Table 2.
Gene fusions involving members of the MAPK pathway including BRAF and in which low-grade gliomas the fusions have been identified.
| MAPK pathway gene | Gene fusion | Exon variant | Tumors fusion is present in | WHO grade | Reference |
|---|---|---|---|---|---|
| BRAF | KIAA1549:BRAF | exons 16:9, exons 15:9, exons 16:11 | PA, PMA, PXA, GG, SGCA, DA (A and ODG) | I, II | (9, 13, 15, 24, 32, 34) |
| BRAF | KIAA1549:BRAF | exons 15:8 | PA | I | (12) |
| BRAF | KIAA1549:BRAF | exons 16:10 | PA | I | (26) |
| BRAF | KIAA1549:BRAF | exons 15:11, exons 17:10 | PA, LGG | I, II | (27) |
| BRAF | KIAA1549:BRAF | exons 18:10 | PA | I | (9, 13) |
| BRAF | KIAA1549:BRAF | exons 19:9 | PA | I | (13) |
| BRAF | FAM131B:BRAF | exons 2:9, exons 3:9, exons 2:10 | PA | I | (12) |
| BRAF | FXR1:BRAF | Not reported | DA | II | (19) |
| BRAF | BRAF:MACF | Not reported | GG | II | (19) |
| RAF1 | SRGAP3:RAF1 | exons 12:10 | PA | I | (16) |
| RAF1 | SRGAP3:RAF1 | exons 12:7, exons 11:9 | PA | I | (12) |
| RAF1 | SRGAP3:RAF1 | exons 11:8 | PA | I | (13) |
| RAF1 | QK1:RAF1 | Not reported | PA | I | (19) |
PA, pilocytic astrocytoma; PMA, pilomyxoid astrocytoma; PXA, pleomorphic astrocytoma; DA, diffuse fibrillary astrocytoma; A, grade II astrocytoma not further specified; GG, ganglioglioma; SGCA, subependymal giant cell astrocytoma; ODG, oligodendroglioma; LGG, low-grade gliomas not further specified. A and ODG were found to have the KIAA1549:BRAF fusion in 6 of 118 cases and were thought to be misdiagnosed PA as they all followed a particularly benign clinical course (15).