Interphase Cytogenetic (In Situ Hybridization) Analysis of Astrocytomas Using Archival, Formalin-Fixed, Paraffin-Embedded Tissue and Nonfluorescent Light Microscopy

Abstract

Astrocytomas contain nonrandom chromosomal abnormalities that recently have been correlated with shortened patient survival. Two frequently reported aberrations are trisomy 7 and monosomy 10.We assessed the numerical complement of chromosomes 7 and 10 in formalin-fixed, paraffin-embedded brain biopsy tissue from 28 diffuse astrocytomas by in situ hybridization using a nonfluorescent enzymatic detection system. Clinical follow-up of at least 5 years was available in 26 cases (93%).Monosomy 10 was identified in 7 cases (25%): astrocytoma, 1 case; anaplastic astrocytoma, 1 case; and glioblastoma, 5 cases.Cytogenetic studies have revealed consistent nonrandom numerical and structural chromosomal abnormalities in astrocytic neoplasms. Two recent studies at the Mayo Clinic (Rochester, Minn) have demonstrated prolonged survival of patients with a normal tumor karyotype compared with those exhibiting clonal aberrations, 1 ' 2 suggesting that cytogenetic analysis may provide useful diagnostic and prognostic information for patients with central nervous system malignancies. Common numerical changes in diffuse astrocytomas include gains of chromosome 7 and losses of chromosomes 10, 22, X, and Y, whereas structural abnormalities most frequently involve chromosomes 1 and 9.2-7 Furthermore, molecular genetic and cytogenetic studies provide evidence for an orderly M a n u s c r i p t received A u g u s t 6, 1996; revision accepted December 11,1996.Address reprint requests to Dr White: Department of Pathology, Division of Neuropathology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, Dr Tonk is now with the Department of Pediatrics, Texas Tech University Health Science Center, Lubbock, Texas.Trisomy 7 was identified in 11 cases (39%): astrocytoma, 5 cases; glioblastoma, 6 cases. Multivariate analysis revealed that monosomy 10 was the most statistically significant negative predictor of patient survival.Numerical chromosomal abnormalities are detectable in astrocytomas in archival tissue using interphase cytogenetics and nonfluorescent light microscopy. Although larger studies are required, our data suggest that potentially useful prognostic information may be obtained with this approach.

Chromosomes 7,17 Polysomies and Overexpression of Epidermal Growth Factor Receptor and p53 Protein in Epithelial Hyperplastic Laryngeal Lesions

“…In our study, large tissue samples after laryngectomies and small diagnostic biopsy specimens were used. The most critical part of the ISH procedure is proteolytic digestion, which should not be individualized only for different tissue samples, but even different areas within the same slice may demand different digestion conditions [19, 25, 26]. An additional drawback of ISH is that a focal loss of chromosomes, unlike gains, may possibly be missed, since a small percentage of nuclei contain only one or no hybridization signal [27].…”

Molecular Diagnostics in Central Nervous System Tumors

“…18,22,23 Second only to gains on chromosome 7, losses involving chromosome 10 are quite frequent in astrocytomas, limited mainly to high-grade tumors. 24,25 Most of CGH and FISH studies to date have identified 10q loss/monosomy 10 as an independent predictor of shorter patient survival [24][25][26][27] ; in only rare instances has this association not reached statistical significance in multivariate models. [28][29][30] Several candidate tumor suppressor genes have been mapped to 10q, including PTEN (10q23), DMBT1 (10q25.3-26.1), and more recently annexinVII (ANX7; 10q21).…”

Cytogenetic Analysis of Gemistocytic Cells in Gliomas

“…Frequently, nonrandom karyotypic aberrations including over-representation of chromosome 7 and loss of chromosome 10 are found in astrocytoma, mixed oligoastrocytoma, and oligodendroglioma (19,24,25). Monosomy 10, confined to high-grade tumors and a predictor of poor patient survival (25), cannot simply be related to PTEN gene mutations on 10q23, as such mutations are rare in these tumors (14).…”

“…Monosomy 10, confined to high-grade tumors and a predictor of poor patient survival (25), cannot simply be related to PTEN gene mutations on 10q23, as such mutations are rare in these tumors (14). Trisomy 7 has been consistently found in gliomas.…”