Identification and functional analysis of 9p24 amplified genes in human breast cancer

Previously, our group identified a novel amplicon at chromosome 9p24 in human esophageal and breast cancers, and cloned the novel gene, GASC1 (gene amplified in squamous cell carcinoma 1, also known as JMJD2C/KDM4C), from this amplicon. GASC1 is a histone demethylase involved in the deregulation of histone methylation in cancer cells. In the current study, we aimed to comprehensively characterize the genes in the 9p24 amplicon in human breast cancer. We performed extensive genomic analyses on a panel of cancer cell lines and narrowed the shortest region of overlap to approximately 2 Mb. Based on statistical analysis of copy number increase and overexpression, the 9p24 amplicon contains six candidate oncogenes. Among these, four genes (GASC1 UHRF2, KIAA1432 and C9orf123) are overexpressed only in the context of gene amplification while two genes (ERMP1 and IL33) are overexpressed independent of the copy number increase. We then focused our studies on the UHRF2 gene, which has a potential involvement in both DNA methylation and histone modification. Knocking down UHRF2 expression inhibited the growth of breast cancer cells specifically with 9p24 amplification. Conversely, ectopic overexpression of UHRF2 in non-tumorigenic MCF10A cells promoted cell proliferation. Furthermore, we demonstrated that UHRF2 has the ability to suppress the expression of key cell-cycle inhibitors, such as p16(INK4a), p21(Waf1/Cip1) and p27(Kip1). Taken together, our studies support the notion that the 9p24 amplicon contains multiple oncogenes that may integrate genetic and epigenetic codes and have important roles in human tumorigenesis.

Racial differences in colorectal cancer incidence and mortality in the Women's Health Initiative

BACKGROUND

Colorectal cancer (CRC) incidence and mortality rates are higher in African-Americans as compared with other racial/ethnic groups. The women's health initiative (WHI) study sample was used to determine whether differences in CRC risk factors explain racial/ethnic differences in incidence and mortality.

METHODS

The WHI is a longitudinal study of postmenopausal women recruited from 40 centers. Baseline questionnaires were used to collect sociodemographic and health status information. All CRC diagnoses were centrally adjudicated. Cox regression models were used to compute hazard ratios (HRs) and 95% confidence intervals (CIs) for invasive CRC by race/ethnicity.

RESULTS

The study sample included 131,481 (83.7%) White, 14,323 (9.1%) African-American, 6,362 (4.1%) Hispanic, 694 (0.4%) Native American and 4,148 (2.6%) Asian/Pacific Islanders. After a mean follow-up of 10.8 years (SD 2.9), CRC incidence was the highest in African-Americans (annualized rate = 0.14%), followed by Whites and Native Americans (0.12% each), Asian/Pacific Islanders (0.10%), and Hispanics (0.08%). After adjustment for age and trial assignment, Hispanics had a lower risk compared with Whites, HR 0.73 (95% CI: 0.54-0.97) (P = 0.03), and African-Americans had a marginally greater risk, HR 1.16 (95% CI: 0.99-1.34), P = 0.06. Multivariable adjustment attenuated the difference in incidence between African-Americans and Whites (HR 0.99, 95% CI: 0.82-1.20), while strengthening the lower HR for Hispanics (HR 0.68, 95% CI: 0.48-0.97).

CONCLUSIONS

African-American/White differences in CRC risk are likely due to sociodemographic/cultural factors other than race.

IMPACT

A number of modifiable exposures could be a focus for reducing CRC risk in African-Americans.

Social network and health outcomes among African American cardiac rehabilitation patients

OBJECTIVE

We tested the hypotheses that the number of close social network members and the health-related support provided by social network members are predictive of coping efficacy and health behaviors.

METHODS

Cross-sectional data were collected from 115 African Americans enrolled in cardiac rehabilitation. Measures included the social convoy model, SF-36, the Social Interaction Questionnaire, the Patient Self-Efficacy Questionnaire, and an investigator-developed assessment of health behaviors.

RESULTS

Bivariate relationships were found between the number of inner network members and coping efficacy (r = .19, P < .05) and health behaviors (r = .18, P < .06), and between health-related support and coping efficacy (r = .22, P < .05) and health behaviors (r = .28, P < .001). Regression analyses support the hypothesis that close network members predicted better coping efficacy (β = .18, P < .05) and health behaviors (β = .19, P < .05). Health-related support also predicted coping efficacy (β = .23, P < .05) and health behaviors (β = .30, P < .01).

CONCLUSION

African Americans with larger inner networks have more health support, better health behaviors, and higher coping efficacy. The number of close social network members and related health-support promote health through health behaviors and coping efficacy.

