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A deletion polymorphism due to alu‐alu recombination in intron 2 of the retinoblastoma gene: Association with human gliomas
Author(s) -
Rothberg Paul G.,
Ponnuru Satish,
Baker Darren,
Bradley John F.,
Freeman Arnold I.,
Cibis Gerhard W.,
Harris David J.,
Heruth Daniel P.
Publication year - 1997
Publication title -
molecular carcinogenesis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.254
H-Index - 97
eISSN - 1098-2744
pISSN - 0899-1987
DOI - 10.1002/(sici)1098-2744(199707)19:2<69::aid-mc1>3.0.co;2-g
Subject(s) - biology , retinoblastoma , alu element , exon , genetics , intron , allele , glioma , microbiology and biotechnology , tumor suppressor gene , gene , cancer research , carcinogenesis , human genome , genome
The retinoblastoma gene ( RB ) encodes a tumor suppressor that is inactivated in a number of different types of cancer. We searched for gross alterations of this gene in tumors of the central nervous system by using Southern blot hybridization. A common alteration was found in several tumors and was mapped to the region around exon 2. Nucleotide sequencing showed that the alteration was caused by a 799‐bp deletion in intron 2 of the RB gene and was probably due to homologous recombination between two Alu repeats. Deletions of this type have not been found previously in the RB gene. The deletion turned out to be a polymorphism with an allele frequency estimated at 2.2% in 185 patients without cancer. The deletion was foud in five of 48 patients with brain tumors (allele frequency of 5.2%). This difference is not statistically significant ( P = 0.149, Fishers exact test). Confining the analysis only to glioma brain tumors revealed a statistically significant difference compared with the cancer‐free patient controls ( P = 0.027, Fishers exact test). Further study is needed to determine if the deletion is a weak brain cancer–predisposing mutation or a harmless polymorphism. Finding this mutation in a tumor and the germline DNA of a retinoblastoma patient could lead to incorrect estimation of the heritability of a tumor. Mol. Carcinog. 19:69–73, 1997. © 1997 Wiley‐Liss, Inc.