RESUMO
BRCA1, BRCA2 and other known susceptibility genes account for less than half of the detectable hereditary predisposition to breast cancer. Other relevant genes therefore remain to be discovered. Recently a new BRCA2-binding protein, PALB2, was identified. The BRCA2-PALB2 interaction is crucial for certain key BRCA2 DNA damage response functions as well as its tumour suppression activity. Here we show, by screening for PALB2 mutations in Finland that a frameshift mutation, c.1592delT, is present at significantly elevated frequency in familial breast cancer cases compared with ancestry-matched population controls. The truncated PALB2 protein caused by this mutation retained little BRCA2-binding capacity and was deficient in homologous recombination and crosslink repair. Further screening of c.1592delT in unselected breast cancer individuals revealed a roughly fourfold enrichment of this mutation in patients compared with controls. Most of the mutation-positive unselected cases had a familial pattern of disease development. In addition, one multigenerational prostate cancer family that segregated the c.1592delT truncation allele was observed. These results indicate that PALB2 is a breast cancer susceptibility gene that, in a suitably mutant form, may also contribute to familial prostate cancer development.
Assuntos
Neoplasias da Mama/genética , Mutação/genética , Proteínas Nucleares/genética , Neoplasias da Próstata/genética , Proteínas Supressoras de Tumor/genética , Adulto , Idoso , Alelos , Análise Mutacional de DNA , Proteína do Grupo de Complementação N da Anemia de Fanconi , Feminino , Finlândia , Predisposição Genética para Doença/genética , Humanos , Masculino , Pessoa de Meia-Idade , Proteínas Nucleares/química , Proteínas Nucleares/metabolismo , Linhagem , Deleção de Sequência/genética , Proteínas Supressoras de Tumor/química , Proteínas Supressoras de Tumor/metabolismoRESUMO
BACKGROUND: About 5-10% of breast cancer is due to inherited disease predisposition. Many previously identified susceptibility factors are involved in the maintenance of genomic integrity. AATF plays an important role in the regulation of gene transcription and cell proliferation. It induces apoptosis by associating with p53. The checkpoint kinases ATM/ATR and CHEK2 interact with and phosphorylate AATF, enhancing its accumulation and stability. Based on its biological function, and direct interaction with several known breast cancer risk factors, AATF is a good candidate gene for being involved in heritable cancer susceptibility. METHODS: Here we have screened the entire coding region of AATF in affected index cases from 121 Finnish cancer families for germline defects, using conformation sensitive gel electrophoresis and direct sequencing. RESULTS: Altogether seven different sequence changes were observed, one missense variant and six intronic ones. Based on the in silico analyses of these sequence alterations, as well as their occurrence in cases and controls, none of them, however, were predicted to be pathogenic. CONCLUSIONS: To our knowledge, this is the first study reporting the mutation screening of the AATF gene in familial breast cancer cases. No evidence for the association with breast cancer was observed.