X chromosomal regulation in flies: when less is more

In Drosophila, dosage compensation of the single male X chromosome involves upregulation of expression of X linked genes. Dosage compensation complex or the male specific lethal (MSL) complex is intimately involved in this regulation. The MSL complex members decorate the male X chromosome by binding on hundreds of sites along the X chromosome. Recent genome wide analysis has brought new light into X chromosomal regulation. It is becoming increasingly clear that although the X chromosome achieves male specific regulation via the MSL complex members, a number of general factors also impinge on this regulation. Future studies integrating these aspects promise to shed more light into this epigenetic phenomenon.     

Susceptibility genes in breast cancer: more is less?

PALB2, which encodes a BRCA2-interacting protein, is a breast cancer susceptibility gene
Rahman et al. (2007)
Nature Genetics 39: 165–167
A common coding variant in CASP8 is associated with breast cancer risk
Cox et al. (2007)
Nature Genetics 39: 352–358
A genome-wide association study identifies alleles in FGFR2 associated with risk of sporadic postmenopausal breast cancer
Hunter et al. (2007)
Nature Genetics 39: 870–874
Genome-wide association study identifies novel breast cancer susceptibility loci
Easton et al. (2007)
Nature 447: 1087–1093
Common variants on chromosomes 2q35 and 16q12 confer susceptibility to estrogen receptor–positive breast cancer
Stacey et al. (2007)
Nature Genetics 39: 865–869     

Interstitial deletion 5q14.3q21.3 with MEF2C haploinsufficiency and mild phenotype: when more is less

An 18-year-old female with mild mental disability (global IQ 69), febrile seizures with subsequent myoclonic/grand mal epilepsy, and subtle morphologic changes is described with del 5(q14.3q21.3) by karyotype and minimal DNA deletion of 21.08 Mb by array comparative genomic hybridization microarray analysis (arr chr5:83,592,798-104,671,993 X1) that encompasses at least 50 genes. Included in the deletion interval is the MEF2C gene that usually causes severe mental disability when haploinsufficient, illustrating the complexity of clinic-cytogenetic correlation even with defined segmental aneuploidy. Interaction of MEF2C with the deleted febrile seizure (FEB4) and juveline myoclonic epilepsy (EJM4) loci plus the G-protein receptor (GPR98/MASS1/Usher syndrome) gene may moderate the phenotype, perhaps through common regulation by calcium.     

Circulating tumor cells: getting more from less

Recent insights into circulating tumor cells (CTCs) have been driven by numerous technological innovations aimed at isolating, purifying, and analyzing these rare cells. However, the information density within these cells has yet to be truly accessed and exploited for patient benefit. A device reported by Issadore et al. in this issue of Science Translational Medicine proposes a highly sensitive methodology that may both extend CTC capture to a broader patient population and provide greater understanding of biological targets for personalized medical therapies.