Abstract 1922: Ethnic and racial differences in colorectal cancer

Introduction: The Women's Health Initiative (WHI) provides a robust database to determine whether differences in known colorectal cancer (CRC) risk factors influence ethnic and racial differences in incidence and mortality. Methods: The WHI is a multi-center longitudinal study of postmenopausal women age 50-79 years recruited from 40 centers across the US. Baseline self-administered questionnaires were used to collect self-identified ethnicity or race, other demographics and health status. Cancer screening information was collected annually and cancer diagnoses were centrally adjudicated. Cox proportional hazards regression was used to compute hazard ratios (HRs) and 95% confidence intervals (CIs) for invasive CRC by ethnicity/race. Results: The ethnic and racial composition of the sample is 131,481 (84%) White, 14,323 (9%) African American (AA), 6,362 (4%) Hispanic, 694 (&lt;1%) Native American and 4,148 (3%) Asian/Pacific Islander (API). After a mean follow-up of 10.8 years (SD 2.9), CRC incidence was highest among AA (annualized percent 0.14%), followed by Whites and Native Americans (0.12% each), API (0.10%) and Hispanics (0.08%). After adjustment for age and cohort assignment, Hispanics had a lower risk of CRC compared to Whites, HR 0.73 (95% CI: 0.54-0.97) (p=0.03), and AA had a marginally greater risk, HR 1.16 (95% CI: 0.99-1.34), p=0.06. Adjustment for other covariates, eliminated the difference in incidence between AA and Whites (HR 0.99, 95% CI: 0.82-1.20), however the difference in incidence between Hispanics and Whites increased (HR 0.68, 95% CI: 0.48-0.97), p = 0.03. Conclusions: Differences in CRC risk between Hispanics and Whites are not explained by sociodemographic or behavioral factors in the WHI cohort.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1922. doi:10.1158/1538-7445.AM2011-1922

Abstract 4700: Identification and functional analysis of 9p23-24 amplified genes in human breast cancer

Gene amplification is a major mechanism used by cancer cells to increase gene expression and subsequently gain a growth and survival advantage. Previously, we identified a novel amplicon at 9p23-24 region in human esophageal and breast cancer and originally cloned a novel gene GASC1 (Gene Amplified in Squamous Cell Carcinoma 1) from this amplicon. Accumulating evidence suggests common amplicons that occur in breast and other cancers contain multiple oncogenes that could play a role in cancer initiation and progression. In the current study, we aimed to comprehensively characterize the 9p23-24 amplified genes in human breast cancer. We performed array CGH analysis on a panel of cancer cell lines with the Agilent 244K microarray chip and narrowed the shortest region of overlapping (SRO) of the 9p23-24 amplicon to ∼2 Mb. Eleven genes within the SRO regions were examined for their mRNA expression by quantitative RT-PCR (qRT-PCR). Based on statistical association between copy number and expression, we confirmed GASC1 as a top candidate oncogene and identified three new potential oncogenes, UHRF2, KIAA1432 and C9orf123. Our more recent studies indicated that GASC1 is a member of a new class of oncogenes that are involved in the deregulation of histone methylation in cancer cells. We found that GASC1 induces the expression of core stemness transcription factors NANOG, SOX2 and OCT4, as well as classical oncogenes, including NOTCH1 and MYC, in breast cancer cells. On the other hand, UHRF2 encodes a nuclear protein that is involved in cell-cycle regulation. Knocking down UHRF2 slowed cell growth and inhibited colony formation of 9p23-24 amplified breast cancer cells. Furthermore, we demonstrated that expression levels of key tumor suppressing genes, including p16/INK4a, p21/WAF1 and p27/KIP1, were increased after knocking down UHRF2 in breast cancer cells. Collectively, our studies support the notion that the 9p23-24 amplicon contains multiple candidate oncogenes and may play an important role in human tumorigenesis.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4700. doi:10.1158/1538-7445.AM2011-4700

Engineering a waste management enzyme to overcome cancer resistance to apoptosis: adding DNase1 to the anti-cancer toolbox

Cancer treatment is often complicated by resistance to conventional anti-cancer treatment and to more recently developed immunotherapy and gene therapy. These therapeutic modalities aim at activating death pathways within cancer cells. Attempts to activate the apoptotic death pathway, by overexpressing proapoptotic signals, are compromised by cancer defense mechanisms, which disrupt the apoptotic-signaling cascade downstream of the overexpressed component. Here, we describe a therapeutic option of triggering apoptosis without activating the apoptotic-signaling cascade or using the native apoptosis executioner nuclease. We have engineered Deoxyribonuclease-1 (DNase1), a waste-management enzyme, by deleting its signal peptide, adding a nuclear localization signal, and mutating its actin-binding site. Apoptosis studies and colony-forming assay for assessing cell viability were conducted in apoptosis-resistant Mel-Juso human melanoma cells. The modified DNase1 reduced cell viability by 77% relative to controls. It also induced typical microscopic features of cellular apoptosis, such as Terminal Transferase dUTP Nick-End Labeling-positive cells and DNA fragmentation. Quantification of apoptosis by Laser scanning cytometry demonstrated high-killing efficiency of 70-100%. The results suggest that this modified DNase1 can efficiently eliminate apoptosis-resistant cancer cells through apoptosis. Coupled to different tissue-specific gene expression elements, this recombinant DNase1 may serve as a platform for eliminating a variety of cancer types.

