Events in CNS Tumor Pathology Post-2016 WHO CNS: cIMPACT-NOW Updates and Other Advancements: A Comprehensive Review Plus a Summary of the Salient Features of 2021 WHO CNS 5

Abstract

Introduction The 2016 World Health Organization Classification (WHO) of Tumors of the Central Nervous System (CNS) represented a major change. It recommended an “integrated diagnosis” comprising histologic and molecular information facilitating a more precise diagnosis of specific CNS tumors. Its goal was to provide greater diagnostic precision and reproducibility resulting in more clinical relevance and predictive value, ultimately leading to better patient care. Advances in molecular classification, mostly resulting from DNA methylation array profiling of CNS tumors, were occurring at a very rapid pace and required more rapid integration into clinical practice. Methods cIMPACT-NOW updates and other recent papers plus salient features of 2021 WHO CNS5 in this comprehensive write-up were reviewed. Results CNS tumor classification needs to be updated at a rapid pace and mechanisms put into place to guide diagnosticians and clinicians in the interim period if major changes in the classification of tumor types came to light. Recognizing the need to integrate these into clinical practice more rapidly and without inordinate delay, the International Society of Neuropathology (ISN) 2016 sponsored an initiative called cIMPACT-NOW. Discussion and/or Conclusion Goal of cIMPACT-NOW was to provide clarification regarding contentious issues arising in the wake of the 2016 WHO CNS update as well as report new advancements in molecular classification of CNS tumors and new tumor entities emerging as a result of these advancements. cIMPACT-NOW updates: It thus laid the foundation for the 5th edition of the WHO Classification of CNS tumors (2021 WHO CNS 5). We have discussed cIMPACT updates in detail in this review. In addition, molecular diagnostics including DNA methylation-based classification of CNS tumors and the practical use of molecular classification in the prognostication and treatment of CNS tumors is discussed. Finally, the salient features of the new CNS tumor classification are summarized.

Nanoparticles for efficient drug delivery and drug resistance in glioma: New perspectives

“…According to the theory of clonal evolution, the accumulation of successive mutations within a cell leads to its extracellular proliferation, and these extracellular proliferations grow abnormally as a result of selection pressure from the microenvironment. Hypermutation is the mutation of specific genes in tumor cells, resulting in reduced sensitivity to drugs 58,59 . Immune evasion is the avoidance of tumor cells being recognized and attacked by the immune system, for example by suppressing the immune response.…”

“…Hypermutation is the mutation of specific genes in tumor cells, resulting in reduced sensitivity to drugs. 58 , 59 Immune evasion is the avoidance of tumor cells being recognized and attacked by the immune system, for example by suppressing the immune response. Gliomas reside in the brain and were previously thought to be immunologically privileged and immune surveillance spared, but recent studies have shown that the brain is an active regulatory point of immune surveillance.…”