Polygenic risk score as a determinant of risk of keratinocyte cancer in an Australian population-based cohort.

BACKGROUND: Keratinocyte cancer (KC) risk is determined by genetic and environmental factors. Genetic risk can be quantified by polygenic risk scores (PRS), which sum the combined effects of single nucleotide polymorphisms (SNPs). OBJECTIVES: Our objective here was to evaluate the contribution of the summed genetic score to predict the KC risk in the phenotypically well-characterized Nambour population. METHODS: We used PLINK v1.90 to calculate PRS for 432 cases, 566 controls, using 78 genome-wide independent SNPs that are associated with KC risk. We assessed the association between PRS and KC using logistic regression, stratifying the cohort into three risk groups (high 20%, intermediate 60%, low 20%). RESULTS: The fully adjusted model including traditional risk factors (phenotypic and sun exposure-related), showed a significant 50% increase in odds of KC per standard deviation of PRS (odds ratio (OR) = 1.51; 95% confidence interval (CI) = 1.30-1.76, P = 5.75 × 10-8 ). Those in the top 20% PRS had over three times the risk of KC of those in the lowest 20% (OR = 3.45; 95% CI = 2.18-5.50, P = 1.5 × 10-7 ) and higher absolute risk of KC per 100 person-years of 2.96 compared with 1.34. Area under the ROC curve increased from 0.72 to 0.74 on adding PRS to the fully adjusted model. CONCLUSIONS: These results show that PRS can enhance the prediction of KC above traditional risk factors.

MicroRNA expression is associated with human papillomavirus status and prognosis in mucosal head and neck squamous cell carcinomas.

OBJECTIVES: The major cause of mucosal squamous cell carcinomas of the head and neck (HNSCCs) has been attributed to human papillomavirus (HPV) infection. Here we investigate if microRNA expression in HNSCC can be used as a prognostic tool with or without HPV status. MATERIALS AND METHODS: We performed a discovery miRNA microarray (miRBase v.21) profiling of 52 tonsillar SCCs with TaqMan real-time PCR validation of 228 HNSCCs. Patients had a histologically confirmed primary SCC of the oropharynx, oral cavity, hypopharynx or larynx. Logistic regression models were used to estimate the magnitude of the effect of association with clinical factors and miRNAs associated with HPV status. For recurrence and survival analysis, we used unadjusted and multivariable adjusted Cox proportional hazard regression models. RESULTS: Seventeen miRNAs were significantly associated with better prognosis in the discovery phase and were validated in the extended dataset. The best fitting model (AUC = 0.92) for HPV status included age, smoking, and miRNAs: miR-15b, miR-20b, miR-29a, miR-29c, miR-142, miR-146a and miR-205. Using Cox regression model for recurrence, miR-29a was associated with 49% increased risk of recurrence while miR-30e and miR-342 were associated with decreased risk of recurrence with HRs 0.92 (95% CI 0.85-0.99) and 0.84 (95% CI 0.73-0.98), respectively. Our best fitting model for survival included age, gender, alcohol consumption, N stage, recurrence, HPV status, together with miRNAs-20b, 29a, and 342. CONCLUSION: miRNAs show potential to serve as usual biomarkers to predict the clinical course of patients with mucosal HNSCC.

Viral infections and breast cancer - A current perspective.

Sporadic human breast cancer is the most common cancer to afflict women. Since the discovery, decades ago, of the oncogenic mouse mammary tumour virus, there has been significant interest in the potential aetiologic role of infectious agents in sporadic human breast cancer. To address this, many studies have examined the presence of viruses (e.g. papillomaviruses, herpes viruses and retroviruses), endogenous retroviruses and more recently, microbes, as a means of implicating them in the aetiology of human breast cancer. Such studies have generated conflicting experimental and clinical reports of the role of infection in breast cancer. This review evaluates the current evidence for a productive oncogenic viral infection in human breast cancer, with a focus on the integration of sensitive and specific next generation sequencing technologies with pathogen discovery. Collectively, the majority of the recent literature using the more powerful next generation sequencing technologies fail to support an oncogenic viral infection being involved in disease causality in breast cancer. In balance, the weight of the current experimental evidence supports the conclusion that viral infection is unlikely to play a significant role in the aetiology of breast cancer.

Shared and persistent asymptomatic cutaneous human papillomavirus infections in healthy skin.

Cutaneous human papillomavirus (HPV) types are commonly found in normal skin, and some of them have been suspected to play a role in the development of non-melanoma skin cancer. This present study is divided into three sections, the aims of this study were to examine if certain HPV-types persist over time and if HPV-types are shared within families. From the first part of the study, swab samples from foreheads were collected for three longitudinal studies from one family with a newborn baby. Five specific HPV-types were isolated from the family with a newborn, with HPV-5 and FA67 being found at various time points and prevalence rates in all four members of the family. Part 2 consisted of a followed up study from two families with a 6 years interval. Six of the family members were found to have at least one of the HPV-types identified in the family 6 years earlier. Many of the HPV-types identified were shared within the families studied. Part 3 of this study involved weekly samples from four healthy females for 4 months. Among the four healthy individuals, 11%, 65%, and 56% of the weekly samples were HPV-DNA positive with one individual HPV-negative. All specimens were tested for HPV-DNA by PCR using the broad range HPV-type primer pair FAP59/64. The positive samples were HPV-type determined by cloning and sequencing. Specific cutaneous HPV-types persist over long periods of time in healthy skin in most individuals investigated and certain HPVs are shared between family members.

