title: A subset of human gliomas shows over-expression of KIT without its amplification.
abstract: Receptor tyrosine kinase (RTK) encoded by proto-oncogene KIT is known to be involved in different types of cancers. Reportedly, KIT expression has been associated with higher grade of gliomas. Initial RT-PCR based KIT expression observed in low grade glioma cases evoked our interest to ascertain its status in glioma patients who underwent resection during 2008-2009. Contrary to earlier reports, over-expression of the RTK was observed in 32.5% glioma cases across low/high grades (n=40). Using quantitative PCR (qPCR), an up-regulation of the receptor (KIT) and its ligand (KITLG) was detected in most of the immunopositive cases at the transcript level. Sequence analysis of KIT showed two nucleotide substitutions in exons 10 and 17, in 4 and 2 cases, respectively though their pathological significance remained unclear. qPCR detected gene amplification in 2/13 glioma and allele loss in 1/13 glioma cases. This was in accordance with FISH results of these KIT positive neoplastic tissues. The data suggest that deranged expression of KIT is independent of gene amplification (p>0.05). Aberrant KIT expression is significantly associated with transcriptional up-regulation (p<0.001), though the precise mechanism(s) for transcriptional activation remain unclear.
authors.affiliation: National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, India. masum@nii.ac.in
authors.forename: Masum
authors.initials: M
authors.lastname: Saini
authors.forename: Ajaya Nand
authors.initials: AN
authors.lastname: Jha
authors.forename: Andleeb
authors.initials: A
authors.lastname: Abrari
authors.forename: Sher
authors.initials: S
authors.lastname: Ali
mesh_terms: D000328:Adult; D000368:Aged; D022981:Allelic Imbalance; D001932:Brain Neoplasms / Q000201:enzymology* / Q000235:genetics* / Q000473:pathology; D005091:Exons; D005260:Female; D005784:Gene Amplification; D005910:Glioma / Q000201:enzymology* / Q000235:genetics* / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D000090063:Proto-Oncogene Mas; D019009:Proto-Oncogene Proteins c-kit / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D017422:Sequence Analysis, DNA / Q000379:methods; D015854:Up-Regulation; D055815:Young Adult
chemical_list: C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; D019009:Proto-Oncogene Proteins c-kit