LGG-08. PILOCYTIC ASTROCYTOMAS, EXHIBIT DIFFERENTIAL AGE-BASED PATTERNS OF BRAFV600E AND BRAF GENE FUSIONS ACROSS DIFFERENT LOCATIONS. Issue 2 (22nd June 2018)

• Record Type: Journal Article
• Authors: Barange, Mukesh; Gurav, Mamta; Kurani, Hetakshi; Shetty, Omshree; Shetty, Prakash; Moiyadi, Aliasgar; Sahay, Ayushi; Goda, Jayant Sastri; Krishnatry, Rahul; Chinaswamy, Girish; Gupta, Tejpal; Jalali, Rakesh; Epari, Sridhar
• Is Part Of: Neuro-oncology. Volume 20:Issue 2(2018)supplement 2
• Page Start: i105
• Page End: i106
• Publication Date: 2018-06-22
• Subjects: Brain Neoplasms -- Periodicals; Brain -- Tumors -- Periodicals; Brain -- Cancer -- Periodicals; Nervous system -- Cancer -- Periodicals; 616.99481
• DOI: 10.1093/neuonc/noy059.350
• Languages: English
• ISSNs: 1522-8517

Abstract

Abstract: INTRODUCTION: Pilocytic astrocytomas (PCA) are characterised by BRAF fusions and V600E mutation. MATERIAL and METHODS: FFPE tissues of PCA diagnosed during 2011-17 were evaluated for BRAFV600E mutation by Sanger sequencing and KIAA1549:BRAF fusion transcripts ( KIAA1549:BRAF 16-9, KIAA1549:BRAF 15-9 and KIAA1549:BRAF 16-11 ) by reverse transcriptase polymerase chain reaction. RESULTS: 272 cases of PCA of age range 1-46 years (≤14 years:176; 15-25 yrs:76, 26-39yrs:19 and >39yrs:1) formed the sample. BRAFV600E and fusions were mutually exclusive. 25 of 234 (10.7%) were BRAFV600E mutated [cerebellum: 9/90(10%), suprasellar: 5/30(17%), CH: 4/27(15%), brain stem: 2/14(14%) and thalamic: 2/13(15%) 4th ventricle: 1/10 (10%) and 3rd ventricle: 2/7 (28.6%). Whereas 75 of 224 (33.5%) were BRAF fusion [ KIAA1549-BRAF 16-9 (n: 52), 15-9 (n:15) & 16-11 (n:8)] positive. 40% of cerebellar (36/91), 37% of suprasellar (10/27), 43% of brain stem (6/14), 36% of spinal (5/14), 21% of CH (5/24), 21% of ON (4/19), 27% of thalamic (3/11), 55.6% of 4th ventricle (5/9) and 50% of pineal (1/2) were fusion positive. None of the 19 ON cases showed BRAFV600E . It was also not detected in <3 yrs and >25 yrs age; but was seen in 15.4% (10/65) of cases in 15-25yrs. BRAF fusions were more common in ≤14 yrs (57/145; 39%). Interestingly, none of cases >30 years showed BRAF alterations. Two cases were associated with NF-1 both were negative for BRAF alterations. CONCLUSIONS: BRAF fusions are common than BRAFV600E in PCA across all locations and interestingly both are extremely rare >30years.