Calmodulin-dependent kinase II mediates T cell receptor/CD3- and phorbol ester-induced activation of IkappaB kinase.

Numerous fundamental biological processes involve the NFkappaB family of transcription factors. The mechanisms by which this family of proteins is regulated are therefore of widespread importance. In most cells, NFkappaB is bound to inhibitory IkappaB proteins and sequestered in the cytoplasm. NFkappaB-inducing signals result in activation of a large multisubunit kinase complex, IKK, which phosphorylates IkappaB. IkappaB is subsequently degraded, releasing NFkappaB, which translocates to the nucleus. We previously reported that inhibitors of the calcium-binding protein calmodulin (CaM) prevent phorbol ester-induced phosphorylation of IkappaB. Here we show that KN93, an inhibitor of CaM-dependent kinases (CaMKs), also inhibits the phosphorylation of IkappaB. The effect of both CaM and CaMK inhibitors on IkappaB phosphorylation is due to the inhibition of the activity of CaMK II because neither drug has any effect when a derivative of CaMK II that is insensitive to these inhibitors is expressed. When CaMK II is inhibited, phorbol ester is no longer able to activate IKK, placing CaMK II in the signaling pathway that leads to IKK activation. CaM and CaMK inhibitors also block T cell receptor/CD3-induced activation but have no effect on the ability of the cytokine tumor necrosis factor alpha or the phosphatase inhibitor calyculin A to induce degradation of IkappaB. Finally we show that expression of a constitutively active CaMK II results in the activation of NFkappaB. The results identify CaMK II as a mediator of IKK activation specifically in response to T cell receptor/CD3 and phorbol ester stimulation.

The ubiquity and impressive genomic diversity of human skin papillomaviruses suggest a commensalic nature of these viruses.

Human papillomaviruses (HPV) are epitheliotropic viruses, with some types suggested to be associated with skin cancer. In this study, swab samples collected from five different sites on the skin of renal transplant recipients, dialysis patients, and age- and sex-matched healthy controls were analyzed for HPV DNA by a newly designed PCR test. Most individuals were found to have asymptomatic HPV infections; more specifically, 94% of the renal transplant patients, 82% of the dialysis patients, and 80% of the healthy controls were positive for HPV DNA. The multiplicity of the HPVs detected was astounding: 20 previously described and 30 putatively new types were identified by cloning and sequencing of 33 samples from 13 individuals. These results demonstrate that normal human skin harbors an array of papillomaviruses, most of them previously unknown.

Calmodulin dependence of NFkappaB activation.

The NFkappaB family of transcription factors is regulated by inhibitory IkappaB proteins. A diversity of stimuli leads to the phosphorylation and subsequent degradation of IkappaB, releasing NFkappaB to act on its target genes. Calmodulin (CaM) is a key regulator of numerous cellular processes and is the predominant intracellular receptor for Ca2+ signals. Here we report that several CaM antagonists inhibit the activation of NFkappaB, and that this is due to the prevention of inducible IkappaB phosphorylation. Our results suggest that CaM is involved in the phosphorylation of IkappaB, a finding that may help in elucidating the mechanism of this critical step of NFkappaB activation.

Substitution of dangerous chemicals--the solution to problems with chemical health hazards in the work environment?

For many years efforts have been made toward the substitution of less toxic chemicals for particularly toxic ones. Substitutions have been made mainly on the basis of the toxic effect of the virgin compound on humans and the environment, a rationale that may be open to question. This study evaluated a number of substitutions made in recent years. To identify effects on the work and external environments, the chemical products were studied in use within a production system. The main observation was that substitution is a very complex process that might have drawbacks as well as beneficial effects, since new problems may arise through the use of new chemicals. In some cases, knowledge about the extent of these new problems is inadequate, since the substitutions are sometimes not well documented. Substitution may result in reduced use or discontinuance of the original toxic substance and may affect the external as well as the workplace environment.

Monitoring of S- and R-tocainide in human plasma after heptafluorobutyrylation, separation on Chirasil-Val and electron-capture detection.

The conditions for the heptafluorobutyrylation of tocainide have been studied. An almost instantaneous reaction was obtained with 0.01% of heptafluorobutyric anhydride in toluene at 40 degrees C. Higher anhydride concentration caused degradation of the initially formed derivative, mainly by the loss of water, as shown by mass spectral analysis. Tocainide was isolated from plasma by extraction into dichloromethane at alkaline pH. Gas chromatographic separation was performed with a fused-silica capillary column coated with a methyl silicone gum. The enantiomers were separated on a glass capillary column coated with Chirasil-Val. Upon analysing 0.1 ml of plasma eight times the precision was 4.7% at the 10 mumol/1 level for the S-form of tocainide.