Outcome of patients with early breast cancer receiving nitrogen-containing bisphosphonates: a comparative analysis from the Metropolitan Detroit Cancer Surveillance System

BACKGROUND

Preclinical data suggest that bisphosphonates exhibit antitumor activity. However, clinical studies indicated conflicting results. In this study, we compared the overall survival (OS) of postmenopausal patients with nonmetastatic invasive breast cancer who received any of the second-generation nitrogen-containing bisphosphonates for osteopenia or osteoporosis, with the survival of those who did not.

PATIENTS AND METHODS

We conducted a retrospective study at the Wayne State University/Karmanos Cancer institute (KCI) in Detroit, Michigan and extracted data from the Metropolitan Detroit Cancer Surveillance System (MDCSS), a Surveillance, Epidemiology and End Results (SEER) registry. Patients > 50 years of age with stage I, II, or III invasive breast cancer between the years 2000 through 2003 were included. Information regarding medications was extracted from the patients' medical records.

RESULTS

A total of 696 women with stage I-III breast cancer were included. Ninety-seven women (14%) used nitrogen-containing bisphosphonates. The difference in OS between bisphosphonate users and nonusers was not statistically significant (P = .32) at 3 years. After adjusting for differences between the groups in age, stage of disease, hormone receptor status, endocrine therapy, vitamin D, and calcium use, there was a marginally significant (P = .07) difference in survival; bisphosphonate users had poorer survival than nonusers.

CONCLUSION

Our results indicate that the use of nitrogen-containing bisphosphonates is not associated with improved OS in patients with nonmetastatic breast cancer, even after adjusting for known prognostic factors, but with a marginally worse OS. Further research is awaited to clarify the role of bisphosphonates in the adjuvant setting.

A novel signaling axis of matriptase/PDGF-D/ß-PDGFR in human prostate cancer

Increasing evidence indicates the significance of platelet-derived growth factor receptor-β (β-PDGFR) signaling in prostate cancer (PCa). Accordingly, preclinical studies suggest the potential of β-PDGFR as a therapeutic target in metastatic PCa. However, a ligand responsible for β-PDGFR activation in PCa was unknown, and recent clinical trials with imatinib mesylate showed limited success due to normal tissue toxicity. Similarly, in spite of mounting evidence indicating the significance of matriptase in PCa, little is known about its substrates or molecular actions during PCa progression. Here, we identified PDGF-D as a ligand for β-PDGFR in PCa and discovered matriptase as its regulator. Matriptase activates PDGF-D by proteolytic removal of the CUB domain in a 2-step process, creating a hemidimer, followed by growth factor domain dimer (GFD-D) generation. Matriptase can deactivate PDGF-D by further proteolytic cleavage within the GFD, revealing its biphasic regulation. Importantly, PDGF-D/matriptase colocalization is accompanied with β-PDGFR phosphorylation in human PCa tissues. This study unveiled a novel signaling axis of matriptase/PDGF-D/β-PDGFR in PCa, providing new insights into functional interplay between serine protease and growth factor signaling networks.

Differential effects of thin and thick filament disruption on zebrafish smooth muscle regulatory proteins

BACKGROUND

 The smooth muscle actin binding proteins Caldesmon and Tropomyosin (Tm) promote thin filament assembly by stabilizing actin polymerization, however, whether filament assembly affects either the stability or activation of these and other smooth muscle regulatory proteins is not known.

METHODS

Measurement of smooth muscle regulatory protein levels in wild type zebrafish larvae following antisense knockdown of smooth muscle actin (Acta2) and myosin heavy chain (Myh11) proteins, and in colourless mutants that lack enteric nerves. Comparison of intestinal peristalsis in wild type and colourless larvae.

KEY RESULTS

Knockdown of Acta2 led to reduced levels of phospho-Caldesmon and Tm. Total Caldesmon and phospho-myosin light chain (p-Mlc) levels were unaffected. Knockdown of Myh11 had no effect on the levels of either of these proteins. Phospho-Caldesmon and p-Mlc levels were markedly reduced in colourless mutants that have intestinal motility comparable with wild type larvae.

CONCLUSIONS & INFERENCES

These in vivo findings provide new information regarding the activation and stability of smooth muscle regulatory proteins in zebrafish larvae and their role in intestinal peristalsis in this model organism.

Glycemic index, glycemic load, and the risk of pancreatic cancer among postmenopausal women in the women's health initiative observational study and clinical trial

BACKGROUND

Several reports have suggested that conditions associated with hyperinsulinemia and insulin resistance, such as diets high in carbohydrates, may influence the risk of pancreatic cancer, although results from prior studies have been mixed.

METHODS

We utilized data from the population-based women's health initiative (WHI) cohort to determine whether dietary factors that are associated with increased postprandial blood glucose levels are also associated with an increased risk of pancreatic cancer. The WHI included 161,809 postmenopausal women of ages 50-79, in which 332 cases of pancreatic cancer were identified over a median of 8 years of follow-up; 287 of these cases met the criteria for analysis. A validated 122-item food frequency questionnaire was used to estimate dietary glycemic load (GL), glycemic index (GI), total and available carbohydrates, fructose and sucrose. Baseline questionnaires and physical exams provided information on demographic, medical, lifestyle, and anthropometric characteristics. Cox proportional hazards models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for the association between the exposures of interest and pancreatic cancer risk, with adjustment for potential confounders.

