Citations

Abstract A recent genome-wide association study found that genetic variants on chromosomes 3, 6, 7, 10, 11, 19 and X were associated with prostate cancer risk. We evaluated the most significant single-nucleotide polymorphisms (SNP) in these loci using a worldwide consortium of 13 groups (PRACTICAL). Blood DNA from 7,370 prostate cancer cases and 5,742 male controls was analyzed by genotyping assays. Odds ratios (OR) associated with each genotype were estimated using unconditional logistic regression. Six of the seven SNPs showed clear evidence of association with prostate cancer (P = 0.0007-P = 10−17). For each of these six SNPs, the estimated per-allele OR was similar to those previously reported and ranged from 1.12 to 1.29. One SNP on 3p12 (rs2660753) showed a weaker association than previously reported [per-allele OR, 1.08 (95% confidence interval, 1.00-1.16; P = 0.06) versus 1.18 (95% confidence interval, 1.06-1.31)]. The combined risks associated with each pair of SNPs were consistent with a multiplicative risk model. Under this model, and in combination with previously reported SNPs on 8q and 17q, these loci explain 16% of the familial risk of the disease, and men in the top 10% of the risk distribution have a 2.1-fold increased risk relative to general population rates. This study provides strong confirmation of these susceptibility loci in multiple populations and shows that they make an important contribution to prostate cancer risk prediction. (Cancer Epidemiol Biomarkers Prev 2008;17(8):2052–61)

Abstract Purpose: Although the prognostic value of B7-H1 and B7-H4 expression by tumor cells in clear cell renal cell carcinoma (ccRCC) has been established, the role of B7-H3 is unknown. As such, we evaluated the association of B7-H3 expression with clinicopathologic outcomes in patients treated for ccRCC. Experimental Design: Nephrectomy specimens from 743 consecutive patients treated for ccRCC at our institution from 1990 to 1999 were evaluated for B7-H3 expression by immunohistochemical staining. Associations of B7-H3 expression with clinical and pathologic features were evaluated using χ2 and Fisher's exact tests. Associations of B7-H3 expression with death from RCC were evaluated using Cox proportional hazards regression models. Results: B7-H3 expression by tumor cells or tumor vasculature was noted in 17% and 95% of specimens, respectively. The presence of either tumor cell or diffuse tumor vasculature expression of B7-H3 was present in 46% of specimens and was associated with multiple adverse clinical and pathologic features. After multivariable adjustment, the presence of either tumor cell or diffuse tumor vasculature B7-H3 expression was significantly associated with an increased risk of death from RCC (risk ratio, 1.38; 95% confidence interval, 1.03-1.84; P = 0.029). Conclusions: Both tumor cell and tumor vasculature B7-H3 expression convey important information to predict ccRCC outcomes. Collectively, our past and present studies pertaining to B7-H ligand expression indicate that ccRCC may use redundant mechanisms to compromise host antitumoral immunity. Future studies will focus on the effect of combined B7-H ligand expression in RCC.

Abstract AZD6244 (ARRY 142886) is a potent and selective mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) kinase (MEK) inhibitor currently in early clinical trials. We examined the activity of AZD6244 in a panel of non–small cell lung cancer and a panel of cell lines representing many cancer types using in vitro growth assays. AZD6244 induced G0-G1 cell cycle arrest in sensitive cell lines that primarily included cells containing the BRAF V600E mutation. In these cells, G0-G1 arrest is accompanied by the up-regulation of the cell cycle inhibitors p21WAF1 and p27Kip1 and down-regulation of cyclin D1. In the majority of cell lines tested, including those with K-ras or non-V600E BRAF mutations, AZD6244 induced the accumulation of phospho-MEK, an effect not observed in the most sensitive BRAF V600E-containing cells. Accumulation of phospho-MEK in non–V600E-containing cell lines is due to abrogation of negative feedback pathways. BRAF V600E disrupts negative feedback signaling, which results in enhanced baseline phospho-MEK expression. Exogenous expression of BRAF V600E disrupts feedback inhibition but does not sensitize cells to AZD6244. Specific suppression of endogenous BRAF V600E does not confer resistance to AZD6244 but enhances sensitivity to AZD6244. Thus, our findings show that BRAF V600E marks cells with an in vitro requirement for MAPK signaling to support proliferation. These cells are exquisitely sensitive to AZD6244 (IC50, <100 nmol/L), have high baseline levels of phospho-MEK, and lack feedback inhibition between ERK and Raf. These data suggest an approach to identifying cells that may be sensitive to AZD6244 and other MEK inhibitors. [Cancer Res 2008;68(15):6145–53]

Abstract Purpose: Aberrant expression of T-cell coregulatory molecules has been investigated as a mechanism by which certain cancers may evade host immune surveillance. We evaluated expression of the T-cell coregulators B7-H1, B7-H3, and PD-1 in urothelial cell carcinoma (UCC) of the bladder. Experimental Design: Immunohistochemistry for B7-H1, B7-H3, and PD-1 was done on paraffin-embedded sections from 318 consecutive patients with UCC who underwent radical cystectomy. Expression was correlated with clinicopathologic outcomes and postoperative survival. Results: B7-H3 was widely expressed in UCC, as 222 of 314 (70.7%) tumors showed positive staining. Expression of B7-H3 in UCC was significantly increased compared with adjacent, nontumor urothelium, as a median of 70% of tumor cells expressed B7-H3, compared with 20% of cells in nontumor specimens (P < 0.001). The increase in B7-H3 expression was independent of tumor stage (P = 0.13). Expression of B7-H1 by UCC tumors (P < 0.001) and PD-1 by tumor-infiltrating lymphocytes (P = 0.012) were significantly associated with increased pathologic stage. Patients who had received intravesical bacillus Calmette-Guerin before cystectomy tended to show increased expression of B7-H3 (P = 0.023) and PD-1 (P = 0.071) but were less likely to express B7-H1 (P = 0.027). Moreover, for the subset of patients with organ-confined disease (n = 167), B7-H1 expression independently predicted all-cause mortality after cystectomy (hazard ratio, 3.18; 95% confidence interval, 1.74-5.79; P < 0.001). Conclusions: B7-H3 is highly expressed in UCC across tumor stages, whereas B7-H1 and PD-1 expression are associated with advanced disease. B7-H1 expression predicts mortality after cystectomy for patients with organ-confined tumors. These molecules may represent novel diagnostic or prognostic markers, as well as therapeutic targets, for patients with UCC.