Читать книгу Intracranial Gliomas Part II - Adjuvant Therapy - Группа авторов - Страница 13

In 1926 Percival Bailey and Harvey Cushing presented the first classification of gliomas based on the presumed developmental tree of the central nervous system (CNS) [1]. This cell lineage-oriented concept has long been a central basis of the World Health Organization (WHO) classification of CNS tumors. Despite regular updates according to new information on histology, immunohistochemistry (IHC), and ultrastructure, even in its 4th edition published in 2007 [2, 3] this classification outlined only the histogenetic profile of each neoplasm.

Nonetheless, it is now clear that neuroepithelial tumors have the potential to differentiate beyond the presumed developmental tree of the CNS and that various lineages of differentiation do not necessarily correlate with the biological behavior of the mass lesion [4]. Moreover, characterization of gliomas based on descriptive histological criteria has been always accompanied by more or less considerable interobserver variability, especially in cases of mixed and heterogeneous neoplasms, caused by subjective interpretation of the microscopic tumor appearance and/or small volume of the biopsy material [5, 6]. Finally, the impact of tumor pathology on clinically related parameters (e.g., response to therapy or survival) may be frequently much better predicted by genetics, than by histological characteristics [5, 7–9]. Therefore, solely cell lineage-oriented classification of gliomas appears to no longer be rational and an alternative approach for typing and grading of brain tumors based on molecular information has thus been sought [4].

To discuss the incorporation of genetic data into the next edition of the WHO classification, a consensus meeting of neuropathologists with an expertise in molecular diagnosis was held in May 2014 in Haarlem, the Netherlands, under the sponsorship of the International Society of Neuropathology (ISN) [10]. Established “ISN-Haarlem consensus guidelines” were reflected in part in the updated WHO classification of CNS tumors (2016) [11], which considers not only phenotype, but also some genetic fingerprints of the neoplasms. This chapter presents contemporary concepts of the histopathological classification of gliomas based on the current WHO criteria and their possible future modification reflecting diagnostic, prognostic, and predictive values of major molecular alterations in tumors.