Breast cancer remains the most common cancer affecting women in the Western world. Although most breast cancers are sporadic, ϳ10% are inheritable and associated with mutations in at least two loci, BRCA1 and BRCA2. The BRCA1 gene is located at position 17q21 of the human genome, and mutations in this gene are associated with an increased risk of development of breast and ovarian cancer (1). The BRCA1 gene encodes a protein of 1864 amino acid residues that is primarily located in the nucleus (2). The BRCA1 gene product contains several domains that may effect its interaction with many other cellular proteins. The N terminus includes a domain presumably involved in the formation of homodimers and heterodimers (with the BARD1 protein) and a ring finger domain that is involved in interaction with BAP1 and E2F-1; the middle portion of BRCA1 contains a nuclear localization signal and domains that can bind to c-Myc, p53, pRB, and the DNA repair proteins RAD50 and RAD51; the C terminus includes two BRCT domains that interact with multiple factors involved in transcriptional regulation, including CtIP, p300, p53, pRB, CBP, BRCA2, RNA polymerase II, and RNA helicase A (3, 4). Recent studies suggest that the BRCA1 protein may be involved in regulating numerous cellular functions including DNA damage repair, gene transcription, chromosome segregation, cell cycle arrest, and apoptosis (4).Several studies suggest a role for BRCA1 in DNA repair. First, BRCA1 interacts with RAD51, a human homologue of the yeast RecA protein involved in double-stranded DNA break repair (5, 6). In vitro, BRCA1 can associate with the RAD50-MRE11-NBS1 complex, a functional unit implicated in homologous recombination, non-homologous end joining, and meiotic recombination. In irradiated cells, BRCA1 is recruited to this complex, where it likely plays a role in DNA repair (7). Moreover, ectopic expression of BRCA1 decreases cellular sensitivity to radiation and increases the efficiency of DNA break repair (8). Second, BRCA1 interacts with proteins involved in mismatch repair, mainly MSH2, MSH3, and MSH6. Furthermore, the association of BRCA1 with MSH2 and MSH6 was found to be essential for transcription-coupled DNA repair (9). A recent study by Wang et al. (9) provides evidence for the existence of a large BRCA1-containing complex that incorporates factors involved in various types of DNA repair. The identified complex was found to contain BRCA1 and the DNA repair factors MSH2, MSH6, MLH1, ATM, BLM, RAD50, MRE11, NBS1, and replication factor C (9). These results suggest that BRCA1 might provide a scaffold that functions in coordinating multiple activities required for the maintenance of genomic integrity and the fidelity of DNA replication (9).Besides DNA repair function, numerous studies also suggest that BRCA1 might play an important role in transcriptional regulation. BRCA1 physically interacts with key enzymes involved in transcription, mainly RNA polymerase II and RNA helicase A, suggesting that it might be a component of the transcriptional ma...

could not be reached. The first author identified some issues and brought them to the attention of the Journal. Subsequently, some issues were also noted in the article by the Journal. After careful analysis of all of the original data used for preparing the figures in the publication, the following errors were identified: The Actin immunoblot in the original Fig. 1A (identified from MCF-7) was used in the immunoblot for Fig. 6C (ERK1/2, lanes 3-4). In Fig. 2B (left panel, MCF7 cells), the Actin immunoblots for Ad.Control and Ad.BRCA1 were incorrect. The authors state that the Actin immunoblot for Ad.Control and Ad.BRCA1-infected MCF7 cells in Fig. 2B should have used the same Actin immunoblot depicted in Fig. 3 for MCF-7 cells infected with Ad.Control and Ad.BRCA1 as the results shown in Fig. 2B and Fig. 3 used the same set of lysates that were also probed for PARP (Fig. 2B) and Fas-L and Fas (Fig. 3). The JNK immunoblot in Fig. 4 (MCF-7) was reused as the Actin immunoblot in Fig. 4 (right panel) and the Actin immunoblot in Fig. 5E. The authors state that the top label for Fig. 7 (left panel) was incorrect and should have used the same top label shown in Fig. 5C. Both Figs. 5C and 7 (left panel) depict results obtained from the same MCF7 cell lysates infected with Ad.Control or Ad.BRCA1 in the presence (ϩ) or absence (Ϫ) of PD98059. The Actin immunoblots depicted in Fig. 6C and in Fig. 7 (right Panel) were incorrect. The correct immunoblots for all of these figures listed above were found and submitted to the Journal. Given these errors, the withdrawing authors state that the responsible course of action would be to withdraw the article to maintain the high standards and rigor of scientific literature from the withdrawing authors' group as well as the Journal. However, the withdrawing authors state that these errors do not change the underlying scientific findings of the article.