Purpose Cisplatin is a chemotherapeutic agent not used routinely for breast cancer treatment. As a DNA cross-linking agent, cisplatin may be effective treatment for hereditary BRCA1-mutated breast cancers. Because sporadic triple-negative breast cancer (TNBC) and BRCA1-associated breast cancer share features suggesting common pathogenesis, we conducted a neoadjuvant trial of cisplatin in TNBC and explored specific biomarkers to identify predictors of response. Patients and Methods Twenty-eight women with stage II or III breast cancers lacking estrogen and progesterone receptors and HER2/Neu (TNBC) were enrolled and treated with four cycles of cisplatin at 75 mg/m2 every 21 days. After definitive surgery, patients received standard adjuvant chemotherapy and radiation therapy per their treating physicians. Clinical and pathologic treatment response were assessed, and pretreatment tumor samples were evaluated for selected biomarkers. Results Six (22%) of 28 patients achieved pathologic complete responses, including both patients with BRCA1 germline mutations;18 (64%) patients had a clinical complete or partial response. Fourteen (50%) patients showed good pathologic responses (Miller-Payne score of 3, 4, or 5), 10 had minor responses (Miller-Payne score of 1 or 2), and four (14%) progressed. All TNBCs clustered with reference basal-like tumors by hierarchical clustering. Factors associated with good cisplatin response include young age (P = .001), low BRCA1 mRNA expression (P = .03), BRCA1 promoter methylation (P = .04), p53 nonsense or frameshift mutations (P = .01), and a gene expression signature of E2F3 activation (P = .03). Conclusion Single-agent cisplatin induced response in a subset of patients with TNBC. Decreased BRCA1 expression may identify subsets of TNBCs that are cisplatin sensitive. Other biomarkers show promise in predicting cisplatin response.

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Pheochromocytomas are catecholamine-secreting tumors that result from mutations of at least six different genes as components of distinct autosomal dominant disorders. However, there remain familial occurrences of pheochromocytoma without a known genetic defect. We describe here a familial pheochromocytoma syndrome consistent with digenic inheritance identified through a combination of global genomics strategies. Multipoint parametric linkage analysis revealed identical LOD scores of 2.97 for chromosome 2cen and 16p13 loci. A two-locus parametric linkage analysis produced maximum LOD score of 5.16 under a double recessive multiplicative model, suggesting that both loci are required to develop the disease. Allele-specific loss of heterozygosity (LOH) was detected only at the chromosome 2 locus in all tumors from this family, consistent with a tumor suppressor gene. Four additional pheochromocytomas with a similar genetic pattern were identified through transcription profiling and helped refine the chromosome 2 locus. High-density LOH mapping with single nucleotide polymorphism-based array identified a total of 18 of 62 pheochromocytomas with LOH within the chromosome 2 region, which further narrowed down the locus to <2 cM. This finding provides evidence for two novel susceptibility loci for pheochromocytoma and adds a recessive digenic trait to the increasingly broad genetic heterogeneity of these tumors. Similarly, complex traits may also be involved in other familial cancer syndromes. (Cancer Res 2005; 65(21): 9651-8)

Seasonal Response of the Equatorial time so there must be a divergence of heat from Atlantic/Programme Fran9ais Ocean et Climat dans these regions. In the interior of the Gulf of l'Atlantique Equatorial data for 1984 are analyzed Guinea the surface heat flux is out of the ocean. to estimate heat fluxes in the interior of the Gulf of Guinea between IøN and 4øN. In this region during May-July the mixed layer, roughly 35 m deep, cools uniformly by nearly 4øC in 3 months representing • mean rate of heat loss of approximately 70 W/m-. Climatic heat budget calculations by Hastenrath and L•mb (1978) show a surface flux heat loss of 30 W/m-during this time. This suggests that although surface flux makes a significant contribution to the mixed layer cooling, additional divergent heat flux is required to balance the local heat budget. All advective and diffusive terms are estimated to be small except for the meridional eddy heat flux v'T'. The cospectrum of v and T has a peak near 15 days. At this frequency, v is coherent with the meridional wind. The thermocline displacements forced by this meridiona! wind are nearly antisymmetric about the equator. The frequency, meridional length scale, and asymmetry of these fluctuations suggest that a second baroclinic Rossby-gravity wave is being locally forced. Thus in the interior of the Gulf of Guinea the eddy flux driven by the fortnightly wind fluctuations makes a significant contribution to the cooling of the mixed layer during the seasonal upwelling. This is in contrast to the central and western equatorial Atlantic Ocean, where a meridional heat flux is produced by 25 to 30 day fluctuations generated by current instabilities.

