The present invention relates generally to the field of human genetics. Specifically, the present invention relates to methods and materials used to isolate and detect a human breast and ovarian cancer predisposing gene (BRCA1), some mutant alleles of which cause susceptibility to cancer, in particular breast and ovarian cancer. More specifically, the invention relates to germline mutations in the BRCA1 gene and their use in the diagnosis of predisposition to breast and ovarian cancer. The present invention further relates to somatic mutations in the BRCA1 gene in human breast and ovarian cancer and their use in the diagnosis and prognosis of human breast and ovarian cancer. Additionally, the invention relates to somatic mutations in the BRCA1 gene in other human cancers and their use in the diagnosis and prognosis of human cancers. The invention also relates to the therapy of human cancers which have a mutation in the BRCA1 gene, including gene therapy, protein replacement therapy and protein mimetics. The invention further relates to the screening of drugs for cancer therapy. Finally, the invention relates to the screening of the BRCA1 gene for mutations, which are useful for diagnosing the predisposition to breast and ovarian cancer.

The association between the presence of one or more rare (infrequent) alleles of the HRAS variable tandem repeat (VTR) polymorphism and the incidence of ovarian cancer in women who harbor a BRCA1 mutation can be used for evaluating risk of ovarian cancer in a human patient. The patient is tested for the presence of a mutation in the BRCA1 gene; and to determine the polymorphic form of the HRAS1 variable tandem repeat region. The presence of both a mutation in the BRCA1 gene and a rare polymorphic form of the HRAS1 variable tandem repeat region is indicative of an elevated risk of developing ovarian cancer. A kit for performing this evaluation includes reagents necessary for performing a test for the BRCA1 mutation and to evaluate the polymorphic form of the HRAS1 variable tandem repeat region.

Therapeutic methods for the treatment of prostate cancer are described. The methods include a gene therapy method for prostate cancer using the BRCA family of genes, including the BRCA1 and BRCA2 genes. The BRCA family of gene products inhibit the growth and tumorigenesis of prostate cancer cells. Therapeutic methods using the BRCA family of gene products are also described.

Recent evidence indicates that the carboxy-terminal region of the tumor suppressor protein BRCA1 is a functionally significant domain. Using the yeast two-hybrid assay and an in vitro biochemical assay, it is here shown that a protein, B112, interacts specifically with the carboxy-terminal segment of human BRCA1 from residue 1602 to 1863. A germ line truncation mutation, 1853ter, that removes the last 11 amino acids from the carboxy-terminus of BRCA1 abolishes not only the transcription activation function, but also binding to B112. The B112 protein is apparently the same as an uncharacterized protein known as CtIP, the sequence of which was previously deposited in GenBank. Screenings of a panel of 92 tumor cell lines for mutations in the B112/CtIP sequence have identified a number of missense variants, including a non-conserved lysine to glutamic acid change at codon 337 in the pancreatic cancer line, BxPC3. Taken together, these results indicate that B112/CtIP participates in a common biochemical pathway as BRCA1 and that the interaction of these two proteins may be required for the tumor suppressor function of BRCA1.

Recent evidence indicates that the carboxy-terminal region of the tumor suppressor protein BRCA1 is a functionally significant domain. Using the yeast two-hybrid assay and an in vitro biochemical assay, it is here shown that a protein, B112, interacts specifically with the carboxy-terminal segment of human BRCA1 from residue 1602 to 1863. A germ line truncation mutation, 1853ter, that removes the last 11 amino acids from the carboxy-terminus of BRCA1 abolishes not only the transcription activation function, but also binding to B112. The B112 protein is apparently the same as an uncharacterized protein known as CtIP, the sequence of which was previously deposited in GenBank. Screenings of a panel of 92 tumor cell lines for mutations in the B112/CtIP sequence have identified a number of missense variants, including a non-conserved lysine to glutamic acid change at codon 337 in the pancreatic cancer line, BxPC3. Taken together, these results indicate that B112/CtIP participates in a common biochemical pathway as BRCA1 and that the interaction of these two proteins may be required for the tumor suppressor function of BRCA1.