RESULTS

Dietary GL, GI, carbohydrates, fructose, and sucrose were not associated with increased risk of pancreatic cancer. The multivariable adjusted HR for the highest vs. the lowest quartile of GL was 0.80 (95% CI = 0.55-1.15, trend p = 0.31) and 1.13 (95% CI = 0.78-1.63, trend p = 0.94) for GI. The results remained negative when individuals with a history of diabetes were excluded.

CONCLUSIONS

Our results do not support the hypothesis that dietary intake of carbohydrates is associated with increased risk of pancreatic cancer.

Long term follow-up of allogeneic stem cell transplantation in patients with myelodysplastic syndromes using busulfan, cytosine arabinoside, and cyclophosphamide

We report here the 10-year follow-up of 86 patients who underwent allogeneic stem cell transplantation (ASCT) for myelodysplastic syndrome (MDS). All patients received the busulfan, cytosine arabinoside, and cyclophosphamide (BAC) preparative regimen which consisted of busulfan 16 mg/kg, cytosine arabinoside 8 g/m(2) IV, and cyclophosphamide 120 mg/kg IV. Fifty-nine patients (69%) had de novo MDS; 26 (30%) had secondary MDS (treatment related), and one had a preceding aplastic anemia which progressed to MDS before transplant. Cytogenetics (80 patients) was classified as good (34%), intermediate (17%), or poor (42%). With a median follow-up for survivors of 124 months, the 10-year Kaplan-Meier estimates for overall survival (OS) was 43% (95% confidence interval [CI]: 31-53%). Cumulative nonrelapse mortality (NRM) and relapse was 43% (95% CI: 32-54%) and 19% (95% CI: 11-27%), respectively. No patient relapsed after 2 years. In patients with RAEB-T/AML, 10-year relapse-free survival (RFS), relapse, and NRM was 36%, 36%, and 27%, respectively. Younger age (P = 0.05), human leukocyte antigen (HLA) match (P = 0.002), good risk cytogenetics (P = 0.008), and having a related donor (P = 0.03) significantly improved overall and RFS in the multivariable analysis. The long-term follow-up of patients receiving the BAC regimen with ASCT in this study indicated durable relapse-free and OS with acceptable toxicity in this group of patients with high-risk features.

[S1 guideline on the "diagnosis and treatment of snoring in adults"]

Due to the frequency of this phenomenon and the often considerable distress caused to the affected person, competent advice, diagnosis and treatment of snoring in adults is of particular importance. The aim of this guideline is to promote high-quality medical care for patients affected by this problem. According to the three-level concept of the AWMF, it corresponds to an S1 guideline. Prior to any therapeutic intervention, relevant sleep medical history, clinical examination, as well as a mandatory objective diagnostic measure are performed. Snoring is only treated if the patient asks for it. In general, invasive methods should be viewed critically and the patient should be advised correspondingly. In the case of surgical therapy, minimally invasive techniques are preferred. Reducing body weight (in the case of overweight snorers), abstinence from alcohol, nicotine and sleep medication, as well as maintaining a healthy sleep-wake cycle can be recommended from a sleep-medicine perspective, although convincing clinical studies are not yet available. Since evidence for the effectiveness of muscle stimulation or various methods for toning and training of the muscles of the floor of mouth is not available, these methods are not recommended. Snoring can be successfully treated with the use of an intraoral device; however, careful patient selection is important. Avoiding a supine position during sleep can be helpful in some cases. Only limited data is available on the success rates of the surgical approaches and long term data is often lacking, and not all techniques have been sufficiently evaluated from a scientific point of view. Nasal surgery is only indicated if the patient suffers from nasal obstruction. Extensive data supports the effectiveness of laser-assisted resection of excessive soft palate tissue (laser-assisted uvuloplasty, LAUP). In principle, however, such resections can be performed using other techniques. Placebo-controlled studies were able to prove the effectiveness of radiofrequency surgery of the soft palate. A reduction in snoring could also be achieved in many cases by means of soft palate implants with minimal post-operative morbidity. The indication for tonsillectomy and uvulopalatopharyngoplasty should be made cautiously due to the comparatively high morbidity associated with these procedures.

Analysis of citations to biomedical articles affected by scientific misconduct

We describe the ongoing citations to biomedical articles affected by scientific misconduct, and characterize the papers that cite these affected articles. The citations to 102 articles named in official findings of scientific misconduct during the period of 1993 and 2001 were identified through the Institute for Scientific Information Web of Science database. Using a stratified random sampling strategy, we performed a content analysis of 603 of the 5,393 citing papers to identify indications of awareness that the cited articles affected by scientific misconduct had validity issues, and to examine how the citing papers referred to the affected articles. Fewer than 5% of citing papers indicated any awareness that the cited article was retracted or named in a finding of misconduct. We also tested the hypothesis that affected articles would have fewer citations than a comparison sample; this was not supported. Most articles affected by misconduct were published in basic science journals, and we found little cause for concern that such articles may have affected clinical equipoise or clinical care.

