Andrea Cortes

Hodgkin disease risk: Role of genetic polymorphisms and gene-gene interactions in inflammation pathway genes

Inflammation is a critical component of cancer development. The clinical and pathological features of Hodgkin disease (HD) reflect an abnormal immunity that results from cytokines secreted by Reed–Sternberg cells and the surrounding tumor. Numerous studies have reported the association between genetic polymorphisms in cytokine genes and the susceptibility to different hematologic cancers. However, the effects of such SNPs on modulating HD risk have not yet been investigated. We hypothesized that gene–gene interactions between candidate genes in the anti‐ and pro‐inflammatory pathways carrying suspicious polymorphisms may contribute to susceptibility to HD. To test this hypothesis, we conducted a study on 200 HD cases and 220 controls to assess associations between HD risk and 38 functional SNPs in inflammatory genes. We evaluated potential gene–gene interactions using a multi‐analytic strategy combining logistic regression, multi‐factor dimensionality reduction, and classification and regression tree (CART) approaches. We observed that, in combination, allelic variants in the COX2, IL18, ILR4, and IL10 genes modify the risk for developing HD. Moreover, the cumulative genetic risk score (CGRS) revealed a significant trend where the risk for developing HD increases as the number of adverse alleles in the cytokine genes increase. These findings support the notion that epigenetic‐interactions between these cytokines may influence pathogenesis of HD modulating the proliferation of regulatory T cells. In this way, the innate and adaptative immune responses may be altered and defy their usual functions in the host anti‐tumor response. Our study is the first to report the association between polymorphisms in inflammation genes and HD susceptibility risk. Mol. Carcinog.

Variants in folate pathway genes as modulators of genetic instability and lung cancer risk

Genetic instability plays a crucial role in cancer development. The genetic stability of the cell as well as DNA methylation status could be modulated by folate levels. Several studies suggested associations between polymorphisms in folate genes and alterations in protein expression and variations in serum levels of the folate. The objective of this study was to investigate the effect of folate pathway polymorphisms on modulating genetic instability and lung cancer risk. Genotyping of 5 SNPs in folate pathway genes and cytokinesis‐blocked micronucleus cytome assay analysis (to determine the genetic instability at baseline and following NNK treatment) was conducted on 180 lung cancer cases and 180 age‐, gender‐, and smoking‐matched controls. Our results showed that individually, folate pathway SNPs were not associated with cytogenetic damage or lung cancer risk. However, in a polygenic disease such as lung cancer, gene–gene interactions are expected to play an important role in determining the phenotypic variability of the diseases. We observed that interactions between MTHFR677, MTHFR1298, and SHMT polymorphisms may have a significant impact on genetic instability in lung cancer patients. With regard to cytogenetic alterations, our results showed that lymphocytes from lung cancer patients exposed to the tobacco‐specific carcinogen 4‐(methylnitrosamino)‐1‐(3‐pyridyl)‐1‐butanone [NNK] had considerably increased frequency of cytogenetic damage in presence of MTHFR 677, MTHFR 1298, and SHMT allelic variants. These findings support the notion that significant interactions may potentially modulate the lung cancer susceptibility and alter the overall the repair abilities of lung cancer patients when exposed to tobacco carcinogens such as NNK.

Rapid method for determination of DNA repair capacity in human peripheral blood lymphocytes amongst smokers

BackgroundDNA repair capacity is an important determinant of susceptibility to cancer. The hOGG1 enzyme is crucial for repairing the 8-oxoguanine lesion that occurs either as a byproduct of oxidative metabolism or as a result of exogenous sources such as exposure to cigarette smoke. It has been previously reported that smokers with low hOGG1 activity had significantly higher risk of developing lung cancer as compared to smokers with high hOGG1 activity.MethodsIn the current study we elucidate the association between plasma levels of 8-OHdG and the OGG1 repair capacity. We used the commercially available 8-OHdG ELISA (enzyme-linked immunosorbent assay), the Comet assay/FLARE hOGG1 (Fragment Length Analysis by Repair Enzymes) assay for quantification of the levels of 8-OHdG and measured the constitutive, induced and unrepaired residual damage, respectively. We compared the DNA repair capacity in peripheral blood lymphocytes following H2O2 exposure in 30 lung cancer patients, 30 non-, 30 former and 30 current smoker controls matched by age and gender.ResultsOur results show that lung cancer cases and current smoker controls have similar levels of 8-OHdG lesions that are significantly higher compared to the non-smokers controls. However, lung cancer cases showed significantly poorer repair capacity compared to all controls tested, including the current smokers controls. After adjustment for age, gender and family history of smoking-related cancer using linear regression, we observed a 5-fold increase in risk of lung cancer associated with high levels of residual damage/reduced repair capacity. Reduced OGG1 activity could be expected to be a risk factor in other smoking-related cancers.ConclusionOur study shows that the Comet/FLARE assay is a relatively rapid and useful method for determination of DNA repair capacity. Using this assay we could identify individuals with high levels of residual damage and hence poor repair capacity who would be good candidates for intensive follow-up and screening.

