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Intronic deletion affecting a negative regulatory region of TP73 is related to breast and colorectal carcinomas
Author(s) -
Peña Cristina,
Garcia Jose M.,
Dominguez Gemma,
Silva Javier,
Garcia Vanesa,
Carcereny Enric,
Vargas Javier,
Provencio Mariano,
España Pilar,
Bonilla Felix
Publication year - 2004
Publication title -
genes, chromosomes and cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.754
H-Index - 119
eISSN - 1098-2264
pISSN - 1045-2257
DOI - 10.1002/gcc.10322
Subject(s) - allele , loss of heterozygosity , biology , exon , colorectal cancer , intron , microsatellite , gene , haploinsufficiency , microbiology and biotechnology , genetics , single strand conformation polymorphism , cancer research , cancer , phenotype
The TP73 gene encodes a nuclear protein that has high homology with TP53 . TP73 is rarely mutated in human cancer. The presence of a 1‐kb regulatory fragment within the first intron of TP73 was recently reported. This fragment exerts silencer activity on TP73 mediated by ZEB. We searched for possible mutations in this negative regulatory region in 45 colorectal and 43 breast cancer patients and in 34 healthy donors. The study was carried out using the SSCP method, and the allelic variants detected were sequenced. The expression of TP73 was analyzed by quantitative RT‐PCR, and loss of heterozygosity (LOH) was assessed by microsatellite study. In several samples, we identified an allele variant that corresponds to a deletion of 73 bp in tumor tissues and normal counterparts, localized between −489 and −417 from the ATG start site of exon 2. Among the 88 tumor samples, 35 (40%) showed at least 1 allele with the cited deletion, versus 7 of the 34 (21%) healthy donors ( P = 0.045). When we classified the patients according to the number of variations into homozygous or heterozygous groups, the significance was clearer ( P = 0.03). No LOH was detected in the heterozygous cases. There was a positive quantitative correlation between the expression of TP73 and the presence of the allelic variant ( P = 0.029). These data suggest that this allelic variant is common in breast and colorectal cancers and that it could alter the expression of the TP73 gene with an additive effect. © 2004 Wiley‐Liss, Inc.