Shama Buch

Therapeutic equivalence in survival for hepatic arterial chemoembolization and yttrium 90 microsphere treatments in unresectable hepatocellular carcinoma: a two-cohort study.

Intrahepatic arterial yttrium 90 (90Y) microspheres have been proposed as a less toxic, less invasive therapeutic option to transhepatic arterial chemoembolization (TACE) for patients with surgically unresectable hepatocellular carcinoma (HCC). TACE has demonstrated the ability to prolong survival. However, long‐term survival remains uncertain.

Bioequivalence revisited: Influence of age and sex on CYP enzymes

The activity of cytochrome P450 (CYP) enzymes, which determine the rate of elimination of lipid‐soluble drugs, demonstrates considerable interindividual variability. The extent to which age and sex influence CYP activity remains unclear in humans. Our objectives were to determine whether in vivo activity of selected CYP enzymes is affected by age or sex and to evaluate sex bioequivalence in a large sample size.

Genome-Wide Association Study of Survival in Non–Small Cell Lung Cancer Patients Receiving Platinum-Based Chemotherapy

BACKGROUND Interindividual variation in genetic background may influence the response to chemotherapy and overall survival for patients with advanced-stage non-small cell lung cancer (NSCLC). METHODS To identify genetic variants associated with poor overall survival in these patients, we conducted a genome-wide scan of 307,260 single-nucleotide polymorphisms (SNPs) in 327 advanced-stage NSCLC patients who received platinum-based chemotherapy with or without radiation at the University of Texas MD Anderson Cancer Center (the discovery population). A fast-track replication was performed for 315 patients from the Mayo Clinic followed by a second validation at the University of Pittsburgh in 420 patients enrolled in the Spanish Lung Cancer Group PLATAX clinical trial. A pooled analysis combining the Mayo Clinic and PLATAX populations or all three populations was also used to validate the results. We assessed the association of each SNP with overall survival by multivariable Cox proportional hazard regression analysis. All statistical tests were two-sided. RESULTS SNP rs1878022 in the chemokine-like receptor 1 (CMKLR1) was statistically significantly associated with poor overall survival in the MD Anderson discovery population (hazard ratio [HR] of death = 1.59, 95% confidence interval [CI] = 1.32 to 1.92, P = 1.42 × 10(-6)), in the PLATAX clinical trial (HR of death = 1.23, 95% CI = 1.00 to 1.51, P = .05), in the pooled Mayo Clinic and PLATAX validation (HR of death = 1.22, 95% CI = 1.06 to 1.40, P = .005), and in pooled analysis of all three populations (HR of death = 1.33, 95% CI = 1.19 to 1.48, P = 5.13 × 10(-7)). Carrying a variant genotype of rs10937823 was associated with decreased overall survival (HR of death = 1.82, 95% CI = 1.42 to 2.33, P = 1.73 × 10(-6)) in the pooled MD Anderson and Mayo Clinic populations but not in the PLATAX trial patient population (HR of death = 0.96, 95% CI = 0.69 to 1.35). CONCLUSION These results have the potential to contribute to the future development of personalized chemotherapy treatments for individual NSCLC patients.

Case-control study of oral and oropharyngeal cancer in whites and genetic variation in eight metabolic enzymes.

Genetic variation in xenobiotic metabolizing enzymes may explain differing susceptibilities to the cancer causing effects of tobacco and alcohol.

Tumor and liver determinants of prognosis in unresectable hepatocellular carcinoma: A case cohort study

Background and Aims:  A total of 967 patients with unresectable and untransplantable, biopsy‐proven hepatocellular carcinoma (HCC) were prospectively evaluated at baseline and followed up till death.