Hodgkin lymphoma risk: Role of genetic polymorphisms and gene–gene interactions in DNA repair pathways

DNA repair variants may play a potentially important role in an individuals susceptibility to developing cancer. Numerous studies have reported the association between genetic single nucleotide polymorphisms (SNPs) in DNA repair genes and different types of hematologic cancers. However, to date, the effects of such SNPs on modulating Hodgkin lymphoma (HL) risk have not yet been investigated. We hypothesized that gene–gene interaction between candidate genes in direct reversal, nucleotide excision repair (NER), base excision repair (BER) and double strand break (DSB) pathways may contribute to susceptibility to HL. To test this hypothesis, we conducted a study on 200 HL cases and 220 controls to assess associations between HL risk and 21 functional SNPs in DNA repair genes. We evaluated potential gene–gene interactions and the association of multiple polymorphisms in a chromosome region using a multi‐analytic strategy combining logistic regression, multi‐factor dimensionality reduction and classification and regression tree approaches. We observed that, in combination, allelic variants in the XPC Ala499Val, NBN Glu185Gln, XRCC3 Thr241Me, XRCC1 Arg194Trp, and XRCC1 399Gln polymorphisms modify the risk for developing HL. Moreover, the cumulative genetic risk score revealed a significant trend where the risk for developing HL increases as the number of adverse alleles in BER and DSB genes increase. These findings suggest that DNA repair variants in BER and DSB pathways may play an important role in the development of HL.

Tumor Endothelial Markers Define Novel Subsets of Cancer-Specific Circulating Endothelial Cells Associated with Antitumor Efficacy

Circulating endothelial cells (CEC) are derived from multiple sources, including bone marrow (circulating endothelial progenitors; CEP), and established vasculature (mature CEC). Although CECs have shown promise as a biomarker for patients with cancer, their utility has been limited, in part, by the lack of specificity for tumor vasculature and the different nonmalignant causes that can impact CEC. Tumor endothelial markers (TEM) are antigens enriched in tumor versus nonmalignant endothelia. We hypothesized that TEMs may be detectable on CEC and that these circulating TEM(+) endothelial cells (CTEC) may be a more specific marker for cancer and tumor response than standard CEC. We found that tumor-bearing mice had a relative increase in numbers of circulating CTEC, specifically with increased levels of TEM7 and TEM8 expression. Following treatment with various vascular-targeting agents, we observed a decrease in CTEC that correlated with the reductions in tumor growth. We extended these findings to human clinical samples and observed that CTECs were present in patients with esophageal cancer and non-small cell lung cancer (N = 40), and their levels decreased after surgical resection. These results demonstrate that CTECs are detectable in preclinical cancer models and patients with cancer. Furthermore, they suggest that CTECs offer a novel cancer-associated marker that may be useful as a blood-based surrogate for assessing the presence of tumor vasculature and antiangiogenic drug activity.

Endothelial progenitor cell mobilization by preoperative exercise: a bone marrow response associated with postoperative outcome

