non-neoplastic cells from brain, kidney, liver, lung, and atherosclerotic plaques, among other tissues, opening debate on the role of this change in normal and neoplastic tissue. We used nonradioactive in situ hybridization (ISH) with a biotinylated chromosome 7-specific alpha-satellite DNA probe to seek an extra copy of chromosome 7 in ascitic and pleural fluid interphase cells from 26 donors. The donors comprised 24 patients with nonmalignant clinical history, one patient with non-Hodgkin's malignant lymphoma (positive control), and one patient with chronic myeloid leukemia (CML, negative control). The highest frequency of fluid cells with three hybridization signals in patients without neoplasia was 0.5%, in contrast to the frequency of 40.5% noted in the fluid cells of the patient with non-Hodgkin's malignant lymphoma. The results demonstrate that the frequency of trisomic cells in pleural as well as in ascitic fluid is very low, making possible use of the cells in ascitic or pleural fluids in identification of malignancy.

Clonal chromosome aberrations in a case of nodular fasciitis

We report a case of nodular fasciitis with clonal chromosome aberrations including a reciprocal t(3;15)(q21;q22) and interstitial deletion (13)(q14q21).