Testosterone replacement therapy: association with mortality in high-risk patient subgroups.

OBJECTIVES: We describe studies determining the association between testosterone therapy (TTh) and mortality. MATERIALS & METHODS: We used a registry database of 737 men with adult-onset testosterone deficiency defined as presenting with low serum total testosterone (TT) levels ≤12.1 nmol/L and associated symptoms over a near 10-year follow-up. We compared associations between testosterone undecanoate (TU), cardio-metabolic risk factors and mortality using non-parametric statistics followed by separate Cox regression models to determine if any association between TU and morality was independent of age and cardio-metabolic risk factors. Finally, the association between TU and mortality was studied in men stratified by cardio-metabolic risk. RESULTS: During a median follow-up interquartile range (IQR) of 114 (84-132) months, 94 of the 737 men died. TU (ref: non-treatment) was associated with mortality; hazard ratio = 0.23, 95% confidence intervals = 0.14-0.40. Cox's regression models showed the above association to be independent of baseline age, waist circumference, hemoglobin A1c, lipids, blood pressure, smoking, and type 2 diabetes. These variables remained associated with mortality. We finally stratified the men by the high-risk baseline variables and established that the association between mortality and TU was only evident in men at higher risk. A possible explanation could lie with the "law of initial value," where greater improvements are evident following treatment in patients with worse baseline values. CONCLUSIONS: This study with long follow-up confirms that TTh is associated with lower mortality in men with adult-onset TD. This association was evident only in men with greater cardio-metabolic risk factors who demonstrated greater benefit.

Metabolic syndrome: A review of the role of vitamin D in mediating susceptibility and outcome.

Despite the well-recognised role of vitamin D in a wide range of physiological processes, hypovitaminosis is common worldwide (prevalence 30%-50%) presumably arising from inadequate exposure to ultraviolet radiation and insufficient consumption. While generally not at the very low levels associated with rickets, hypovitaminosis D has been implicated in various very different, pathophysiological processes. These include putative effects on the pathogenesis of neoplastic change, inflammatory and demyelinating conditions, cardiovascular disease (CVD) and diabetes. This review focuses on the association between hypovitaminosis D and the metabolic syndrome as well as its component characteristics which are central obesity, glucose homeostasis, insulin resistance, hypertension and atherogenic dyslipidaemia. We also consider the effects of hypovitaminosis D on outcomes associated with the metabolic syndrome such as CVD, diabetes and non-alcoholic fatty liver disease. We structure this review into 3 distinct sections; the metabolic syndrome, vitamin D biochemistry and the putative association between hypovitaminosis D, the metabolic syndrome and cardiovascular risk.

The Multiple Sclerosis Severity Score: associations with MC1R single nucleotide polymorphisms and host response to ultraviolet radiation.

BACKGROUND: Multiple sclerosis outcome may be influenced by ultraviolet radiation and vitamin D synthesis, suggesting skin type and genes determining this phenotype are candidates for disability. However, though associations between melanocortin 1 receptor (MC1R) single nucleotide polymorphisms and disability are reported, some data are incompatible with their expected influence on skin type. OBJECTIVE: Determine which MC1R single nucleotide polymorphisms affect disability and establish if ultraviolet radiation modifies such associations. METHODS: We studied using linear regression in 525 cases, associations of the Multiple Sclerosis Severity Score (MSSS) with skin type, gender, ultraviolet radiation exposure and six MC1R single nucleotide polymorphisms (rs1805005, rs1805006, rs2228479, rs1805007, rs1805008, rs1805009). RESULTS: CG(294) with GG(294) genotypes (rs1805009) (coefficient = -1.44, 95% CI -2.30, -0.59, mean MSSS +/- SD = 4.33 +/- 2.87) and AC(84) (rs1805006) (coefficient = 1.62, 95% CI 0.17, 3.06, mean MSSS = 7.62 +/- 2.43) were associated with MSSS. Associations with Asp294His were found in those with skin types 1/2 and 3/4, and cases stratified by ultraviolet radiation exposure. However, they were seen only in cases with a history of childhood sunburn and not in those without sunburn. We found no significant associations between exposure parameters and MSSS. CONCLUSIONS: Multiple sclerosis outcome is influenced by interactions between host response to ultraviolet radiation and MC1R single nucleotide polymorphisms. The influence of the single nucleotide polymorphisms appears distinct from their association with skin type.