Analysis of the expression of human tumor antigens in ovarian cancer tissues

Biomarkers for early detection of cancer have great clinical diagnostic potential. Numerous reports have documented the generation of humoral immune responses that are triggered in response to changes in protein expression patterns in tumor tissues and these biomarkers are referred to as tumor associated antigens (TAAs). Using a high-throughput technology, we previously identified 65 proteins as diagnostically useful TAAs by profiling the humoral immune responses in ovarian cancer (OVCA) patients. Here we determined the expression status of some of those TAAs in tissues from OVCA patients. The protein expression patterns of 4 of those 65 antigens, namely NASP, RCAS1, Nijmegen breakage syndrome1 (NBS1) and eIF5A, along with p53 and Her2 (known molecular prognosticators) and two proteins that interact with NBS1, MRE11 and RAD50, were assessed by immunohistochemistry (IHC). NASP and RCAS1 proteins were more frequently expressed in ovarian cancer tissues than with normal ovarian tissue and serous cystadenomas and MRE11 was less frequently expressed. When evaluated simultaneously, only NASP and MRE11 remained statistically significant with sensitivity of 66% and specificity of 89%. None of these proteins' expression levels were prognostic for survival. Together, our results indicate that occurrence of humoral immune responses against some of these TAAs in OVCA patients is triggered by antigen protein overexpression.

Autoantibodies in Breast Cancer Identify Proteins Involved in Self- Renewal and Epigenetic Chromatin Remodeling

Recent studies have shown that autoantibodies developing in cancer patients are tumor-associated and are promising biomarkers for the diagnosis and prognosis of cancer. Here we report a panel of signal transduction molecules with partial sequences identical to the oncogene Bmi-1, NIFK, a nucleolar protein interacting with the FHA domain of Ki- 67, TAB182, a protein interacting with tankyrase-1, CNOT6L, a subunit of the CCR4-NOT complex and to Elp3, a subunit of the elongator complex that are recognized as autoantigens by breast cancer sera with the ability to discriminate between invasive breast cancer and normal sera with high sensitivity and specificity. The proteins bearing the epitopes recognized by these antibodies have conserved regions involved in protein-protein interactions participating in regulatory processes such as self renewal, cell proliferation and survival, chromatin modulation, transcriptional silencing and organ patterning, usually ascribed to stem cell function. In this work we demonstrate by autoantigen microarray analysis that autoantibodies in breast cancer sera have the potential to delineate pathway connectivity. Our data indicate that several pathways involved in maintaining telomere stability are the target of an autoimmune reaction in breast cancer. These findings suggest that autoantibodies with the ability to recognize autoantigens involved in self-renewal and epigenetic chromatin remodeling have the potential to predict an invasive tendency of breast cancer.

Phase II Study of PEND Chemotherapy in Patients with Refractory/Relapsed Hodgkin Lymphoma

High-dose chemotherapy with autologous marrow or stem cell rescue (HDC/ASCT) is an effective strategy in patients with relapsed Hodgkin lymphoma. Various chemotherapy regimens have been used for cytoreduction prior to HDC/ASCT. In this study, our objective was to determine the response rate to PEND in a group of patients with relapsed Hodgkin lymphoma. Nineteen patients with relapsed or primary refractory Hodgkin lymphoma underwent treatment with the PEND regimen and received a median of 2 cycles (1 - 6 cycles). The PEND regimen builds on our prior results with ABDIC and consists of prednisone 40 mg/m2 orally (PO) daily x 5 days; etoposide 50 mg/m2 PO daily x 14 days; mitoxantrone 5 mg/m2/d IV, days 1 and 3; and DTIC 200 mg/m2/d intravenous continuous infusion (CIV) over 24 h, days 1 to 5, via central venous catheter. The treatment was given every 28 days. There were 3 complete responses (16%) and 10 partial responses (53%) yielding a total response rate of 69% (95% C.I. 43%, 87%). Myelosuppression was the predominant toxicity; no deaths were due to toxicity. After achieving maximum response to PEND, 10 eligible patients received a consolidative treatment with HDC/ASCT. All 6 patients who did not respond to PEND died from disease progression whereas 5 of 13 responders were alive after 10 years of follow-up (3 without disease). There were 11 deaths due to disease progression; three from other causes. The initial response to PEND before subsequent ASCT consolidation treatment appears to be associated with survival. All patients who failed to achieve a response have died. We conclude that PEND is an effective treatment strategy in Hodgkin lymphoma patients previously treated with both ABVD and MOPP.

WT1 marker is not sufficient for distinguishing between melanoma and melanocytic nevi

BACKGROUND

The heterogeneous histological features of melanoma may often overlap with melanocytic nevi. For this reason, pathologists have sought after immunohistochemistry to assist with difficult cases. Recently, Wilms' tumor 1 protein (WT1) has been suggested to differentiate between melanoma and melanocytic nevi.

