BRCA1 and BRCA2 are important for DNA double-strand break repair by homologous recombination, and mutations in these genes predispose to breast and other cancers. Poly(ADP-ribose) polymerase (PARP) is an enzyme involved in base excision repair, a key pathway in the repair of DNA single-strand breaks. We show here that BRCA1 or BRCA2 dysfunction unexpectedly and profoundly sensitizes cells to the inhibition of PARP enzymatic activity, resulting in chromosomal instability, cell cycle arrest and subsequent apoptosis. This seems to be because the inhibition of PARP leads to the persistence of DNA lesions normally repaired by homologous recombination. These results illustrate how different pathways cooperate to repair damage, and suggest that the targeted inhibition of particular DNA repair pathways may allow the design of specific and less toxic therapies for cancer.

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Inactivation of p53 contributes significantly to the dismal prognosis of breast tumors, most notably triple-negative breast cancers (TNBCs). How the relief from p53 tumor suppressive functions results in tumor cell aggressive behavior is only partially elucidated. In an attempt to shed light on the implication of microRNAs in this context, we discovered a new signaling axis involving p53, miR-30a and ZEB2. By an in silico approach we identified miR-30a as a putative p53 target and observed that in breast tumors reduced miR-30a expression correlated with p53 inactivation, lymph node positivity and poor prognosis. We demonstrate that p53 binds the MIR30A promoter and induces the transcription of both miRNA strands 5p and 3p. Both miR-30a-5p and -3p showed the capacity of targeting ZEB2, a transcription factor involved in epithelial–mesenchymal transition (EMT), tumor cell migration and drug resistance. Intriguingly, we found that p53 does restrain ZEB2 expression via miR-30a. Finally, we provide evidence that the new p53/miR-30a/ZEB2 axis controls tumor cell invasion and distal spreading and impinges upon miR-200c expression. Overall, this study highlights the existence of a novel axis linking p53 to EMT via miR-30a, and adds support to the notion that miRNAs represent key elements of the complex network whereby p53 inactivation affects TNBC clinical behavior.

This is the first prospective randomized study of ASI in a large population of patients with renal carcinoma after radical nephrectomy. Our data clearly indicate that ASI can increase the reactivity to autologous tumor, as measured by the DTCH test, but it appears unable to affect DFS and OS of patients.

Increasing evidence indicates that invasive properties of breast cancers rely on gain of mesenchymal and stem features, which has suggested that the dual targeting of these phenotypes may represent an appealing therapeutic strategy. It is known that the fraction of stem cells can be enriched by culturing breast cancer cells as mammospheres (MS), but whether these pro-stem conditions favor also the expansion of cells provided of mesenchymal features is still undefined. In the attempt to shed light on this issue, we compared the phenotypes of a panel of 10 breast cancer cell lines representative of distinct subtypes (luminal, HER2-positive, basal-like and claudin-low), grown in adherent conditions and as mammospheres. Under MS-proficient conditions, the increment in the fraction of stem-like cells was associated to upregulation of the mesenchymal marker Vimentin and downregulation of the epithelial markers expressed by luminal cells (E-cadherin, KRT18, KRT19, ESR1). Luminal cells tended also to upregulate the myoepithelial marker CD10. Taken together, our data indicate that MS-proficient conditions do favor mesenchymal/myoepithelial features, and indicate that the use of mammospheres as an in vitro tumor model may efficiently allow the exploitation of therapeutic approaches aimed at targeting aggressive tumors that have undergone epithelial-to-mesenchymal transition.

The heritable defects of BRCA1 and BRCA2 genes have been shown to predispose to breast and ovarian cancers. In a previous report, we analyzed 46 Italian families with breast and/or ovarian cancer for BRCA1 mutations. In the present study, those families and 11 others were screened for BRCA2 mutations; the newly enrolled families were also analyzed for the BRCA1 gene. The coding region and splice boundaries of BRCA2 and BRCA1 genes were assessed by the protein‐truncation test and single‐strand conformational polymorphism. A total of 20 different mutations were found in 21 families (37%). A total of 9 families (16%) showed mutations in the BRCA1 gene, including the one new mutation identified in this study (5382insC), and 12 families (21%) presented mutations in the BRCA2 gene. BRCA2‐mutated families presented breast and ovarian cancers or breast cancers only, whereas most BRCA1‐mutated families presented ovarian cancer alone or in association with breast cancer. All the BRCA2 mutations led to a truncated protein: 6 were frameshift mutations, 4 were non‐sense mutations and 2 involved the intronic invariant region leading to splice variants. Therefore, in the Italian population, the cumulative proportion of BRCA1 and BRCA2 mutations was within the range observed in other studies (37%), with higher involvement of BRCA2 than of BRCA1. Many families in which no mutations were found presented a very high incidence of breast and/or ovarian cancer. Among the 36 BRCA1 and BRCA2 wild‐type families, 24 presented at least 4 cancer cases, indicating the existence of other important predisposing genes. Int. J. Cancer 83:5–9, 1999. © 1999 Wiley‐Liss, Inc.

Deleterious mutations of the BRCA1 and BRCA2 genes are a major risk factor for the development of breast and ovarian cancers. [1][2][3][4] Mutation tests for these two genes commonly are now offered in specialised clinics.5 6 As a result, a large number of women with personal or family histories of breast or ovarian cancer seek genetic counselling. Accurate evaluation of the probability that a woman carries a germline pathogenic mutation at BRCA1 or BRCA2 therefore is essential to help counsellors and those being counselled to decide whether testing is appropriate. In this context, the questions of practical interest are: Given the pedigree, what is the chance of a mutation being present? and What is the chance of the DNA laboratory finding a mutation?After testing became available, several models were developed to assess the pre-test probability of identifying carriers of mutations. Broadly speaking, two different approaches have been used to develop predictive models: the ''empirical approach'' and the ''Mendelian approach''.7 In empirical models, families are stratified according to variables that describe their family history; regression or other approaches are used to predict the results of Mendelian testing. In some cases, this approach simply consists of observing the proportion of mutations found in different strata. Mendelian models, in contrast, address the probability that a proband is a mutation carrier on the basis of explicit assumptions about the genetic parameters (allele frequencies and cancer penetrances in carriers and non-carriers) and the Mendelian rules of gene transmission. A consequence of the two different strategies is that the Mendelian models evaluate the probability that a proband is a gene carrier, whereas the empirical models evaluate the probability of identifying a mutation.The main purpose of this study was to compare the performances of published models in predicting mutation test results in a large dataset. We collected pedigrees of probands investigated for BRCA1 and BRCA2 mutations in five clinical centres included in the Italian Consortium for Hereditary Breast and Ovarian Cancer. The combined sample included 568 families. Among those, 80 pathogenic mutations were identified in the BRCA1 gene and 53 in the BRCA2 gene. Eight models were investigated: the University of Pennsylvania (Penn) model, the Myriad-1 model, the Myriad Tables, the Spanish model, the Finnish model, the Yale model, the Brcapro model, [8][9][10][11][12][13][14][15][16][17] and a novel model that we refer to as the Italian Consortium (IC) model, intended to be used as a research tool. The latter is based on the parameter values of Brcapro (with minor modifications) and is implemented in the Mlink program of the Fastlink package. 18Mutations of the two genes are associated with differences in familial presentations. BRCA1 is mutated preferentially in families with breast and ovarian cancer and more rarely is mutated in families with male breast cancer.19-21 BRCA2 was mapped primarily through families with m...