Citations

Abstract Germ line mutations in several genes (BRCA1, BRCA2, and CHEK2) whose products are involved in the DNA damage–signaling pathway have been implicated in prostate cancer risk. To identify additional genes in this pathway that might confer susceptibility to this cancer, we analyzed a recently identified DNA damage–response gene, p53AIP1 (a gene encoding for p53-regulated apoptosis-inducing protein 1), for genetic variants in prostate cancer. Five novel germ line variants were identified. The two truncating variants (Ser32Stop and Arg21insG) were found in 3% (4 of 132) of unselected prostate tumor samples. Genotyping of the two variants in an additional 393 men with sporadic prostate cancer showed a frequency of 3.1% (12 of 393) in contrast to 0.6% (2 of 327) in 327 unaffected men (Fisher's exact test, P = 0.018), with an odds ratio (OR) of 5.1 [95% confidence interval (95% CI), 1.1-23.0]. In addition, two of six tumors carrying the truncating variants were associated with loss of heterozygosity of the wild-type alleles, suggesting that p53AIP1 may act as a tumor suppressor. We also showed that the truncated p53AIP1 was unable to induce apoptosis and suppress cell growth in HeLa and COS-7 cells. These results suggest that loss-of-function variants in p53AIP1 associated with the risk of sporadic prostate cancer and further support the concept that the genetic defects in the DNA damage–response genes play an important role in the development of prostate cancer. (Cancer Res 2006; 66(21): 10302-7)

In this article, we have characterized and compared gene expression profiles from laser capture microdissected neurons in six functionally and anatomically distinct regions from clinically and histopathologically normal aged human brains. These regions, which are also known to be differentially vulnerable to the histopathological and metabolic features of Alzheimer’s disease (AD), include the entorhinal cortex and hippocampus (limbic and paralimbic areas vulnerable to early neurofibrillary tangle pathology in AD), posterior cingulate cortex (a paralimbic area vulnerable to early metabolic abnormalities in AD), temporal and prefrontal cortex (unimodal and heteromodal sensory association areas vulnerable to early neuritic plaque pathology in AD), and primary visual cortex (a primary sensory area relatively spared in early AD). These neuronal profiles will provide valuable reference information for future studies of the brain, in normal aging, AD and other neurological and psychiatric disorders.

Human memory is a polygenic trait. We performed a genome-wide screen to identify memory-related gene variants. A genomic locus encoding the brain protein KIBRA was significantly associated with memory performance in three independent, cognitively normal cohorts from Switzerland and the United States. Gene expression studies showed that KIBRA was expressed in memory-related brain structures. Functional magnetic resonance imaging detected KIBRA allele–dependent differences in hippocampal activations during memory retrieval. Evidence from these experiments suggests a role for KIBRA in human memory.

Colorectal tumor DNA was examined for somatic instability at (CA) n repeats on human chromosomes 5q, 15q, 17p, and 18q. Differences between tumor and normal DNA were detected in 25 of the 90 (28 percent) tumors examined. This instability appeared as either a substantial change in repeat length (often heterogeneous in nature) or a minor change (typically two base pairs). Microsatellite instability was significantly correlated with the tumor's location in the proximal colon ( P = 0.003), with increased patient survival ( P = 0.02), and, inversely, with loss of heterozygosity for chromosomes 5q, 17p, and 18q. These data suggest that some colorectal cancers may arise through a mechanism that does not necessarily involve loss of heterozygosity.

Abstract Purpose: We have shown recently that glycogen synthase kinase-3 (GSK-3) β regulates nuclear factor-κB (NF-κB)–mediated pancreatic cancer cell survival and proliferation in vitro. Our objective was to determine the localization of GSK-3β in pancreatic cancer cells and assess the antitumor effect of GSK-3 inhibition in vivo to improve our understanding of the mechanism by which GSK-3β affects NF-κB activity in pancreatic cancer. Experimental Design: Immunohistochemistry and cytosolic/nuclear fractionation were done to determine the localization of GSK-3β in human pancreatic tumors. We studied the effect of GSK-3 inhibition on tumor growth, cancer cell proliferation, and survival in established CAPAN2 tumor xenografts using a tumor regrowth delay assay, Western blotting, bromodeoxyuridine incorporation, and terminal deoxynucleotidyl transferase–mediated dUTP nick end labeling. Results: We found nuclear accumulation of GSK-3β in pancreatic cancer cell lines and in 62 of 122 (51%) human pancreatic adenocarcinomas. GSK-3β nuclear accumulation is significantly correlated with human pancreatic cancer dedifferentiation. We have found that active GSK-3β can accumulate in the nucleus of pancreatic cancer cells and that inhibition of GSK-3 kinase activity represses its nuclear accumulation via proteasomal degradation within the nucleus. Lastly, we have found that inhibition of GSK-3 arrests pancreatic tumor growth in vivo and decreases NF-κB-mediated pancreatic cancer cell survival and proliferation in established tumor xenografts. Conclusions: Our results show the antitumor effect of GSK-3 inhibition in vivo, identify GSK-3β nuclear accumulation as a hallmark of poorly differentiated pancreatic adenocarcinoma, and provide new insight into the mechanism by which GSK-3β regulates NF-κB activity in pancreatic cancer.

Purpose Oxaliplatin, fluorouracil, and leucovorin are commonly used to treat advanced and resected colorectal cancer. This analysis compares the safety and efficacy of oxaliplatin plus fluorouracil/leucovorin administered bimonthly (FOLFOX4) in patients age younger than and at least 70 years. Patients and Methods This retrospective analysis included 3,742 colorectal cancer patients (614 age ≥ 70) from four clinical trials testing FOLFOX4 in the adjuvant, first-, and second-line settings. End points included grade ≥ 3 adverse events, response rate (in advanced disease), progression or relapse-free survival, dose-intensity, and overall survival in the studies with mature survival data. Results Grade ≥ 3 hematologic toxicity (neutropenia [43% v 49%; P = .04] and thrombocytopenia [2% v 5%; P = .04]) were significantly higher in older patients. Older age was not associated with increased rates of severe neurologic adverse events, diarrhea, nausea/vomiting, infection, overall incidence of grade ≥ 3 toxicity (63% v 67%; P = .15), or 60-day mortality (1.1% v 2.3%; P = .20). The relative benefit of FOLFOX4 versus control did not differ by age for response rate, progression or recurrence free-survival (hazard ratio, 0.70 for FOLFOX4 v control for age < 70, 0.65 for age ≥ 70; P = .42), or overall survival (hazard ratio, 0.77 age < 70, 0.82 age ≥ 70; P = .79). Dose-intensity did not differ by age at cycles 1, 3, 6, or 12. Conclusion FOLFOX4 maintains its efficacy and safety ratio in selected elderly patients with colorectal cancer. Its judicious use should be considered without regard to patient age, although scant data are available among patients older than 80 years.