Identification and characterization of missense alterations in the BRCA1 associated RING domain (BARD1) gene in breast and ovarian cancer

Abstract

Background: BRCA1 associated RING domain protein (BARD1) was originally identified due to its interaction with the RING domain of BRCA1. BARD1 is required for S phase progression, contact inhibition and normal nuclear division, as well as for BRCA1 independent, p53 dependent apoptosis. Methods: To investigate whether alterations in BARD1 are involved in human breast and ovarian cancer, we used single strand conformation polymorphism analysis and sequencing on 35 breast tumours and cancer cell lines and on 21 ovarian tumours. Results: Along with the G2355C (S761N) missense mutation previously identified in a uterine cancer, we found two other variants in breast cancers, T2006C (C645R) and A2286G (I738V). The T2006C (C645R) mutation was also found in one ovarian tumour. A variant of uncertain consequence, G1743C (C557S), was found to be homozygous or hemizygous in an ovarian tumour. Eleven variants of BARD1 were characterised with respect to known functions of BARD1. None of the variants appears to affect localisation or interaction with BRCA1; however, putative disease associated alleles appear to affect the stability of p53. These same mutations also appear to abrogate the growth suppressive and apoptotic activities of BARD1. Conclusions: These activities allowed us to identify one of the rare variants (A2286G; I738V) as a neutral polymorphism rather than a detrimental mutation, and suggested that G1743C (C557S) is not a polymorphism but may contribute to the cancer phenotype.

Mutations in 12 genes for inherited ovarian, fallopian tube, and peritoneal carcinoma identified by massively parallel sequencing

“…These genes are BARD1, BRIP1, CHEK2, MRE11A, NBN, and RAD50. Previous reports linking BARD1 and BRIP1 with ovarian cancer were based on missense variants of unknown consequence (21,22), whereas patients in this series carry mutations in these genes with definitive loss of function.…”

Identification of Domains of BRCA1 Critical for the Ubiquitin-Dependent Inhibition of Centrosome Function

“…BARD1 interacts with BRCA1 through the RING domains of the two proteins, although there is evidence from our lab that these two proteins have additional stabilizing interactions in domains distal to the RING fingers (18). Unlike BRCA1, BARD1 mutations in breast cancer are much less frequent (19,20). Most of the functions of BARD1 are associated with BRCA1.…”

Cancer predisposing missense and protein truncatingBARD1mutations in non-BRCA1orBRCA2breast cancer families

“…Mutation reports about BARD1 mention mostly missense mutations, a few silent mutations and one in-frame deletion [Thai et al, 1998;Ghimenti et al, 2002;Ishitobi et al, 2003;Karppinen et al, 2004;Sauer and Andrulis, 2005;Vahteristo et al, 2006;Huo et al, 2007;Gorringe et al, 2008], but obvious deleterious BARD1 germline mutations (e.g. protein truncating mutations) have not been found till now.…”

“…However, we experienced that the accuracy of a PCR based mutation detection technique (even direct sequencing) strongly depends on the correct design of the primers. In our initial PCR experiments for exon 6 we used primers reported in literature [Thai et al, 1998;Ghimenti et al, 2002;Ishitobi et al, 2003;Sauer and Andrulis, 2005;Gorringe et al, 2008], but obtained biased genotypes. In fact, recurrent intron polymorphisms located at the level of the primer annealing sequences resulted in preferential amplification of the allele presenting no mismatch with the primer sequence in heterozygote individuals.…”