Patients with both basal and squamous cell carcinomas are at a lower risk of further basal cell carcinomas than patients with only a basal cell carcinoma.

BACKGROUND: The rate of development of further basal cell carcinoma (BCC) after first presentation is highly variable. The mechanisms that determine this phenotypic difference are unclear. OBJECTIVE: We assessed the risks of developing a subsequent BCC in patients who developed a BCC and a squamous cell carcinoma (SCC) and compared them with patients who developed a BCC only. METHODS: In all, 1040 patients who developed BCC only were compared with 140 patients who developed BCC and SCC to see whether the latter group included a high proportion of risk phenotypes (eg, male sex and fair skin). We then compared the number of BCCs developing per year in the two groups (174 BCC only and 71 BCC/SCC) during a 5-year period after initial BCC presentation. RESULTS: The BCC/SCC group demonstrated a significantly lower BCC/year rate than BCC only group. The rate of development of further BCC during 5-year follow-up was lower in the BCC/SCC group because a smaller number of patients developed subsequent BCC and not because the same proportion of patients developed lesions but in smaller numbers. After 5 years of follow-up, 51.1% of BCC and 74.6% of BCC/SCC cases were free from a subsequent BCC. Logistic regression analysis corrected for age at initial presentation confirmed that patients with BCC/SCC were less likely to develop a further BCC during the 5 years after initial presentation (P = .001, odds ratio = 0.31, 95% confidence interval 0.15-0.63). LIMITATIONS: Because of the large patient group and long study follow-up from the date of the index BCC or SCC, not all data were obtained. Where this is the case, the number of patients for whom the information is available is provided. CONCLUSIONS: Patients who develop a BCC are similar to patients who develop both a BCC and SCC, confirming the overlap of causative factors. Patients who develop both a BCC and SCC are less likely to develop BCCs compared with patients who develop BCC only.

Meta-analysis and pooled analysis of GSTM1 and CYP1A1 polymorphisms and oral and pharyngeal cancers: a HuGE-GSEC review.

The association of GSTM1 and CYP1A1 polymorphisms and oral and pharyngeal cancers was assessed through a meta-analysis of published case-control studies and a pooled analysis of both published and unpublished case-control studies from the Genetic Susceptibility to Environmental Carcinogens database (http://www.upci.upmc.edu/research/ccps/ccontrol/index.html ). Thirty publications used in the meta-analysis included a total of 7783 subjects (3177 cases and 4606 controls); 21 datasets, 9397 subjects (3130 cases and 6267 controls) were included in the pooled analysis. The GSTM1 deletion was 2-fold more likely to occur in African American and African cases than controls (odds ratio: 1.7, 95% confidence interval: 0.9-3.3), although this was not observed among whites (odds ratio: 1.0, 95% confidence interval: 0.9-1.1). The meta-analysis and pooled analysis showed a significant association between oral and pharyngeal cancer and the CYP1A1 MspI homozygous variant (meta-ORm2/m2: 1.9, 95% confidence interval: 1.4-2.7; Pooled ORm2m2: 2.0, 95% confidence interval: 1.3-3.1; ORm1m2 or [infi]m2m2: 1.3, 95% confidence interval: 1.1-1.6). The association was present for the CYP1A1 (exon 7) polymorphism (ORVal/Val: 2.2, 95% confidence interval: 1.1-4.5) in ever smokers. A joint effect was observed for GSTM1 homozygous deletion and the CYP1A1 m1m2 variant on cancer risk. Our findings suggest that tobacco use and genetic factors play a significant role in oral and pharyngeal cancer.

Associations between timing of exposure to ultraviolet radiation, T-stage and survival in prostate cancer.