OBJECTIVE

Our objective was to determine whether immunohistochemistry analysis of WT1 expression is a reliable tool in differentiating cutaneous melanoma from melanocytic nevi.

METHODS

Forty-five melanoma and 43 melanocytic nevi were immunostained with anti-WT1 monoclonal antibody (clone 6F-H2).

RESULTS

Forty of the 45 cutaneous melanoma (89%) and 22 of the 43 melanocytic nevi (51%) stained (> 10% cells) for WT1. The highest sensitivity for WT1 was expressed by nodular melanoma (19/20), superficial spreading melanoma (8/10) and Spitz nevi (9/11). At the threshold of above 75% WT1-stained cells, the specificity for melanoma was 95% but the sensitivity was only 31%. At the threshold of 10%, the sensitivity increased to 89% but the specificity decreased to only 49%. Finally, at the threshold of 25% and 50%, the sensitivity and specificity were 71%, 61% and 64%, 77%, respectively.

CONCLUSIONS

Our data suggest that melanoma is associated with increased WT1 expression. However, as a single immunostaining marker, WT1 is not sufficient for distinguishing melanoma from melanocytic nevi.

Cytokine and cytokine receptor single-nucleotide polymorphisms predict risk for non-small cell lung cancer among women

Studies on the relationships between inflammatory pathway genes and lung cancer risk have not included African-Americans and have only included a handful of genes. In a population-based case-control study on 198 African-American and 744 Caucasian women, we examined the association between 70 cytokine and cytokine receptor single-nucleotide polymorphisms (SNPs) and risk of non-small cell lung cancer (NSCLC). Unconditional logistic regression was used to estimate odds ratios and 95% confidence intervals in a dominant model adjusting for major risk factors for lung cancer. Separate analyses were conducted by race and by smoking history and history of chronic obstructive pulmonary disease among Caucasians. Random forest analysis was conducted by race. On logistic regression analysis, IL6 (interleukin 6), IL7R, IL15, TNF (tumor necrosis factor), and IL10 SNP were associated with risk of non-small cell lung cancer among African-Americans; IL7R and IL10 SNPs were also associated with risk of lung cancer among Caucasians. Although random forest analysis showed IL7R and IL10 SNPs as being associated with risk for lung cancer among African-Americans, it also identified TNFRSF10A SNP as an important predictor. On random forest analysis, an IL1A SNP was identified as an important predictor of lung cancer among Caucasian women. Inflammatory SNPs differentially predicted risk for NSCLC according to race, as well as based on smoking history and history of chronic obstructive pulmonary disease among Caucasian women. Pathway analysis results are presented. Inflammatory pathway genotypes may serve to define a high risk group; further exploration of these genes in minority populations is warranted.

Utility of DNA postreplication repair protein Rad6B in neoadjuvant chemotherapy response

Neoadjuvant chemotherapy is a standard therapy for patients with locally advanced breast cancer (LABC) and is increasingly used for early stage operable breast cancer. Not all patients benefit from it, and reliable markers for predicting response are needed. The cytotoxic effects of chemotherapy are mediated by induction of DNA damage in tumor cells. There is evidence that resistance to chemotherapy is related to enhanced repair of DNA lesions. The postreplication DNA repair (PRR) or translesion synthesis backup DNA repair pathway is critical for cell viability, conferring tolerance to DNA damaging drugs, and maintenance of genomic integrity. However, despite its importance in conferring tolerance to a variety of DNA damaging drugs including cytotoxic chemotherapy, the involvement of this backup repair pathway in chemotherapy response has not been studied. The Rad6B protein is a fundamental component of PRR. We have shown previously that the ability of breast cells to tolerate chemotherapeutic drugs correlates with Rad6B expression levels and PRR capacity. To determine whether Rad6B expression/distribution can be used singly or in combination with p53, Mdr-1/PgP, PCNA or beta-catenin as predictors of response to neoadjuvant chemotherapy, we analyzed posttreatment samples from 20 patients with LABC in a retrospective study. Only preferential Rad6B nuclear localization was associated with response to neoadjuvant chemotherapy. Nuclear exclusion with cytoplasmic overexpression of Rad6B was observed in some patients who failed to respond, but the association with response is not statistically significant. This is the first study to report that the postreplication DNA repair protein Rad6B could be used as an independent marker for determining response to neoadjuvant chemotherapy. This is an exploratory study and larger studies utilizing interim evaluations of Rad6B expression, its subcellular localization and repair activity are required to confirm its utility as a predictor of chemotherapeutic response.

Homocysteine: a new cardiac risk factor?

Elevated plasma homocysteine levels have recently been implicated as a new risk factor for coronary artery disease. In this article, homocysteine metabolism, secondary causes of elevated plasma homocysteine, and the potential mechanism of vascular damage in hyperhomocysteinemia are briefly reviewed. The current clinical evidence implicating hyperhomocysteinemia as a risk factor for coronary artery disease, as well as the data regarding the effects of B vitamin supplementation on homocysteine concentrations, are also reviewed. The current recommendation of the authors is to treat patients with known coronary artery disease or those who are considered to be at high risk for coronary artery disease with 400 microg of folate supplementation. Until prospective clinical trial data become available, this approach appears to be a safe and effective way to approach this patient population.

