Diagnostic and prognostic markers in gliomas – an update

Abstract

Gliomas are the most common primary central nervous system tumour seen in adults. There have been many advances over the last two decades as we widen our search for a molecular basis of gliomagenesis. Many biomarkers have been discovered to be important in the management of gliomas, including 1p19q co-deletion, MGMT promoter methylation, BRAF and IDH1 mutations. In this review, we attempt to summarise the available literature on these biomarkers and their use in the diagnosis and management of gliomas. We pay special attention to the recently discovered IDH1 mutation, which is already proving to be a valuable new marker for favourable prognosis and may also indicate a greater response to therapy. 1p19q co-deletions have been shown to delineate a clinically distinct tumour type and are now routinely tested for in certain situations and can help direct treatment. MGMT promoter methylation is one of the most commonly studied biomarkers in gliomas. It has been shown to be a strong positive prognostic marker in gliomas, with positive tumours being more sensitive to chemotherapy. However, a lack of alternatives means that it is not yet a routine mutation tested for clinically. BRAF mutations are new markers found in pilocytic astrocytomas. Although the prognostic value of such mutations is not yet known, they may play a significant role in the diagnosis and treatment of such tumours. IDH1 mutations are 'the new kid on the block' and seem to play a central role in the pathogenesis of gliomas. They represent an independent and favourable prognostic marker and are a new molecular marker for disease diagnosis. Its role in determining response to chemotherapy is still controversial but with further study, IDH1 mutations may prove to be an invaluable marker in the management of gliomas.

Prognostic value of MGMT methylation in colorectal cancer: a meta-analysis and literature review

“…Therefore, MGMT is critical for the protection of normal cells from exogenous carcinogens. Its inactivation by promoter hypermethylation plays an important role in tumorigenesis in several types of tumors including CRC [8][9][10][11][12][13]. An ideal study designed to address this question would be to perform a serial analysis of the whole process from adenoma to carcinoma.…”

Importancia de la mutación de la isocitrato deshidrogenasa tipo I como factor pronóstico en pacientes con glioblastomas y revisión de la literatura

“…Pero no se ha observado este marcador en otros tumores del sistema nervioso central como neurocitomas, ependimomas, astrocitoma pilocítico y meduloblastoma entre otros 2,19 .…”

“…En la literatura está descrito un aumento de la supervivencia global y tiempo libre de la enfermedad después de la cirugía en paciente portadores de la mutación de la IDH1 2,7,11,14,17,21,[30][31][32][33] . La supervivencia media varía entre los 16 a 42,9 meses según los estudios consultados 2,7,11,14,17,21,[30][31][32][33] .…”

“…Los GBM pueden dividirse en primarios (de novo) y secundarios. Los GBM primarios corresponden aproximadamente al 90-95% y característicamente son pacientes mayores de 40 años, presentan un curso clínico agresivo y una mortalidad cercana al 98-100% [1][2][3][4][5] . Los GBM secundarios característicamente derivan de gliomas de menor grado y representan aproximadamente un 5-10% de los GBM, se diagnostica en pacientes más jóvenes, con un curso clínico más larvado y presentan una mejor respuesta a tratamiento 1,6,7 .…”

Microfluidics for rapid detection of isocitrate dehydrogenase 1 mutation for intraoperative application

“…12,21 Patients with malignant astrocytoma with IDH1 mutations have nearly twice as long, or even 10 times longer, median overall survival compared with those without mutations. 3,34 A recent study also revealed that refinement of the classification of the 3 most common types of brain tumors could be achieved by telomerase reverse transcriptase promoter and IDH1 mutation status.…”