BACKGROUND: Exposure to ultraviolet radiation (UVR) has been inversely associated with prostate cancer risk. We determined if skin type and UVR exposure are linked with parameters of prostate cancer outcome. METHODS: We used a questionnaire to determine UVR exposure parameters and skin type in 553 men with prostate cancer and, using logistic regression and survival analysis, studied their association with T-stage, Gleason score, and survival after starting hormone manipulation therapy. RESULTS: UVR exposures 10, 20, and 30 years before diagnosis were inversely associated with T-stage. The odds ratio (OR) for UVR exposure 10 years before diagnosis was lowest (OR=0.69, 95% CI=0.56-0.86). ORs were lower in men with skin types I/II than III/IV. Skin types I/II were associated with longer survival after commencing hormone therapy (hazard ratio=0.62, 95% CI=0.40-0.95). CONCLUSIONS: Our finding that UVR exposure is beneficial is compatible with accumulating data showing sunlight has a protective effect on disease phenotype.

Vitamin D and oestrogen receptor polymorphisms in developmental dysplasia of the hip and primary protrusio acetabuli--a preliminary study.

We investigated the association of developmental dysplasia of the hip (DDH) and primary protrusion acetabuli (PPA) with Vitamin D receptor polymorphisms Taq I and Fok I and oestrogen receptor polymorphisms Pvu II and Xba I. 45 patients with DDH and 20 patients with PPA were included in the study. Healthy controls (n = 101) aged 18-60 years were recruited from the same geographical area. The control subjects had a normal acetabular morphology based on a recent pelvic radiograph performed for an unrelated cause. DNA was obtained from all the subjects from peripheral blood. Genotype frequencies were compared in the three groups. The relationship between the genotype and morphology of the hip joint, severity of the disease, age at onset of disease and gender were examined. The oestrogen receptor Xba I wild-type genotype (XX, compared with Xx and xx combined) was more common in the DDH group (55.8%) than controls (37.9%), though this just failed to achieve statistical significance (p = 0.053, odds ratio = 2.1, 95% CI = 0.9-4.6). In the DDH group, homozygosity for the mutant Taq I Vitamin D receptor t allele was associated with higher acetabular index (Mann-Whitney U-test, p = 0.03). Pvu II pp oestrogen receptor genotype was associated with low centre edge angle (p = 0.07). This study suggests a possible correlation between gene polymorphism in the oestrogen and vitamin D receptors and susceptibility to, and severity of DDH. The Taq I vitamin D receptor polymorphisms may be associated with abnormal acetabular morphology leading to DDH while the Xba I oestrogen receptor XX genotype may be associated with increased risk of developing DDH. No such correlations were found in the group with PPA.

Differential effects of glutathione S-transferase pi (GSTP1) haplotypes on cell proliferation and apoptosis.

Expression of the glutathione S-transferase, GSTP1, is associated with phase 1 detoxification of the products of oxidative stress. Recently, GSTP1 expression has been implicated in the regulation of cell proliferation and apoptosis through direct interaction with the c-Jun N-terminal kinase, (JNK). GSTP1 is polymorphic and allelic variants have been associated with disease susceptibility and clinical outcome. However, the influence of GSTP1 alleles on proliferation and apoptosis has not been studied previously. To investigate this, we have examined the effects of inducible expression of wild-type GSTP1*A and mutant GSTP1*C haplotypes on cell proliferation and apoptosis in NIH3T3 fibroblasts. Cells expressing GSTP1*A displayed increased doubling times and a delayed G1-S phase transition compared with cells expressing GSTP1*C. Both GSTP1*A and GSTP1*C haplotypes protected cells from undergoing apoptosis when exposed to oxidative stress. However, analysis of JNK status revealed that only GSTP1*C expression led to a reduction in JNK activity compared with GSTP1*A-expressing cells and non-induced cells. We further examined the effect of GSTP1 alleles on colony-forming efficiency (CFE) in soft agar following exposure to oxidative stress and found that GSTP1*A-expressing clones had increased CFE compared with non-induced and GSTP1*C-expressing clones. Our data suggest that GSTP1 alleles have differential effects on proliferation and apoptosis; GSTP1*A reduces cellular proliferation and protects against apoptosis through a JNK-independent mechanism. In contrast, GSTP1*C does not influence cellular proliferation but protects cells from apoptosis through JNK-mediated mechanisms.

