| ORIGINAL ARTICLE
|Year : 2009 | Volume
| Issue : 5 | Page : 559--566
Assessment of 1p/19q status by fluorescence in situ hybridization assay: A comparative study in oligodendroglial, mixed oligoastrocytic and astrocytic tumors
Bhaskar Shukla1, Shipra Agarwal1, Vaishali Suri1, Pankaj Pathak1, Mehar Chand Sharma1, Deepak Gupta2, Bhavani Shankar Sharma2, Ashish Suri2, Ashutosh Halder3, Chitra Sarkar1
1 Department of Pathology, All India Institute of Medical Sciences, New Delhi, India
2 Department of Neurosurgery, All India Institute of Medical Sciences, New Delhi, India
3 Department of Reproductive Biology, All India Institute of Medical Sciences, New Delhi, India
Background : Due to overlapping histomorphological features, difference in clinical behavior and treatment response, establishing potential molecular markers to facilitate diagnosis of various genetic subtypes of diffuse gliomas is essential. Aim : To analyze 1p/19q status in diffuse gliomas and correlate it with epidermal growth factor receptor (EGFR) and p53 protein expression. Materials and Methods : 1p/19q status in 43 cases was evaluated by fluorescence in situ hybridization assay. Glial fibrillary acidic protein (GFAP), EGFR and p53 were assessed by immunohistochemistry. Results : Glial fibrillary acidic protein immunopositivity was observed in oligodendrogliomas within minigemistocytes and gliofibrillary oligodendrocytes as perinuclear homogenous blobs. It also highlighted the intermingled reactive astrocytes. Astrocytomas and the astrocytic component of oligoastrocytomas showed a diffuse fibrillary type of staining. 1p and/or 19q loss was seen in 65% (13/20) of oligodendrogliomas and 66.6% (5/9) of mixed oligoastrocytomas. There was one case each of pediatric oligodendroglioma and mixed oligoastrocytoma, none of which showed 1p/19q loss. None of the astrocytomas including two pediatric cases showed this alteration (P < 0.05). p53 was expressed in 57.1% of astrocytomas (8/14), 33% of mixed oligoastrocytomas (3/9) and 10% of oligodendrogliomas (2/20). Majority of oligodendrogliomas (85%; 17/20) and oligodendroglial areas in mixed oligoastrocytomas (77.7%; 7/9) showed a membranous lace-like immunopositivity with EGFR. In contrast, all astrocytomas (Grade II and III) were EGFR negative.
Conclusion : Loss of 1p/19q is strongly associated with oligodendroglial phenotype, while astrocytic tumors are more likely to show p53 over-expression. p53 expression and 1p/19q status appear to be mutually exclusive.
Department of Pathology, AIIMS, New Delhi - 110 029
Source of Support: None, Conflict of Interest: None
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