BACKGROUND Preoperative anaemia is associated with increased morbidity in patients undergoing major surgery. Whether erythrocytes are the only bone-marrow-derived cell lineage that associates with increased surgical complications is unknown. This prospective observational trial studied the mobilization of endothelial progenitor cells (EPCs) in response to exercise in association with postoperative complications. METHODS After IRB approval, 60 subjects undergoing major thoracic surgery were exercised to exhaustion (peak V̇(O₂)). Peripheral blood collected before and after peak exercise was quantified for EPC lineages by fluorescence-activated cell sorter analysis. Complication analysis was based on the Clavien-Dindo classification. RESULTS Exhaustive exercise increased EPC [CD45-133+34+ cells=150 (0.00-5230) to 220 (0.00-1270) cells μl(-1); median change (range)=20 (-4,180-860) cells μl(-1); P=0.03] but not mature endothelial cell (EC) subpopulations. Pre-exercise levels [odds ratio (OR)=0.86, 95% confidence interval (CI): 0.37-2.00, P=0.72), change after exercise as a continuous variable (OR=0.95, 95% CI: 0.41-2.22, P=0.91) and a positive response after exercise (change >0 cells μl(-1); OR=0.41, 95% CI: 0.13-1.28, P=0.12) were not statistically significantly associated with the incidence of postoperative complications. Post-hoc receiver operating characteristic curve analyses revealed that subjects with a CD45-133+34+ increase ≥60 cells μl(-1) in response to exercise suffered fewer postoperative complications [86% sensitivity, 48% specificity and AUC=0.67 (95% CI: 0.52-0.81)]. CONCLUSIONS Preoperative exercise induces EPC into the peripheral circulation. Subjects with a poor EPC response had a pre-existing propensity for postoperative complications. This warrants further research into the role of bone marrow function as a critical component to endothelial repair mechanisms. CLINICAL TRIAL REGISTRATION IRB 2003-0434 (University of Texas M.D. Anderson Cancer Center, Houston, TX, USA).

Effects of CDK4/6 Inhibition in Hormone Receptor-Positive/Human Epidermal Growth Factor Receptor 2-Negative Breast Cancer Cells with Acquired Resistance to Paclitaxel

Among patients with hormone receptor (HR)-positive breast cancer, those with residual disease after neoadjuvant chemotherapy have a higher risk of relapse and poorer survival than those with a complete response. Previous studies have revealed a correlation between activation of cell cycle-regulating pathways in HR-positive breast cancer, particularly cyclin-dependent kinase (CDK) 4 and 6/cyclin D1 signaling, and resistance to standard therapies. Although CDK4/6 inhibition by palbociclib in combination with endocrine therapy has shown potent antiproliferative effects in HR-positive/human epidermal growth factor receptor 2 (HER2)-negative breast cancer, the potential role of palbociclib in re-sensitizing chemotherapy-resistant HR-positive breast cancer is not well defined. We hypothesized that CDK4/6 inhibition by palbociclib re-sensitizes HR-positive/HER2-negative residual breast cancer to taxane-based adjuvant therapy. Using cell counting, flow cytometry, and western blotting, we evaluated the efficacy of palbociclib alone and in concurrent or sequential combination with paclitaxel in parental and paclitaxel-resistant T47D HR-positive/HER2-negative breast cancer cells. The CDK4/6 pathway was constitutively active in both parental and paclitaxel-resistant T47D cells; thus, both cell types were highly sensitive to the inhibitory effects of single-agent palbociclib on cell growth and cell cycle progression. However, palbociclib did not re-sensitize resistant cells to paclitaxel-induced G2/M arrest and cell death in any of the combinations tested. Our results suggest that CDK4/6 inhibition by palbociclib does not re-sensitize HR-positive/HER2-negative residual breast cancer to chemotherapy. Nevertheless, the fact that CDK4/6 activation remained intact in paclitaxel-resistant cells indicates that patients who have HR-positive/HER2-negative residual disease after taxane-based neoadjuvant chemotherapy may still benefit from palbociclib in combination with other regimens, such as endocrine therapies, for adjuvant therapy.

Characteristics of percutaneous core biopsies adequate for next generation genomic sequencing

Purpose Determine the characteristics of percutaneous core biopsies that are adequate for a next generation sequencing (NGS) genomic panel. Materials and methods All patients undergoing percutaneous core biopsies in interventional radiology (IR) with samples evaluated for a 46-gene NGS panel during 1-year were included in this retrospective study. Patient and procedure variables were collected. An imaging-based likelihood of adequacy score incorporating targeting and sampling factors was assigned to each biopsied lesion. Univariate and multivariate logistic regression was performed. Results 153 patients were included (58.2% female, average age 59.5 years). The most common malignancy was lung cancer (40.5%), most common biopsied site was lung (36%), and average size of biopsied lesions was 3.8 cm (+/- 2.7). Adequacy for NGS was 69.9%. Univariate analysis showed higher likelihood of adequacy score (p = 0.004), primary malignancy type (p = 0.03), and absence of prior systemic therapy (p = 0.018) were associated with adequacy for NGS. Multivariate analysis showed higher adequacy for lesions with likelihood of adequacy scored 3 (high) versus lesions scored 1 (low) (OR, 7.82; p = 0.002). Melanoma lesions had higher adequacy for NGS versus breast cancer lesions (OR 9.5; p = 0.01). Absence of prior systemic therapy (OR, 6.1; p = 0.02) and systemic therapy 3 months before biopsy yielded greater adequacy for NGS. Lesions <3 cm had greater adequacy for NGS than larger lesions (OR 2.72, p = 0.02). Conclusion As targeted therapy becomes standard for more cancers, percutaneous biopsy specimens adequate for NGS genomic testing will be needed. An imaging-based likelihood of adequacy score assigned by IR physicians and other pre-procedure variables can help predict the likelihood of biopsy adequacy for NGS.