Evidence of gene gene interactions in lung carcinogenesis in a large pooled analysis.

To test the hypothesis of interaction among genetic variants in increasing the individual risk of cancer, we have studied the cumulative effect on lung cancer risk of variants in three metabolic genes, CYP1A1, GSTM1 and GSTT1, which are involved in the metabolism of the tobacco smoke constituents and environmental contaminants, polycyclic aromatic hydrocarbons and of other lung carcinogens. We have selected from the Genetic Susceptibility to Environmental Carcinogens pooled analysis all the studies on lung cancer conducted after 1991 in which all variants were available. The data set includes 611 cases and 870 controls. We found a cumulative effect of the combination of the a priori 'at-risk' alleles for these genes (P for trend 0.004). The risk of lung cancer was increased with the combination of CYP1A1*2B or CYP1A1*4 alleles and the double deletion of both GSTM1 and GSTT1 up to an odds ratio (OR) of 8.25 (95% confidence interval 2.29-29.77) for the combination including CYP1A1*4; among never smokers, the latter combination was associated with an OR of 16.19 (1.90-137). Estimates did not change after adjustment by the number of cigarettes smoked and duration of smoking were consistent across ethnicities and were approximately the same for adenocarcinomas and squamous cell carcinomas. These observations from a large pooled analysis strongly suggest the existence of gene-gene interactions in lung carcinogenesis. People with rare combinations of common gene variants have a high risk of cancer and can be assimilated to subjects with highly penetrant mutations.

Prostate cancer susceptibility is mediated by interactions between exposure to ultraviolet radiation and polymorphisms in the 5' haplotype block of the vitamin D receptor gene.

Vitamin D receptor (VDR) polymorphisms are prostate cancer risk candidates. We determined if SNPs in haplotype block sub-regions C2 (SNPs C2-1, G/C(3436), C2-2, A/G(3944)) or C1 (C1-1, C/T(20965), C1-2, C/T(30056)) are associated with risk in an ultraviolet radiation (UVR)-dependent manner. In men with very low exposure, SNPs in both sub-regions were associated with risk. Various haplotypes in haplotype block C including G(3436)-A(3944)-C(20965)-C(30056), (G or C)-A-C-C and G-A-(C or T)-C were significantly associated with increased risk (odds ratios between 1.95 and 2.37). These findings suggest various block C SNPs are associated with prostate cancer risk via a mechanism involving exposure to sunlight.

Associations between G/A1229, A/G3944, T/C30875, C/T48200 and C/T65013 genotypes and haplotypes in the vitamin D receptor gene, ultraviolet radiation and susceptibility to prostate cancer.

Ultraviolet radiation (UVR) may protect against prostate cancer via a mechanism involving vitamin D. Thus, the vitamin D receptor (VDR) gene is a susceptibility candidate, though published data are discrepant. We studied the association of prostate cancer risk with five VDR single nucleotide polymorphisms (SNPs): G/A(1229) (SNP 1), A/G(3944) (SNP 2), T/C(30875) (SNP 3), C/T(48200) (SNP 4) and C/T(65013) (SNP 5), in 430 cancer and 310 benign prostatic hypertrophy (BPH) patients. The SNP 2 GG genotype frequency was lower in cancer than BPH patients (odds ratio = 0.63, 95% CI = 0.41-0.98, p = 0.039). SNPs 1 and 2, and SNPs 4 and 5, were in linkage disequilibrium. Two copies of haplotypes comprising SNPs 1-2, G-G (odds ratio = 0.63, p = 0.039), SNPs 2-3 G-C (odds ratio = 0.45, p = 0.008) and SNPs 1-2-3 G-G-C (odds ratio = 0.44, p = 0.006), but not SNPs 1-3, G-C (odds ratio = 0.81, p = 0.34), were associated with reduced risk (reference, no copies of the haplotypes). These associations were observed after stratification of subjects by extent of UVR exposure. These data show that SNP 2 GG genotype mediates prostate cancer risk, complementing studies reporting this allele is protective in malignant melanoma pathogenesis. They further suggest that published associations of risk with SNP 1 may result from linkage disequilibrium with SNP 2.

