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Background:Population-based studies of breast cancer have estimated that at least some PALB2 mutations are associated with high breast cancer risk. For women carrying PALB2 mutations, knowing their carrier status could be useful in directing them towards effective cancer risk management and therapeutic strategies. We sought to determine whether morphological features of breast tumours can predict PALB2 germline mutation status.Methods:Systematic pathology review was conducted on breast tumours from 28 female carriers of PALB2 mutations (non-carriers of other known high-risk mutations, recruited through various resources with varying ascertainment) and on breast tumours from a population-based sample of 828 Australian women diagnosed before the age of 60 years (which included 40 BRCA1 and 18 BRCA2 mutation carriers). Tumour morphological features of the 28 PALB2 mutation carriers were compared with those of 770 women without high-risk mutations.Results:Tumours arising in PALB2 mutation carriers were associated with minimal sclerosis (odds ratio (OR)=19.7; 95% confidence interval (CI)=6.0-64.6; P=5 × 10−7). Minimal sclerosis was also a feature that distinguished PALB2 mutation carriers from BRCA1 (P=0.05) and BRCA2 (P=0.04) mutation carriers.Conclusion:This study identified minimal sclerosis to be a predictor of germline PALB2 mutation status. Morphological review can therefore facilitate the identification of women most likely to carry mutations in PALB2. [ABSTRACT FROM AUTHOR]

Presents a letter to the editor which reports that X-linked inhibitors of apoptosis protein-deficiency leads to delayed lobuloalveolar development in the mammary gland.

Presents a letter to the editor about novel p53 germline mutation in a patient with Li-Fraumeni syndrome.

The article reviews the known characteristics of mammary stem and progenitor cells by considering the hierarchy of epithelial cell types in the mammary gland of a mouse model. It attempts to provide insight into the cells of origin in the different subtypes of breast cancer as well as the nature of cancer-propagating cells. Also discussed are the steroid receptor status of mammary stem and progenitor cells and the pathways that have been implicated in regulating their self-renewal and differentiation

Background: Few data exist regarding the use of complementary and alternative medicine (CAM) by unaffected women at high risk of breast cancer., Methods: Self-reported CAM use by women from multiple-case breast cancer families was obtained by questionnaire. Factors associated with CAM use were assessed using multiple logistic regression., Results: Of 892 women, 55% (n=489) used CAM, 6% (n=53) specifically to prevent cancer. CAM use was independently associated with tertiary education level (OR 2.56, 95% CI 1.83-3.58, p<0.001), greater physical activity (OR 1.05 per hour of physical activity/week, 95% CI 1.00-1.10, p=0.049), greater anxiety (OR 1.92, 95% CI 1.16-3.16, p=0.01), not currently smoking (OR 0.64, 95% CI 0.42-0.97, p=0.037) and lower perceived BC risk (OR 0.82 per 20 percentage points, 95% CI 0.72-0.94, p=0.005)., Conclusions: The majority of high-risk women use CAM, but mostly for reasons other than cancer prevention. Most predictors of CAM use are consistent with the limited literature for women at high risk for cancer.

LMO4 belongs to a family of LIM-only transcriptional regulators, the first two members of which are oncoproteins in acute T cell leukemia. We have explored a role for LMO4, initially described as a human breast tumor autoantigen, in developing mammary epithelium and breast oncogenesis. Lmo4 was expressed predominantly in the lobuloalveoli of the mammary gland during pregnancy. Consistent with a role in proliferation, forced expression of this gene inhibited differentiation of mammary epithelial cells. Overexpression of LMO4 mRNA was observed in 5 of 10 human breast cancer cell lines. Moreover, in situ hybridization analysis of 177 primary invasive breast carcinomas revealed overexpression of LMO4 in 56% of specimens. Immunohistochemistry confirmed overexpression in a high percentage (62%) of tumors. These studies imply a role for LMO4 in maintaining proliferation of mammary epithelium and suggest that deregulation of this gene may contribute to breast tumorigenesis.