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Pancreatic amyloid plaques formed by the pancreatic islet amyloid polypeptide (IAPP) are present in more than 95% of type II diabetes mellitus patients, and their abundance correlates with the severity of the disease. IAPP is currently considered the most amyloidogenic peptide known, but the molecular bases of its aggregation are still incompletely understood. Detailed characterization of the mechanisms of amyloid formation requires large quantities of pure material. Thus, availability of recombinant IAPP in sufficient amounts for such studies constitutes an important step toward elucidation of the mechanisms of amyloidogenicity. Here, we report, for the first time, the successful expression, purification and characterization of the amyloidogenicity and cytotoxicity of recombinant human mature IAPP. This approach is likely to be useful for the production of other amyloidogenic peptides or proteins that are difficult to obtain by chemical synthesis.

Dicer is central to the RNA interference (RNAi) pathway, because it is required for processing of double-stranded RNA (dsRNA) precursors into small RNA effector molecules. In principle, any long dsRNA could serve as a substrate for Dicer. The X inactive specific transcript (Xist) is an untranslated RNA that is required for dosage compensation in mammals. It coats and silences 1 of the 2 X chromosomes in female cells and initiates a chromosomewide change in chromatin structure that includes the recruitment of Polycomb proteins, but it is largely unknown how Xist RNA mediates these processes. To investigate a potential link between the RNAi pathway and X inactivation, we generated and analyzed Dicer-deficient embryonic stem (ES) cells. In the absence of Dicer, coating by Xist RNA, initiation of silencing, and recruitment of Polycomb proteins occur normally. Dicer ablation had modest effects on the steady-state levels of spliced Xist RNA. Together our data indicate that the RNAi machinery is not essential for the initiation of X inactivation.icer is an RNase III-like enzyme involved in the generation of small double-stranded RNAs (dsRNA) from long doublestranded precursors (1, 2). Dicer cleavage products, which are classified as microRNAs (miRNAs) and endogenous small interfering RNAs (esiRNAs), are then bound by Argonautes (Ago) within multiprotein complexes and can regulate gene expression via several distinct mechanisms (3, 4). miRNAs have been extensively characterized (5), and the majority of miRNAs mediate posttranscriptional gene silencing (PTGS) by inhibiting translation of cognate mRNAs and/or promoting mRNA decay (6, 7). esiRNAS can be generated by transcription of sense and antisense transcripts, which can then form dsRNA and get processed by Dicer. The characterization of esiRNAs is currently less advanced (8). They have been cloned from the germ line of mammalian organisms (9-11), and their existence in somatic cells is anticipated (12) because any long double-stranded RNA in a cell could, in principle, be processed by Dicer.One process that involves long, untranslated RNAs is the silencing of the X chromosome in female mammalian cells. The X inactive specific transcript (Xist), is a nuclear RNA transcribed from the inactive X chromosome (Xi). In female mammals, Xist RNA is absolutely required for dosage compensation, which is initiated during early embryogenesis (13-15). Upon counting of the X chromosomes, 1 X is designated to remain active (Xa), and Xist is transcriptionally up-regulated on the other X, which is destined to be inactivated. The Xist RNA accumulates on this chromosome in cis and mediates transcriptional gene silencing through unknown mechanisms. Polycomb group (PcG) proteins are recruited to the Xist RNA-associated chromosome and establish chromosomewide histone modifications that include histone H3 lysine 27 trimethylation (16,17). Later in the process, additional chromatin marks, ranging from H3K9 and H4K20 methylation to DNA methylation and histone variant recruitment, become enrich...