Hormones and the cardiologist

Cardiologists must become more involved in discussing and recommending hormone replacement in post-menopausal women with established coronary artery disease, and those individuals at high risk of coronary events. A large amount of epidemiologic and observational data, as well as new research in vascular biology, strongly support the benefits of estrogen on the development and progression of coronary atherosclerosis. While breast and uterine cancer are valid concerns, selected high-risk women with and without established coronary disease should be counseled by an informed cardiologist to consider hormone replacement therapy.

Racial disparity in breast cancer and functional germ line mutation in galectin-3 (rs4644): a pilot study

For reasons largely unknown, Caucasian women are at a significantly higher risk of developing breast cancer than Asian women. Over a decade ago, mutations in BRCA1/2 were identified as genetic risk factors; however, the discovery of additional breast cancer genes and genes contributing to racial disparities are lacking. We report a functional germline mutation (polymorphism) in the galectin-3 gene at position 191 (rs4644) substituting proline with histidine (P64H), which results in susceptibility to matrix metalloproteinase cleavage and acquisition of resistance to drug-induced apoptosis. This substitution correlates with incidence of breast cancer and racial disparity. Genotype analysis of 338 Caucasian (194 disease free and 144 breast cancer patients) and 140 Asian (79 disease free and 61 breast cancer patients) women showed that the allele homozygous for H64 exists in disease free Caucasian and Asian women at a frequency of 12% and 5%, respectively, versus 37% and 82% in breast cancer patients. The data indicate that H/H allele is associated with increased breast cancer risk in both races. The data implicate galectin-3 H(64) in breast cancer and explain, in part, the noted racial disparity, thus providing a novel target for diagnosis and treatment.

Challenges for multilevel health disparities research in a transdisciplinary environment

Numerous factors play a part in health disparities. Although health disparities are manifested at the level of the individual, other contexts should be considered when investigating the associations of disparities with clinical outcomes. These contexts include families, neighborhoods, social organizations, and healthcare facilities. This paper reports on health disparities research as a multilevel research domain from the perspective of a large national initiative. The Centers for Population Health and Health Disparities (CPHHD) program was established by the NIH to examine the highly dimensional, complex nature of disparities and their effects on health. Because of its inherently transdisciplinary nature, the CPHHD program provides a unique environment in which to perform multilevel health disparities research. During the course of the program, the CPHHD centers have experienced challenges specific to this type of research. The challenges were categorized along three axes: sources of subjects and data, data characteristics, and multilevel analysis and interpretation. The CPHHDs collectively offer a unique example of how these challenges are met; just as importantly, they reveal a broad range of issues that health disparities researchers should consider as they pursue transdisciplinary investigations in this domain, particularly in the context of a large team science initiative.

Is adjuvant therapy necessary for Stage IA and IB uterine papillary serous carcinoma and clear cell carcinoma after surgical staging?

Adjuvant therapy of early-stage uterine papillary serous carcinoma (UPSC) and clear cell carcinoma (CCC) is controversial. We conducted a prospective cohort study to evaluate outcomes of patients with early-stage UPSC or CCC who were followed without adjuvant therapy after complete surgical staging. From 2000 to 2006, we evaluated all consecutive patients with stage IA/IB UPSC or CCC who had surgical staging by a gynecological oncologist at the London Health Sciences Centre, Canada. Follow-up consisted of history and physical examination every 3 months for 2 years, then every 6 months for the next 3 years. Primary outcome measure was 2-year disease-free survival. There were 22 evaluable patients. Mean patient age was 63.4 years. Median number of pelvic and para-aortic lymph nodes resected was 15 (range 2-39) and 4 (range 0-12), respectively. Thirteen had UPSC, seven had CCC, and two had both UPSC and CCC. Nine had stage IA and 13 had stage IB disease. Median follow-up was 25 months (range 6-72). Only one patient has recurred (stage IB UPSC, isolated vault recurrence 10 months after surgery), but she is well 9 months after receiving pelvic radiotherapy and vault brachytherapy. Two-year disease-free survival was 95%. These results suggest that adjuvant therapy may not be necessary for stage IA and IB UPSC and CCC after surgical staging. Further prospective evaluation of different adjuvant therapy practices is required for early-stage UPSC and CCC, which may be useful in the design of future clinical trials.