The nuclear LIM-only (LMO) transcription factors LMO2 and LMO4 play important roles in both normal and leukemic T-cell development. LIM domains are cysteine/histidine-rich domains that contain two structural zinc ions and that function as protein-protein adaptors; members of the LMO family each contain two closely spaced LIM domains. These LMO proteins all bind with high affinity to the nuclear protein LIM domain binding protein 1 (ldb1). The LMO-ldb1 interaction is mediated through the N-terminal LIM domain (LIM1) of LMO proteins and a 38-residue region towards the C-terminus of ldb1 [ldb1(LID)]. Unfortunately, recombinant forms of LMO2 and LMO4 have limited solubility and stability, effectively preventing structural analysis. Therefore, we have designed and constructed a fusion protein in which ldb1(LID) and LIM1 of LMO2 can form an intramolecular complex. The engineered protein, FLIN2 (fusion of the LIM interacting domain of ldb1 and the N-terminal LIM domain of LMO2) has been expressed and purified in milligram quantities. FLIN2 is monomeric, contains significant levels of secondary structure and yields a sharp and well-dispersed one-dimensional (1)H NMR spectrum. The analogous LMO4 protein, FLIN4, has almost identical properties. These data suggest that we will be able to obtain high-resolution structural information about the LMO-ldb1 interactions.

E2F is a family of transcription factors required for normal cell cycle control and for cell cycle arrest in G1. E2F4 is the most abundant E2F protein in many cell types. In quiescent cells, it is localized to the nucleus, where it is bound to the retinoblastoma-related protein p130. During entry into the cell cycle, the protein disappears from the nucleus and appears in the cytoplasm. The mechanism by which this change occurs has, in the past, been unclear. We have found that E2F4 is actively exported from the nucleus and that leptomycin B, a specific inhibitor of nuclear export, inhibits this process. E2F4 export is mediated by two hydrophobic export sequences, mutations in either of which result in export failure. Individual export mutants of E2F4, but not a mutant with inactivation of both export signals, can be efficiently excluded from the nucleus by forced coexpression of the nuclear export receptor CRM1. Similarly, CRM1 overexpression can prevent cell cycle arrest induced by the cyclin kinase inhibitor p16(INK4a), an E2F4-dependent process. Taken together, these data suggest that nuclear export contributes to the regulation of E2F4 function, including its ability to regulate exit from G1 in association with a suitable pocket protein.

E2F transcription factors are major regulators of cell proliferation. The diversity of the E2F family suggests that individual members perform distinct functions in cell cycle control. E2F4 and E2F5 constitute a defined subset of the family. Until now, there has been little understanding of their individual biochemical and biological functions. Here, we report that simultaneous inactivation of E2F4 and E2F5 in mice results in neonatal lethality, suggesting that they perform overlapping functions during mouse development. Embryonic fibroblasts isolated from these mice proliferated normally and reentered from Go with normal kinetics compared to wild-type cells. However, they failed to arrest in G1 in response to p16INK4a. Thus, E2F4 and E2F5 are dispensable for cell cycle progression but necessary for pocket protein-mediated G1 arrest of cycling cells.

Proapoptotic Bcl-2 family members activate cell death by neutralizing their anti-apoptotic relatives, which in turn maintain cell viability by regulating the activation of the cell death effectors, the caspases. Bim belongs to a distinct subgroup of proapoptotic proteins that only resemble other Bcl-2 family members within the short BH3 domain. Gene targeting experiments in mice have shown that Bim is essential for the execution of some but not all apoptotic stimuli, for hematopoietic cell homeostasis, and as a barrier against autoimmunity. There are three Bim isoforms, Bim(S), Bim(L), and Bim(EL), which have different proapoptotic potencies due at least in part to differences in interaction with the dynein motor complex. The expression pattern of Bim was investigated by immunohistochemical staining, immunoprecipitation followed by Western blotting, and in situ hybridization. Bim was found in hematopoietic, epithelial, neuronal, and germ cells. Bim(L) and Bim(EL) were coexpressed at similar levels in many cell types, but Bim(S) was not detected. Microscopic examination revealed a punctate pattern of Bim(L) and Bim(EL) immunostaining, indicating association with cytoplasmic structures. These results are discussed in the context of the phenotype of Bim-deficient mice and the post-translational regulation of Bim's pro-apoptotic activity.

