Measuring vitamin D levels: surrogates are insufficient.

AIMS: With the increasing evidence of adverse consequences because of low vitamin D levels on health demand for vitamin D, screening is increasing. The objective of the study was to assess whether parathyroid hormone (PTH) levels/bone profile is sufficient to identify patients with vitamin D insufficiency or deficiency, or whether vitamin D should be measured directly. METHODOLOGY: A total of 1560 serum specimens, with requests for 25-hydroxyvitamin D (25-OH vitamin D), calcium, phosphate, alkaline phosphatase (ALP), creatinine and PTH on the same sample were analysed at Salford Royal Hospital from November 2010 to November 2012. RESULTS: The prevalence of total vitamin D insufficiency or deficiency (defined as total 25-OH vitamin D < 50 nmol/l) was 62.9% (981/1560) overall, with males having higher proportions (67.2 vs. 59.3 per cent; χ(2) = 8.78, p = 0.003). There was no overall trend in mean serum adjusted calcium across categories of 25-OH vitamin D status but mean serum phosphate was significantly lower (F = 6.53, p < 0.0001) in patients with a 25-OH vitamin D level < 50 nmol/l. However in patients with vitamin D deficiency, a significant proportion had PTH, calcium, phosphate and alkaline phosphatase levels within the laboratory normal range. Even at a 25-OH vitamin D < 10 nmol/l, 71.6% had a normal PTH, 89.8% had normal serum calcium levels, 84.9% had normal phosphate levels and 81.6% had normal serum ALP. CONCLUSIONS: Therefore, despite the costs associated with the measurement of vitamin D, our findings show that no surrogate is adequate for screening for vitamin D deficiency.

People with Type Diabetes Mellitus (T1DM) self-reported views on their own condition management reveal links to potentially improved outcomes and potential areas for service improvement.

BACKGROUND: The self-management of type 1 diabetes (T1DM) has moved forward in many areas over the last 40 years. Our study asked people with T1DM what is their experience of blood glucose (BG) monitoring day to day and how this influences decisions about insulin dosing. METHODS: An on-line self-reported questionnaire containing 44 questions prepared after consultation with clinicians and patients was circulated to people with T1DM 116 responders provided completed responses. Fixed responses were allocated specific values (e.g. not confident = 0 fairly confident = 1). Multivariate regression analysis was carried out. Only those 5 factors with p-value <0.05 were retained. RESULTS: 59% of respondents were >50 years old and 66% had diabetes for >20 years, with 63% of patients reporting HbA1c results ≤8% or 64 mmol/mol. Findings included; 75% used only 1 m; 56% had used the same meter for ≥3 years; 10% had tried flash monitors; 47% were concerned about current BG level; 85% were concerned about long-term impact of higher BG. 72% of respondents keep BG level high to avoid hypoglycaemia; 25% used ≥7 mmol/L as pre-meal BG target to calculate dose; 65% were concerned they might be over/under-dosing; 83% did not discuss accuracy when choosing meter. However 85% were confident in their meter's performance. The factors that linked to LOWER HbA1c included LESS units of basal insulin (p < 0.001), HIGHER number of daily BG tests (p = 0.008), LOWER bedtime blood glucose (p = 0.009), HIGHER patient's concern over long-term impact of high BG (BG) (p < 0.009 but LOWER patient's concern over current BG values (p = 0.009). The final statistical model could explain 41% of the observed variation in HbA1c. CONCLUSION: Many people still run their BG high to avoid hypoglycaemia. Concern about the longer-term consequences of suboptimal glycaemic control was associated with a lower HbA1c and is an area to explore in the future when considering how to help people with T1DM.

The rise and fall of C-reactive protein: managing demand within clinical biochemistry.