Abstract 2873: Imaging tumor heterogeneity after multikinase inhibitor therapy in rat hepatocellular carcinoma

Purpose To assess tumor tissue perfusion and vascular permeability through multiparametric functional imaging, and to evaluate their correspondence with histopathologic parameters of necrosis and hypoxia in a rat model of hepatocellular carcinoma treated with a multikinase inhibitor. Materials and Methods Rat hepatoma McA-RH7777 cells were implanted in the left liver lobe of nineteen male Buffalo rats. Exactly 2 weeks after tumor inoculation, the animals were randomly assigned to remain untreated (n=10) or to receive a daily dose of 7.5 mg/kg sorafenib by oral gavage (n=9) for 2 additional weeks. T2-weighted spin-echo magnetic resonance imaging (MRI), dynamic contrast-enhanced (DCE) and contrast-enhanced ultrasound (CEUS) were performed weekly. All tumors were harvested 4 weeks post-implantation >90 minutes after injecting 60mg/kg pimonidazole. Tissue sections were stained for hematoxylin-eosin and pimonidazole for quantitative assessment of necrosis and hypoxia, respectively. Differences between treatment groups were assessed using the Mann-Whitney test, and the correlation of imaging and histopathology parameters was determined by Spearman correlation analysis. Results In spite of the relatively low dose and short treatment duration, the response to sorafenib therapy was characterized by a significantly higher median tumor necrosis (60 vs 15%, P Conclusion Tumors exhibited wide heterogeneity in vascular perfusion and hypoxia after treatment. Interestingly, functional MRI parameters appear to correlate more strongly with tissue oxygenation, whereas functional CEUS parameters correlate with tumor viability. Novel predictive imaging biomarkers of treatment response may be developed through further analyses of spatial tumor heterogeneity in our animal model. Citation Format: Nina M. Munoz, Adeeb A. Minhaj, Kiersten L. Maldonado, Charles Kingsley, Hideyuki Nishiofuku, Keith A. Michel, Andrea C. Cortes, James A. Bankson, Asif Rashid, Rony Avritscher. Imaging tumor heterogeneity after multikinase inhibitor therapy in rat hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2873. doi:10.1158/1538-7445.AM2017-2873

Ex Vivo Confocal Fluorescence Microscopy for Rapid Evaluation of Tissues in Surgical Pathology Practice

CONTEXT - Optical imaging techniques are currently available for imaging tissues without the need for any type of extensive tissue preparation. There are several applications for their potential use in surgical pathology practice. OBJECTIVE - To evaluate the feasibility of using a confocal fluorescence microscopy (CFM) platform for ex vivo examination of tissues obtained from surgical resections of breast, lung, kidney, and liver. DESIGN - Tissue fragments (0.5-1.0 cm) were immersed in 0.6 mM acridine orange for 6 seconds and imaged using a CFM platform at a 488-nm wavelength. The imaged tissues were subsequently fixed in formalin and processed routinely to generate hematoxylin-eosin-stained tissue sections. Mosaics of the grayscale CFM images were studied at different magnifications for recognition of the tissue and were compared with conventional histopathologic examination of hematoxylin-eosin tissue sections. RESULTS - We imaged 55 tissue fragments obtained from 16 breast (29%), 18 lung (33%), 14 kidney (25%), and 7 liver (13%) surgical excision specimens. Acridine orange labeled the nuclei, creating the contrast between nucleus and cytoplasm and thereby recapitulating the tissue architecture. We could obtain CFM images of good quality within 5 to 10 minutes that allowed recognition of the cytomorphologic details for categorization of the imaged tissue and were similar to histologic examination of hematoxylin-eosin tissue sections. CONCLUSIONS - The ease and speed of acquisition of CFM images together with the resolution and resemblance of the CFM images to hematoxylin-eosin sections suggest that the CFM platform has excellent potential for use in surgical pathology practice.