The E2F family of transcription factors plays a crucial role in cell cycle progression. E2F activity is tightly regulated by a number of mechanisms, which include the timely synthesis and degradation of E2F, interaction with retinoblastoma protein family members ("pocket proteins"), association with DP heterodimeric partner proteins, and phosphorylation of the E2F/DP complex. Here we report that another mechanism, subcellular localization, is important for the regulation of E2F activity. Unlike E2F-1, -2, or -3, which are constitutively nuclear, ectopic E2F-4 and -5 were predominantly cytoplasmic. Cotransfection of expression vectors encoding p107, p130, or DP-2, but not DP-1, resulted in the nuclear localization of E2F-4 and -5. Moreover, the transcriptional activity of E2F-4 was markedly enhanced when it was invariably nuclear. Conversely, it was reduced when the protein was excluded from the nucleus, implying that E2F-4 transcription function depends upon its cytological location. In keeping with this, the nuclear/cytoplasmic ratios of endogenous E2F-4 changed as cells exited G0, with high ratios in G0 and early G1 and a progressive increase in cytoplasmic E2F-4 as cells approached S phase. Thus, the subcellular location of E2F-4 is regulated in a cell cycle-dependent manner, providing another potential mechanism for its functional regulation.

An unusual mouse line (max 41) that carries an inserted transgene encoding the nuclear transcription factor, Max, exhibits a 50- to 60-fold elevation of blood neutrophils and a 10-fold elevation of blood monocytes. Analysis showed that these elevated levels of blood cells were sustained incrementally by a sevenfold increase in mature neutrophils in the bone marrow and spleen and a fourfold increase in granulocyte-committed progenitor cells with normal turnover times for mature neutrophils and monocytes in the marrow and blood. the progenitor cells were not autonomous and exhibited a normal quantitative responsiveness to stimulation in vitro by the four colony-stimulating factors. A consistent anomaly noted was that, when stimulated by macrophage colon-stimulating factor, max 41 progenitor cells formed mainly granulocyte-containing colonies, rather than the usual macrophage colonies. The blast colony-forming cells from max 41 mice did not generate abnormal numbers or types of progenitor cells. The transgenic max 41 model requires further analysis to establish the regulatory anomaly responsible for the excessive production of granulocytes and monocytes, but has emphasized that most neutrophils generated in the marrow normally never leave the organ.

The cellular growth promoting function of the Myc oncoprotein requires its heterodimerization with the Max protein, but Max can also form complexes that inhibit Myc action. To determine whether max overexpression in vivo is oncogenic and whether it can modulate the action of Myc, we generated transgenic mice in which the max gene was directed to express in lymphoid cells by a linked immunoglobulin heavy chain enhancer (E mu). Expression of the transgene at substantially higher levels than the endogenous max gene did not perturb lymphoid homeostasis in adult animals nor predispose to lymphomagenesis. The numbers of B-lymphoid cells in very young animals were reduced. Moreover, analysis of bi-transgenic E mu-myc/E mu-max mice revealed that max overexpression attenuated the premalignant B-lymphoproliferative state induced by an E mu-myc transgene and reduced the rate of lymphoma onset. These results suggest that elevation of Max expression in vivo inhibits the function of Myc.

B-lymphoid and myeloid development are markedly perturbed in a unique transgenic mouse strain, max 41. Pro-B, pre-B, and B lymphocytes were severely reduced but granulocytes were greatly elevated. This phenotype could be adoptively transferred with bone marrow cells. It was not alleviated by bcl-2 or myc transgenes that promote lymphocyte survival or proliferation. Bitransgenic myc/max 41 mice developed pre-B cell lymphoma. An accompanying massive granulocytosis unexpectedly proved to be clonally derived from the pre-B lymphoma cells. These observations suggest that B lymphopoiesis in max 41 mice has been diverted to granulocyte production. Since neither cell type expressed the transgene, this novel lymphomyeloid deviation probably reflects insertional alteration of a hematopoietic regulatory gene.