Polymorphisms in the glutathione S-transferase mu cluster are associated with tumour progression and patient outcome in colorectal cancer.

Glutathione S-transferase (GST) enzymes catalyse the detoxification of by-products of reactive oxygen species and are thus important in cellular defence mechanisms. The GSTs are polymorphic with allelic variants encoding isoforms with functional differences. GST polymorphism has been associated with susceptibility and clinical outcome in patients with cancer. In this retrospective cohort, we have investigated associations between common GSTM1, GSTM3 and GSTP1 polymorphisms with factors known to influence clinical out-come and patient survival in colorectal cancer. Significant linkage disequilibrium was demonstrated between GSTM1 and GSTM3 alleles (P< or =0.001). We identified no significant associations between the GSTP1(Ile105Val105) polymorphism and any clinical outcome parameters or patient survival. However significant associations were demonstrated with mu class GSTs. Those patients who were GSTM1 null presented less frequently with poorly-differentiated tumours (P=0.038). Furthermore, patients who were GSTM3 AA were less likely to present with advanced stage tumours (T-stage, P=0.036 and Dukes' classifications, P=0.012) or distant metastases (P=0.017) when examined alone. Upon further examination of the effect of linkage disequilibrium, we found that, in GSTM1 null individuals, GSTM3 AA (compared with other GSTM3 genotypes combined) had longer disease-free survival (HR=0.54, 95% CI 0.30-0.98, P=0.044). Thus, the GSTM3 AA genotype is associated with improved prognosis especially in those with GSTM1 null. Our findings suggest that the GST mu gene cluster mediates tumour characteristics and survival in patients with colorectal cancer.

Ultraviolet radiation, vitamin D and risk of prostate cancer and other diseases.

Most common diseases appear to result from complex, poorly understood interactions between genetic and environmental factors. Relatively few factors have been unequivocally linked with disease risk or outcome. Evidence from various studies using different experimental approaches has been interpreted as showing that, apart from its harmful effects on the pathogenesis of the common skin cancers, ultraviolet radiation (UVR) may exert a beneficial effect on development of various internal cancers and other pathologies. This concept is supported by parallel studies showing that hypovitaminosis D is linked with increased risk of various diseases including insulin resistance and multiple sclerosis. These findings suggest that, first, host factors such as skin pigmentation that affect UVR-induced synthesis of vitamin D and, second, polymorphism in genes that mediate the effectiveness of vitamin D action are susceptibility candidates for a variety of diseases. Collectively, these data suggest the hypothesis that, via effects on vitamin D synthesis, UVR exposure has beneficial effects on susceptibility and outcome to a variety of complex diseases. We describe evidence from studies in various diseases, but mainly from prostate cancer patients, that supports this hypothesis, but we emphasize that, although supportive data are available, the concept is unproven. Indeed, other explanations are possible. However, given the potentially important public health implications of the hypothesis and the potential for the development of novel therapeutic modalities, we believe the concept is worthy of further investigation.

Polymorphism in the nuclear excision repair gene ERCC2/XPD: association between an exon 6-exon 10 haplotype and susceptibility to cutaneous basal cell carcinoma.

