Microcephaly and medulloblastoma may both result from mutations that compromise genomic stability. We report that ATR, which is mutated in the microcephalic disorder Seckel syndrome, sustains cerebellar growth by maintaining chromosomal integrity during postnatal neurogenesis. Atr deletion in cerebellar granule neuron progenitors (CGNPs) induced proliferation-associated DNA damage, p53 activation, apoptosis and cerebellar hypoplasia in mice. Co-deletions of either p53 or Bax and Bak prevented apoptosis in Atr-deleted CGNPs, but failed to fully rescue cerebellar growth. ATR-deficient CGNPs had impaired cell cycle checkpoint function and continued to proliferate, accumulating chromosomal abnormalities. RNA-Seq demonstrated that the transcriptional response to ATR-deficient proliferation was highly p53 dependent and markedly attenuated by p53 co-deletion. Acute ATR inhibition in vivo by nanoparticle-formulated VE-822 reproduced the developmental disruptions seen with Atr deletion. Genetic deletion of Atr blocked tumorigenesis in medulloblastomaprone SmoM2 mice. Our data show that p53-driven apoptosis and cell cycle arrest -and, in the absence of p53, non-apoptotic cell death -redundantly limit growth in ATR-deficient progenitors. These mechanisms may be exploited for treatment of CGNP-derived medulloblastoma using ATR inhibition.

New targets for brain tumor therapies may be identified by mutations that cause hereditary microcephaly. Brain growth depends on the repeated proliferation of stem and progenitor cells. Microcephaly syndromes result from mutations that specifically impair the ability of brain progenitor or stem cells to proliferate, by inducing either premature differentiation or apoptosis. Brain tumors that derive from brain progenitor or stem cells may share many of the specific requirements of their cells of origin. These tumors may therefore be susceptible to disruptions of the protein products of genes that are mutated in microcephaly. The potential for the products of microcephaly genes to be therapeutic targets in brain tumors are highlighted hereby reviewing research on EG5, KIF14, ASPM, CDK6, and ATR. Treatments that disrupt these proteins may open new avenues for brain tumor therapy that have increased efficacy and decreased toxicity.

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Ureteroarterial fistula is a rare condition wherein a communication develops between a ureter and the common, internal, or external iliac artery. Localizing the fistula can be difficult, as cystoscopy, CT angiography, and conventional angiography have low sensitivity in identifying the fistula. Provocative maneuvers within the ureter, however, can aid in the visualization of fistulae on angiography. Prior reports of endovascular repair have utilized transfemoral access, which makes performing concurrent provocative maneuvers in the ureter challenging. We present a case of successful endovascular ureteroarterial fistula localization and embolization in an 80-year-old woman with recurrent gross hematuria by the transradial approach, aided by concurrent provocative maneuvers performed via cystoscopy. The transradial endovascular approach facilitated a multi-disciplinary joint procedure that resulted in effective treatment of the patient.

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