Cyclin D1 is the regulatory subunit of certain protein kinases thought to advance the G1 phase of the cell cycle. Deregulated cyclin D1 expression has been implicated in several human neoplasms, most consistently in centrocytic B lymphoma, where the cyclin D1 gene usually has been translocated to an immunoglobulin locus. To determine directly whether constitutive cyclin D1 expression is lymphomagenic, transgenic mice were generated having the cyclin D1 gene linked to an immunoglobulin enhancer. Despite abundant transgene expression, their lymphocytes were normal in cell cycle activity, size and mitogen responsiveness, but young transgenic animals contained fewer mature B- and T-cells. Although spontaneous tumours were infrequent, lymphomagenesis was much more rapid in mice that co-expressed the cyclin D1 transgene and a myc transgene than in mice expressing either transgene alone. Moreover, the spontaneous lymphomas of myc transgenic animals often ectopically expressed the endogenous cyclin D1 gene. These findings indicate that this G1 cyclin can modulate differentiation and collaborate with myc-like genes in oncogenesis.

To assess the optimal duration and method of administration of adjuvant cyclophosphamide, methotrexate and 5-fluorouracil (CMF) chemotherapy, 116 patients with positive axillary nodes after total mastectomy and axillary dissection were reviewed retrospectively. CMF was administered in three progressively shorter regimens, which consisted of oral CMF for either 12 or six cycles and intravenous (i.v.) CMF for six cycles. Median follow-up for surviving patients was 62 months. The three groups were matched for major prognostic factors. There was no advantage in using more than six cycles of adjuvant CMF. There was an improved crude 3 year disease-free survival (84 vs 65%, P = 0.05) and a trend towards improved overall survival (92 vs 85%, P = NS) in patients treated with six cycles of oral CMF compared with i.v. CMF. Survival rates were not significantly different beyond 3 years. Leucopenia and alopecia were more severe with oral CMF (P less than 0.01), and compliance worse with oral CMF x 12 (P = 0.01). Since the data suggest that i.v. CMF is at least as equal as oral CMF a randomized controlled trial should be undertaken.

Testicular seminoma comprises fewer than 1% of male cancers but is a relatively common malignancy in young men. The management and outcome of 73 consecutive patients with testicular seminoma were reviewed. Median follow-up was 51 months (range: 15-109 months). Their median age was 37 years (range: 21-67 years). There was a history of testicular maldescent in 5.5% of patients. Beta-human chorionic gonadotropin was elevated in 22% of patients prior to orchidectomy and in 5% post-surgery. The majority of patients had stage I (78%) or stage II (19%) seminoma after clinical staging. One patient (2%) with stage I seminoma relapsed, while two patients (14%) with stage II seminoma relapsed. The latter two were salvaged with further therapy. One of two patients treated for stage III seminoma died. A residual mass after radiotherapy was commonly observed in patients with stage II seminoma, but did not represent viable tumour. These results reflect the high cure rates that are achievable in seminoma with radiotherapy for early stage and non-bulky abdominal disease and, more recently, with cisplatin-based chemotherapy for bulky abdominal or disseminated disease.

Determining the extent of intra-abdominal spread of testicular seminoma by radiographic studies is an essential step in planning rational treatment following orchidectomy. CT scanning is generally accepted as being superior to lymphangiography in assessing the retroperitoneal space. We reviewed the relative contribution of these two procedures in a retrospective analysis of 73 consecutive patients with testicular seminoma managed at Westmead Hospital between January 1980 and September 1987. Abdominal CT scans and bipedal lymphangiography (LAG) were carried out in 72 and 51 patients respectively, 50 patients undergoing both procedures. We found concordance between the two techniques to be 88%. Upstaging occurred in 5 patients using CT (10%), 7 patients using LAG (14%), and in 8 patients (16%) when both tests were utilised. Four patients were upstaged by both techniques while the remaining 4 patients were upstaged using one technique alone. Serum beta-HCG was not a reliable screen for residual disease. Residual disease in the few patients with an elevated serum beta-HCG was easily detected by CT scanning. We conclude that there is a continuing role for LAG in assessing patients with clinical Stage I seminoma when the abdominal CT scan is equivocal or normal.