Marfan syndrome results from mutations in an extracellular matrix glycoprotein, fibrillin. Previous studies have characterized approximately 6.9-kb of the estimated 10-kb fibrillin transcript. We have now completed the primary structure of fibrillin, elucidated the exon/intron organization of the gene and derived a physical map of the genetic locus. Pre-fibrillin consists of 2,871 amino acids which, excluding the signal peptide, are arranged into five structurally distinct regions. The largest of these regions comprises about 75% of the entire protein and consists of numerous repeated cysteine-rich sequences homologous to the peptide motifs of the epidermal growth factor (EGF) and transforming growth factor-beta binding protein (TGF-bp). Forty-three of the forty-six EGF-like repeats contain a calcium binding consensus sequence (EGF-CB) conceivably mediating protein-protein interactions. Fibrillin exhibits a few additional cysteine-rich modules that are apparently unique to this macromolecule and may represent evolutionary variants of the EGF-CB and TGF-bp motifs. Almost all of the cysteine-rich repeats are encoded by single exons; consequently, the fibrillin gene is relatively large (approximately 110-kb) and highly fragmented (65 exons). This study provides the first comprehensive analysis of the fibrillin gene and relevant information for the full characterization of Marfan syndrome mutations.

Purpose: Endoxifen is the major mediator of tamoxifen effect and endoxifen levels <15 nmol/L may be associated with increased risk of breast cancer recurrence. We increased tamoxifen dose in breast cancer patients with low endoxifen levels and assessed the influence of various parameters on reaching 15 nmol/L and 30 nmol/L endoxifen levels.Experimental Design: Tamoxifen dose was increased in those with endoxifen levels below 30 nmol/L. Toxicity, including hot flash score, was measured. CYP2D6 metabolizer status was classified as ultra-rapid (UM), extensive (EM), intermediate (IM), or poor (PM) based genotype of somatic DNA.Results: Dosage was escalated in 68 of 122 participants. On 20 mg tamoxifen, 24% had endoxifen levels below 15 nmol/L and this reduced to 6% following dose escalation. In over 50% of cases, there was no identified cause for low endoxifen. Low baseline endoxifen level, and not CYP2D6 metabolizer status, independently predicted reaching threshold targets for both the 15 nmol/L and 30 nmol/L targets (P ¼ 0.04 and 0.003 respectively). The 15 nmol/L target was reached in all UM/EM and IM patients, 63% of PM patients, and 58% of those with baseline endoxifen of <10 nmol/L. There was no correlation between hot flash score and genotype or any tamoxifen metabolite level including endoxifen (R ¼ 0.07).Conclusions: Low endoxifen on standard dose tamoxifen was the only independent predictor of failure to achieve potentially therapeutic levels. Trials examining tamoxifen dose escalation and breast cancer outcome should be guided by endoxifen levels alone, without reference to CYP2D6 genotype or presence of hot flashes.

Genetic linkage between atopic IgE responses and chromosome 11q13 (DI1S97) has been previously reported in a limited number of extended families. Difficulties of phenotyping in the older family members, poor family structure in some families, and genetic heterogeneity were proposed as possible explanations for the variability in lod scores. To test this finding a second linkage study of 64 young nuclear families was undertaken and gave a two point lod score of 3-8 at 0 = 0 07 (assuming Om = Of). A test of genetic heterogeneity in the nuclear families shows that atopic IgE responses are linked to this locus in 60 to 100% of families (approximate 95% confidence limits).

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These data demonstrate that voreloxin is a broadly active anti-tumor agent in vitro and in vivo, with potent activity in aggressive and drug-resistant tumor models.