Original article Loss of genetic material within 1p and 19q chromosomal arms in low grade gliomas of central nervous system

Abstract

Diffuse gliomas can constitute up to one third of all gliomas diagnosed in neurosurgical centers. Their invasive growth, progression to more malignant lesions, and the lack of standardized management guidelines render a significant clinical problem. The discovery of 1p and 19q chromosomal arms deletion in neoplastic cells will probably influence both more objective diagnosis and more accurate prediction of chemotherapy response. Defining the above mentioned deletion is becoming a standard procedure in Western European countries and in the USA when LGG is diagnosed. As a result an attempt has been made to detect deletion using fluorescence in situ hybridization and to determine its prognostic value. Genetic material from 34 grade II gliomas was examined. Separate 1p and 19q deletions were discovered in 14 and 16 cases respectively. Simultaneous occurrence of both was observed in 12. The frequency of occurrence of simultaneous deletions 1p and 19q varied based on histopathological diagnosis. This disorder was not observed in astrocytomas, in oligoastrocytomas it appeared in 50% cases. The highest incidence of deletion was noted in oligodendrogliomas and amounted to 66.7%, p < 0.005. Median survival in patients with diagnosed 1p and 19q deletion in their neoplastic cells is twice longer in comparison with patients in whom no such deletion was observed (80 months vs. 41 months, p < 0.05). Frontal location of a tumor occurred to be a statistically significant factor unfavorable for prognosis, p < 0.05. In the work presented the fluorescence in situ hybridization was successfully applied to identify deletion 1p/19q. Its incidence depends on the type of diagnosed glioma. Deletions also have prognostic significance in the test group what constitutes the basis for inclusion of determining deletion 1p/19q into diagnostic and treatment algorithm in LGGs.