Frequency and clinicopathologic correlates of KRAS amplification in non-small cell lung carcinoma

Background

Characterization of the non-small cell lung cancer (NSCLC) genome has suggested that KRAS amplification is one of the commonest molecular abnormalities in NSCLC. However, the prevalence and clinicopathologic significance of KRAS amplification, and its relationship with KRAS activating mutations have not been well-defined. The purpose of this study was to establish the prevalence of KRAS amplification in two separate, large NSCLC cohorts, to define the clinicopathologic features of KRAS-amplified NSCLC in a single uniformly treated cohort, and to investigate the interplay between KRAS amplification and KRAS mutation.

Methods

Fluorescence in situ hybridization was utilized to detect KRAS amplification on tissue microarrays constructed from a Swiss cohort of 538 NSCLCs and a series of 402 patients with NSCLC treated in a single institution in New York. DNA sequencing to detect KRAS codon 12 activating mutations was performed on a subset of tumors. Amplification and mutation status were compared with patient baseline characteristics, tumor characteristics, and overall- and disease-free survival.

Results

The prevalence of KRAS amplification was 13.7% in the Swiss cohort and 15.1% in the New York cohort. Among adenocarcinomas, KRAS amplification was associated with larger (mean size 2.8 ± 1.8 cm vs. 2.1 ± 1.3 cm, p = 0.003), less well-differentiated tumors (18% vs. 42%, p = 0.004) that were more likely to be invasive (95% vs. 77%, p = 0.004) and to exhibit angiolymphatic invasion (24% vs. 12%, p = 0.04). These differences were statistically significant within the subset of adenocarcinomas harboring activating KRAS mutations, suggesting a synergistic relationship between amplification and mutation. No significant association between KRAS amplification and nodal metastasis or survival was seen.

Conclusions

KRAS amplification is a common molecular alteration in NSCLC, characterizing ∼15% of tumors. This alteration is associated with indicators of local aggressiveness, and may act synergistically with KRAS mutations to promote tumor progression.     

Therapeutic targeting of the mitotic spindle checkpoint through nanoparticle-mediated siRNA delivery inhibits tumor growth in vivo

We investigated IgA and IgG levels against EBV viral capsid antigen (VCA) and nuclear antigen-1 (EBNA-1) in serum of 223 women with breast cancer (BC) and 309 controls in Guangzhou, China. VCA IgA levels were significantly associated with an elevated risk of BC, with adjusted ORs (95%CIs) of 1.70 (1.05-2.76) (seropositivity) and 2.21 (1.11-4.40) (unit increases in OD value). This association was stronger among young, lean, and HER2+ women. The EBNA-1 IgA levels in OD value, but not seropositivity, were associated with an increased risk of BC among ER+, PR+, and HER2+ patients. None of the IgG variables was related to BC. These results suggest the EBV association with BC in an endemic area of nasopharyngeal carcinoma.     

Stabilizing sodium hypochlorite at high pH: effects on soft tissue and dentin

Introduction

When sodium hypochlorite solutions react with tissue, their pH drops and tissue sorption decreases. We studied whether stabilizing a NaOCl solution at a high pH would increase its soft-tissue dissolution capacity and effects on the dentin matrix compared with a standard NaOCl solution of the same concentration and similar initial pH.

Methods

NaOCl solutions were prepared by mixing (1:1) a 10% stock solution with water (standard) or 2 mol/L NaOH (stabilized). Physiological saline and 1 mol/L NaOH served as the controls. Chlorine content and alkaline capacity of NaOCl solutions were determined. Standardized porcine palatal soft-tissue specimens and human root dentin bars were exposed to test and control solutions. Weight loss percentage was assessed in the soft-tissue dissolution assay. Three-point bending tests were performed on the root dentin bars to determine the modulus of elasticity and flexural strength. Values between groups were compared using one-way analysis of variance with the Bonferroni correction for multiple testing (α < .05).

Results

Both solutions contained 5% NaOCl. One milliliter of the standard and the stabilized solution consumed 4.0 mL and 13.7 mL of a 0.1-mol/L HCl solution before they reached a pH level of 7.5, respectively. The stabilized NaOCl dissolved significantly more soft tissue than the standard solution, and the pH remained high. It also caused a higher loss in elastic modulus and flexure strength (P < .05) than the control solutions, whereas the standard solution did not.

Conclusions

NaOH-stabilized NaOCl solutions have a higher alkaline capacity and are thus more proteolytic than standard counterparts.     

Cytotoxic effects of combination of oxidosqualene cyclase inhibitors with atorvastatin in human cancer cells

Ten oxidosqualene cyclase inhibitors with high efficacy as cholesterol-lowering agents and of different chemical structure classes were evaluated as potential anticancer agents against human cancer cells from various tissue origins and nontumoral human-brain-derived endothelial cells. Inhibition of cancer cell growth was demonstrated at micromolar concentrations, comparable to the concentrations of statins necessary for antitumor effect. Human glioblastoma cells were among the most sensitive cells. These compounds were also able to decrease the proliferation of angiogenic brain-derived endothelial cells, as a model of tumor-induced neovasculation. Additive effects in human glioblastoma cells were also demonstrated for oxidosqualene cyclase inhibitors in combination with atorvastatin while maintaining selectivity against endothelial cells. Thus, not only statins targeting the 3-hydroxy-3-methylglutaryl coenzyme A reductase but also inhibitors of oxidosqualene cyclase decrease tumor growth, suggesting new therapeutic opportunities of combined anti-cholesterol agents for dual treatment of glioblastoma.     

High resolution ArrayCGH and expression profiling identifies PTPRD and PCDH17/PCH68 as tumor suppressor gene candidates in laryngeal squamous cell carcinoma

Many classical tumor suppressor genes (TSG) were identified by delineation of bi-allelic losses called homozygous deletions. To identify systematically homozygous deletions in laryngeal squamous cell carcinoma (LSCC) and to unravel novel putative tumor suppressor genes, we screened 10 LSCC cell lines using high resolution array comparative genomic hybridization (arrayCGH) and array based expression analysis. ArrayCGH identified altogether 113 regions harboring protein coding genes that showed strong reduction in copy number indicating a potential homozygous deletion. Out of the 113 candidate regions, 22 novel homozygous deletions that affected the coding sequences of 15 genes were confirmed by multiplexPCR. Three genes were homozygously lost in two cell lines: PCDH17/PCH68, PRR20, and PTPRD. For the 15 homozygously deleted genes, four showed statistically significant downregulation of expression in LSCC cell lines as compared with normal human laryngeal controls. These were ATG7 (1/10 cell line), ZMYND11 (BS69) (1/10 cell line), PCDH17/PCH68 (9/10 cell lines), and PTPRD (7/10 cell lines). Quantitative real-time PCR was used to confirm the downregulation of the candidate genes in 10 expression array-studied cell lines and an additional cohort of cell lines; statistical significant downregulation of PCDH17/PCH68 and PTPRD was observed. In line with this also Western blot analyses demonstrated a complete absence of the PCDH17 and PTPRD proteins. Thus, expression profiling confirmed recurrent alterations of two genes identified primarily by delineation of homozygous deletions. These were PCDH17/PCH68, the protocadherin gene, and the STAT3 inhibiting receptor protein tyrosine phosphatase gene PTPRD. These genes are good candidates for novel TSG in LSCC.