Autoantibody approach for serum-based detection of head and neck cancer

Currently, no effective tool exists for screening or early diagnosis of head and neck squamous cell carcinoma (HNSCC). Here, we describe an approach for cancer detection based on analysis of patterns of serum immunoreactivity against a panel of biomarkers selected using microarray-based serologic profiling and specialized bioinformatics. We biopanned phage display libraries derived from three different HNSCC tissues to generate 5,133 selectively cloned tumor antigens. Based on their differential immunoreactivity on protein microarrays against serum immunoglobulins from 39 cancer and 41 control patients, we reduced the number of clones to 1,021. The performance of a neural network model (Multilayer Perceptron) for cancer classification on a data set of 80 HNSCC and 78 control samples was assessed using 10-fold cross-validation repeated 100 times. A panel of 130 clones was found to be adequate for building a classifier with sufficient sensitivity and specificity. Using these 130 markers on a completely new and independent set of 80 samples, an accuracy of 84.9% with sensitivity of 79.8% and specificity of 90.1% was achieved. Similar performance was achieved by reshuffling of the data set and by using other classification models. The performance of this classification approach represents a significant improvement over current diagnostic accuracy (sensitivity of 37% to 46% and specificity of 24%) in the primary care setting. The results shown here are promising and show the potential use of this approach toward eventual development of diagnostic assay with sufficient sensitivity and specificity suitable for detection of early-stage HNSCC in high-risk populations.

Mutations in SIRT2 deacetylase which regulate enzymatic activity but not its interaction with HDAC6 and tubulin

Human SIRT2 is a cytoplasmic NAD-dependent deacetylase implicated in the mitotic regulation of microtubule dynamics by its association with the class II histone deacetylase 6 (HDAC6). We have previously reported that SIRT2 is multiply phosphorylated in a cell cycle dependent pattern. Here, we demonstrate that HDAC6 binds to both phosphorylated and unphosphorylated forms of SIRT2 and that tubulin binds only to the SIRT2-HDAC6 complex. Tubulin does not bind to either HDAC6 or SIRT2 individually. In addition, we show that replacement of specific serines with alanines in either isoform of SIRT2 regulates its enzymatic activity. We also found that overexpression of isoform2 was deleterious to cell survival. SIRT2 was found to be phosphorylated at serines 368 and 372, outside the conserved core domain of the Sir2 protein family. Double replacement of S368A and S372A reduced SIRT2 deacetylase activity by 44% compared to wildtype activity. Replacements of other serine, threonine, and tyrosine residues, which did not alter the phosphorylation pattern, had varying effects on SIRT2 deacetylase activity but no effect on tubulin/HDAC6 binding.

Multianalyte tests for the early detection of cancer: speedbumps and barriers

It has become very clear that a single molecular event is inadequate to accurately predict the biology (or pathophysiology) of cancer. Furthermore, using any single molecular event as a biomarker for the early detection of malignancy may not comprehensively identify the majority of individuals with that disease. Therefore, the fact that technologies have arisen that can simultaneously detect several, possibly hundreds, of biomarkers has propelled the field towards the development of multianalyte-based in vitro diagnostic early detection tests for cancer using body fluids such as serum, plasma, sputum, saliva, or urine. These multianalyte tests may be based on the detection of serum autoantibodies to tumor antigens, the presence of cancer-related proteins in serum, or the presence of tumor-specific genomic changes that appear in plasma as free DNA. The implementation of non-invasive diagnostic approaches to detect early stage cancer may provide the physician with evidence of cancer, but the question arises as to how the information will affect the pathway of clinical intervention. The confirmation of a positive result from an in vitro diagnostic cancer test may involve relatively invasive procedures to establish a true cancer diagnosis. If in vitro diagnostic tests are proven to be both specific, i.e. rarely produce false positive results due to unrelated conditions, and sufficiently sensitive, i.e. rarely produce false negative results, then such screening tests offer the potential for early detection and personalized therapeutics using multiple disease-related targets with convenient and non-invasive means. Here we discuss the technical and regulatory barriers inherent in development of clinical multianalyte biomarker assays.

Soy isoflavones enhance radiotherapy in a metastatic prostate cancer model

We previously reported that genistein, the bioactive isoflavone of soybeans, acts as a radiosensitizer for prostate cancer. Pretreatment of tumor cells with genistein potentiated radiation-induced killing in vitro and in orthotopic models in vivo. However, pure genistein promoted increased lymph node metastasis, when administered alone in vivo. We investigated in vitro and in vivo the effects of soy isoflavones (genistein, daidzein and glycitein) as soy pills of similar composition are used in human interventions but not pure genistein. Soy isoflavones inhibited cell survival and potentiated radiation cell killing in PC-3 tumor cells, in vitro. Increased cell killing correlated with inhibition of antiapoptotic molecules Bcl-xL and survivin, upregulation of proapoptotic Bax molecule and PARP cleavage, suggesting activation of apoptotic pathways. In vivo, using the PC-3 orthotopic metastatic mouse model, soy isoflavones and prostate tumor irradiation led to enhanced control of primary tumor growth and metastasis, as observed with pure genistein and radiation. Interestingly, treatment with soy isoflavones did not increase metastasis to para-aortic lymph nodes in contrast to the consistent increase caused by pure genistein. Histologically prostate tumors, treated with soy isoflavones and radiation, showed tumor destruction and in situ tissue alterations, comparable with genistein and radiation effects. However, genistein, but not soy isoflavones, caused induction of HIF1-alpha in prostate tumors, suggesting that induction of hypoxia by pure genistein could contribute to increased metastasis. Our studies demonstrate the safety and potential role of soy isoflavones for enhancing the therapeutic effect of radiotherapy in prostate cancer.