XPF expression correlates with clinical outcome in squamous cell carcinoma of the head and neck

Purpose: Tumor-specific biomarkers that predict resistance to DNA damaging agents may improve therapeutic outcomes by guiding the selection of effective therapies and limiting morbidity related to ineffective approaches. XPF (ERCC4) is an essential component of several DNA repair pathways and XPF-deficient cells are exquisitely sensitive to DNA damaging agents. The purpose of this study was to determine whether XPF expression levels predict clinical response to DNA damaging agents in head and neck squamous cell carcinoma (HNSCC). Experimental Design: Quantitative immunohistochemistry was used to measure XPF expression in tumors from a cohort of 80 patients with newly diagnosed HNSCC treated with radiation therapy with or without platinum-based chemotherapy; samples were collected prospectively. Genomic DNA isolated from blood samples was analyzed for nine single nucleotide polymorphisms (SNP) in the XPF gene by using a custom array. The primary endpoint was progression-free survival (PFS). Results: XPF expression was higher in tumors from the oral cavity than from the other sites (P < 0.01). High XPF expression correlated with early time to progression both by univariate (HR = 1.87, P = 0.03) and multivariate analysis (HR = 1.83, P = 0.05). The one year PFS for high expressers was 47% (95% CI = 31–62) compared with 72% (95% CI = 55–83) for low expressers. In addition, we identified four XPF SNPs that showed marginal association with treatment failure. Conclusions: Expression level of XPF in HNSCC tumors correlates with clinical response to DNA damaging agents. XPF has potential to guide next generation personalized cancer therapy. Clin Cancer Res; 17(16); 5513–22. ©2011 AACR.

Genetic variability in DNA repair and cell cycle control pathway genes and risk of smoking-related lung cancer

DNA repair and cell cycle control play an important role in the repair of DNA damage caused by cigarette smoking. Given this role, functionally relevant single nucleotide polymorphisms (SNPs) in genes in these pathways may well affect the risk of smoking‐related lung cancer. We examined the relationship between 240 SNPs in DNA repair and cell cycle control pathway genes and lung cancer risk in a case–control study of white current and ex‐cigarette smokers (722 cases and 929 controls). Additive, dominant, and recessive genetic models were evaluated for each SNP. A genetic risk summary score was also constructed. Odds ratios (OR) for lung cancer risk and 95% confidence intervals (95% CI) were estimated using logistic regression models. Thirty‐eight SNPs were associated with lung cancer risk in our study population at P < 0.05. The strongest associations were observed for rs2074508 in GTF2H4 (Padditive = 0.003), rs10500298 in LIG1 (Precessive = 2.7 × 10−4), rs747658 and rs3219073 in PARP1 (rs747658: Padditive = 5.8 × 10−5; rs3219073: Padditive = 4.6 × 10−5), and rs1799782 and rs3213255 in XRCC1 (rs1799782: Pdominant = 0.006; rs3213255: Precessive = 0.004). Compared to individuals with first quartile (lowest) risk summary scores, individuals with third and fourth quartile summary score results were at increased risk for lung cancer (OR: 2.21, 95% CI: 1.66–2.95 and OR: 3.44, 95% CI: 2.58–4.59, respectively; Ptrend < 0.0001). Our data suggests that variation in DNA repair and cell cycle control pathway genes is associated with smoking‐related lung cancer risk. Additionally, combining genotype information for SNPs in these pathways may assist in classifying current and ex‐cigarette smokers according to lung cancer risk.

Association of polymorphisms in the cyclin D1 and XPD genes and susceptibility to cancers of the upper aero-digestive tract.

DNA repair enzyme genetic polymorphisms have been postulated to increase the risk of certain cancers in the presence of tobacco carcinogen exposures. The XPD protein is an important component of the TFIIH transcription factor complex. XPD genetic polymorphisms resulting in amino acids substitutions may lead to alterations in TFIIH helicase activity, resulting in repair and transcription defects. Cyclin D1 is a key regulatory protein for the transition of cells from the G1‐S cell cycle phase. The CCND1 G870A polymorphism has been reported to enhance alternate splicing of a stable mRNA variant, which may result in the bypass of the G1/S cell cycle checkpoint. In this study, XPD G23591A (Asp312Asn) and A35931C (Lys751Gln) polymorphisms and the CCND1 G870A splice variant frequencies were determined in 273 upper aero‐digestive tract cancer cases and 269 controls. The XPD Asp312Asn variant frequency was significantly different among cases and controls and conferred an odds ratio (OR) of 1.3 (95% CI 1.0–1.8). However, individuals with the CCND1 G870A and XPD Lys751Gln variants had higher age adjusted ORs of 3.2 (95% CI 2.2–4.6) and 2.2 (95% CI 1.5–3.2), respectively. Furthermore, a significant gene–gene interaction was observed among cases with at least two variant alleles for both CCND1 and XPD genes [OR 7.09 (95% CI 4.03–12.5)]. Smokers with a combination of at least one variant allele of both CCND1 and XPD genes also had an elevated risk as compared to nonsmokers. This is the first study to suggest an associative interaction between XPD and CCND1 genetic polymorphisms, tobacco exposure, and cancer risk.

