H3F3A K28M mutation (more commonly referred to as K27M) is a diagnostic parameter for the 2016 WHO-recognized entity, "Diffuse Midline Glioma H3 K27M-mutant", an astrocytic diffusely infiltrating tumor arising in the midline, typically within the brainstem, but also sometimes arising in the diencephalon or spinal cord. These tumors have a poor prognosis. The H3K27M alteration, which is characteristically heterozygous, leads to a decrease in overall H3K27me3 levels through dysregulation of the polycomb repressive complex 2 (PRC2), and a concurrent increase in H3K27 acetylation levels. Research is ongoing in an effort to develop ways to exploit this characteristic molecular alteration through targeted strategies.

In AML, presence of exon 17 mutations in KIT may confer an adverse prognosis or increased relapse rate. However, its significance in brain tumors is yet to be determined.

Some studies have demonstrated activity of sonic hedgehog pathway inhibitors in a subset of medulloblastomas harboring alterations in this pathway.

The anaplastic lymphoma kinase (ALK) has emerged as a potentially relevant biomarker and therapeutic target in pediatric solid and hematologic malignancies. It is a receptor tyrosine kinase (RTK) that is known to be activated either by point mutations or by chromosomal translocations. These genetic alterations act as oncogenic drivers and promote constitutive, ligand-independent activation of this RTK. Recurrent activating point mutations are seen within kinase domain in both the hereditary and sporadic form of neuroblastoma cases (7-10%). According to some studies, the presence of an ALK aberration could be a biomarker of aggressive disease and inferior clinical outcome. Clinical trials of crizotinib in neuroblastoma are underway. The R1275Q mutation is most common variant among ALK-mutated neuroblastomas (33%), and is found in both sporadic and familial cases. The R1275 amino acid substitution lies within the activation loop and causes constitutive ligand-independent activation of this RTK. Both preclinical and clinical studies suggest that this mutation could be sensitive to ALK inhibition.

IDH1 or IDH2 mutations are found in >70% of lower grade diffusely infiltrative gliomas and in >90% of secondary glioblastoma. IDH mutational status has been reported to be a favorable prognostic indicator relative to wild-type gliomas of similar histology, regardless of grade. Therapeutic strategies exploiting mutated IDH protein, including through direct inhibition and vaccine-based approaches, are currently the subject of preclinical research and clinical trials.

IDH1 or IDH2 mutations are found in >70% of lower grade diffusely infiltrative gliomas and in >90% of secondary glioblastoma. IDH mutational status has been reported to be a favorable prognostic indicator relative to wild-type gliomas of similar histology, regardless of grade. Therapeutic strategies exploiting mutated IDH protein, including through direct inhibition and vaccine-based approaches, are currently the subject of preclinical research and clinical trials.

BRAF alterations have been described in a wide spectrum of brain tumors, including in gliomas and glioneuronal tumors. BRAFV600E mutations have been found in approximately 10--15% of pilocytic astrocytoma and in approximately 5--10% of pediatric diffusely infiltrating gliomas, including diffuse astrocytomas (WHO grade II), anaplastic astrocytomas (WHO grade III) and glioblastomas (WHO grade IV), but in less than 2% of comparable adult gliomas. This mutation is potentially targetable.

CDKN2A H83Y lies within the ANK3 domain of the CDKN2A protein. H83Y confers a loss of function to the CDKN2A protein as demonstrated by loss of cell cycle control. The CDKN2A gene locus is altered in up to approximately 57% of glioblastoma, most commonly as a homozygous deletion, and frequently with concurrent deletion of the CDKN2B locus. CDKN2A/CDKN2B loss may be associated with increased sensitivity to CDK4/6 inhibitors. The efficacy and toxicity profiles of these inhibitors in the context of a variety of cancer types are currently under evaluation in clinical trials. CDKN2A mutations account for only 1-3% of glioblastomas and the clinical significance remains to be elucidated.

Somatic mutations in TP53 are frequent in human cancer. Germline TP53 mutations cause of Li-Fraumeni syndrome, which is associated with a range of early-onset cancers. The types and positions of TP53 mutations are diverse. TP53 mutations may be potential prognostic and predictive markers in some tumor types, as well as targets for pharmacological intervention in some clinical settings. The IARC TP53 Database (http://www-p53.iarc.fr/) is a useful resource which catalogues TP53 mutations found in cancer.

This gene is a known cancer gene. ARID1A/BAF250A subunit of the SWI/SNF (BAF) chromatin remodeling complex has emerged as recurrently mutated in a broad array of tumor types and a potential tumor suppressor. There is evidence indicating that ARID1A-mutated cancers may be subjected to therapeutic intervention.