Cutaneous basal cell carcinoma (BCC) risk is mediated by interactions between ultraviolet radiation (UVR) and host factors, including DNA repair efficiency. We investigated the association between BCC risk and SNPs in exon 6 (c.466C > A, dbSNP238406:g.C > A; designated C/A156), exon 10 (c.932G > A, dbSNP1799793:g.G > A; designated G/A312), and exon 23 (c.2251A > C, dbSNP13181:g.A > C; designated A/C751) of the nucleotide excision repair gene, XPD (ERCC2; excision repair cross-complementing repair deficiency, complementation 2 [xeroderma pigmentosum D]). XPD genotype frequencies were not significantly different in 509 cases and 379 controls, although AA156 (odds ratio [OR]=0.61, 95% confidence interval [CI]=0.37-1.01, P=0.052) and AA312 (OR=0.65, 95% CI=0.40-1.05, P=0.08) were linked with reduced risk. A156-A312 and A156-A312-A751 haplotype frequencies however, were significantly lower in cases than controls (OR=0.12, 95% CI=0.05-0.31, P < 0.001; OR=0.10, 95% CI=0.03-0.33, P < 0.001). We confirmed the robustness of these findings by showing significant associations of the haplotypes with risk in two randomly selected equal sized groups of cases and controls and, using the false positive report probability (FPRP) approach (FPRP values < 0.001 and < 0.004, respectively). A156-A312 was similarly associated with reduced risk in subgroups, including cases with no family history of skin cancer, with only BCC on the head/neck, and those with a high rate of increase in BCC numbers. The association was not dependent on gender, age, or extent of UVR exposure. A156-A312 was found in 6.3% of controls and the corresponding risk haplotype, C156-G312 (OR=1.65, 95% CI=1.21-2.26, P=0.002) in 35.4% of controls. We interpret these data as showing that XPD SNP mediate susceptibility to BCC.

Associations between ultraviolet radiation, basal cell carcinoma site and histology, host characteristics, and rate of development of further tumors.

BACKGROUND: Patients with basal cell carcinoma (BCC) frequently develop further tumors during follow-up. OBJECTIVE: We sought to elucidate the relative effects of pattern of ultraviolet radiation exposure, and site and histologic type of the first tumor, on the rate of increase in BCC numbers. METHODS: We used negative binomial regression analysis to study the association of selected variables on the rate of increase in BCC numbers in 266 Caucasian patients who first presented with a tumor on the head/neck or trunk with nodular or superficial histology. RESULTS: Patients with an initial truncal BCC with superficial histology demonstrated significantly faster increases in BCC numbers than did patients with other site and histology combinations. CONCLUSIONS: These data indicate that site and histology define subsets of patients with BCC.

Ultraviolet radiation: effects on risks of prostate cancer and other internal cancers.

Governmental and research agencies worldwide have strongly advocated sun avoidance strategies in an attempt to counter marked increases in skin cancer incidence. Concurrently, there are reports describing widespread Vitamin D3 deficiency. Because 1,25-dihydroxyvitamin D3, through interaction with the Vitamin D receptor, exerts pleiotrophic effects, such deficiency might be expected to have clinical consequences. Indeed, various reports indicate that exposure to ultraviolet radiation (UVR) exerts a protective effect on development of some common diseases including internal cancers and multiple sclerosis. We describe studies indicating that modest exposure reduces risk of prostate cancer. The effect of UVR is mediated by skin type; at lower levels of exposure a relative inability to effect skin pigmentation is protective presumably because it allows more efficient Vitamin D3 synthesis. Polymorphic variants in genes associated with pigmentation including melanocyte stimulating hormone receptor and tyrosinase are also associated with prostate cancer risk. Overall, though preliminary and requiring cautious interpretation, these data indicate that moderate UVR exposure together with characteristics linked with less effective tanning confer reduced prostate cancer risk. Clearly, it is important to define safe levels of UVR that do not result in increased risk of skin cancers such as malignant melanoma.

Association of cyclin D1 polymorphism with increased susceptibility to oral squamous cell carcinoma.

We have examined the association of the CCND1 A/G870 polymorphism with susceptibility and outcome in 174 German patients with oral SCC (OSCC). The CCND1 G870 allele frequency was increased in cases (G870=0.65) when compared to controls (n=155, G870=0.54) and the distribution of CCND1 genotypes were significantly different (p=0.014). Using logistic regression, correcting for age, gender and tobacco consumption, an increased frequency of the CCND1 GG870 genotype was observed in the OSCC cases (p=0.025, OR 3.37, 95% CI 1.61-9.80). No significant associations were observed between CCND1 A/G870 and tumour histological factors. Our data suggests that the CCND1 GG870 genotype is associated with increased susceptibility to OSCC. The involvement of cyclin D1 polymorphism in mechanisms of SCC development may differ in the different sub-sites of the head and neck.