CYP24 inhibition preserves 1α,25-dihydroxyvitamin D3 anti-proliferative signaling in lung cancer cells

Human lung tumors aberrantly express the 1α,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3))-catabolizing enzyme, CYP24. We hypothesized that CYP24 reduces 1,25(OH)(2)D(3)-mediated transcription and allows lung cancer cells to escape its growth-inhibitory action. To test this, H292 lung cancer cells and the CYP24-selective inhibitor CTA091 were utilized. In H292 cells, CTA091 reduces 1,25(OH)(2)D(3) catabolism, significantly increases 1,25(OH)(2)D(3)-mediated growth inhibition, and increases 1,25(OH)(2)D(3) effects on induced and repressed genes in gene expression profiling studies. Pathway mapping of repressed genes uncovered cell cycle as a predominant 1,25(OH)(2)D(3) target. In H292 cells, 1,25(OH)(2)D(3) significantly decreases cyclin E2 levels and induces G(0)/G(1) arrest. A broader set of cyclins is down-regulated when 1,25(OH)(2)D(3) is combined with CTA091, and cell cycle arrest further increases. Effects of CTA091 on 1,25(OH)(2)D(3) signaling are vitamin D receptor-dependent. These data provide evidence that CYP24 limits 1,25(OH)(2)D(3) anti-proliferative signaling in cancer cells, and suggest that CTA091 may be beneficial in preserving 1,25(OH)(2)D(3) action in lung cancer.

A sex-specific association between a 15q25 variant and upper aerodigestive tract cancers

Background: Sequence variants located at 15q25 have been associated with lung cancer and propensity to smoke. We recently reported an association between rs16969968 and risk of upper aerodigestive tract (UADT) cancers (oral cavity, oropharynx, hypopharynx, larynx, and esophagus) in women (OR = 1.24, P = 0.003) with little effect in men (OR = 1.04, P = 0.35). Methods: In a coordinated genotyping study within the International Head and Neck Cancer Epidemiology (INHANCE) consortium, we have sought to replicate these findings in an additional 4,604 cases and 6,239 controls from 10 independent UADT cancer case–control studies. Results: rs16969968 was again associated with UADT cancers in women (OR = 1.21, 95% CI = 1.08–1.36, P = 0.001) and a similar lack of observed effect in men [OR = 1.02, 95% CI = 0.95–1.09, P = 0.66; P-heterogeneity (Phet) = 0.01]. In a pooled analysis of the original and current studies, totaling 8,572 UADT cancer cases and 11,558 controls, the association was observed among females (OR = 1.22, 95% CI = 1.12–1.34, P = 7 × 10−6) but not males (OR = 1.02, 95% CI = 0.97–1.08, P = 0.35; Phet = 6 × 10−4). There was little evidence for a sex difference in the association between this variant and cigarettes smoked per day, with male and female rs16969968 variant carriers smoking approximately the same amount more in the 11,991 ever smokers in the pooled analysis of the 14 studies (Phet = 0.86). Conclusions: This study has confirmed a sex difference in the association between the 15q25 variant rs16969968 and UADT cancers. Impact: Further research is warranted to elucidate the mechanisms underlying these observations. Cancer Epidemiol Biomarkers Prev; 20(4); 658–64. ©2011 AACR.