BACKGROUND: Managing workload within the laboratory has become a key role for clinical biochemists. National benchmarking data highlighted a 31% increase in C-reactive protein (CRP) requests between 2003-2004 and 2004-2005 for the University Hospital of North Staffordshire (UHNS). The aim of this study was to examine CRP requesting patterns within the acute admissions units. METHODS: Current requesting patterns within the Accident and Emergency Department (A&E) and Medical Admissions Unit (MAU) were audited. Following discussion with clinical colleagues, the laboratory implemented agreed disease-related protocols and consultant only requesting. The impact these demand management strategies had on requesting within these units was then assessed. RESULTS: The initial data (January-June 2005) showed that the average number of requests for CRP was 918 per month from A&E and 545 per month for MAU. Implementation of demand-management strategies resulted in an overall reduction of 85% in the numbers of requests, saving the Trust approximately pound10,000 per annum. Further to the initial protocols, an IT-based logic rule was also developed to reduce CRP requests made within a 24 h time window of an initial request and educate users. CONCLUSION: This study has demonstrated that strategies to control demand at the requesting stage have been able to reduce the number of requests from acute admission units. This study forms the basis for ongoing work on inappropriate requesting and illustrates that the introduction of agreed protocols in acute settings can be used as a demand-management tool.

Epigenetic control of fetal gene expression.

Each differentiated cell type has its own epigenetic signature, which reflects its genotype, developmental history, and environmental influences, and is ultimately reflected in the phenotype of the cell and organism. Some cells undergo major epigenetic 'reprogramming' during fetal development. The proper, or improper, handling of these highly sensitive periods may have significant short-term and long-term effects on the newborn and his/her progeny. This review highlights the impact of environmental and nutritional factors on the epigenome and the potential effect of epigenetic dysregulation on maternal and fetal pregnancy outcomes, as well as possible long-term implications.

The association of sex hormone-binding globulin with mortality is mediated by age and testosterone in men with type 2 diabetes.

BACKGROUND: Serum sex hormone-binding globulin levels have been associated with mortality in adult men with type 2 diabetes (T2DM). OBJECTIVES: To confirm the association of serum sex hormone-binding globulin with mortality and then determine whether this association is mediated by age and total testosterone concentration. MATERIALS AND METHODS: We studied 364 men (median age: 66 years) with T2DM over a median follow-up of 4.3 years using the Cox regression to study associations between sex hormone-binding globulin, age, total testosterone, and mortality. RESULTS: Mortality was significantly and independently associated with sex hormone-binding globulin, age, and total testosterone. In pairwise combinations of age and sex hormone-binding globulin dichotomized by median values, the association of sex hormone-binding globulin with mortality was age-dependent. Relative to the combination of age >66 years/SHBG >35 nmol/L (mortality 22.5%), the other combinations were associated with significantly less mortality (mortality in men ≤66 years/SHBG ≤ 35 nmol/L was 3.23%). In men >66 years, SHBG ≤ 35 nmol/L was associated with decreased mortality (HR: 0.41, p = 0.037) compared with SHBG > 35 nmol/L. In men ≤66 years, there was no significant difference between those with sex hormone-binding globulin above or below the median (HR: 1.73, p = 0.56, reference: SHBG ≤ 35 nmol/L). TT < 12 nmol/L was associated with increased mortality in both age categories. Men >66 years with the reference combination of SHBG > 35 nmol/L and TT < 12 nmol/L (36.84%) nmol/L had significantly higher mortality than those with SHBG > 35 nmol/L and TT ≥ 12 (18.06%) and those with SHBG ≤ 35 nmol/L and TT < 12 nmol/L (13.79%). DISCUSSION: Our data suggest sex hormone-binding globulin and total testosterone have particular impact on mortality in men aged over 66 years. Further, in older men, the combination of high sex hormone-binding globulin levels and low total testosterone is associated with greater risk than either high sex hormone-binding globulin or low total testosterone individually. CONCLUSIONS: Our findings are compatible with data suggesting the importance of sex hormone-binding globulin lies in mediating free testosterone levels.

Polymorphism at the glutathione S-transferase locus GSTM3: interactions with cytochrome P450 and glutathione S-transferase genotypes as risk factors for multiple cutaneous basal cell carcinoma.

The influence of polymorphism in the glutathione S-transferase, GSTM3 gene on susceptibility to cutaneous basal cell carcinoma (BCC) has been investigated. We have reported previously two GSTM3 alleles, GSTM3*A and GSTM3*B, distinguished by a recognition motif for the YY1 transcription factor in GSTM3*B. In this study, immunohistochemistry was used to identify GSTM3 expression in the epidermis of skin samples from 11 controls and 9 patients with BCC. A PCR method was used to identify GSTM3*A and GSTM3*B and thereby the GSTM3 AA, GSTM3 AB, and GSTM3 BB genotypes in 300 controls and 286 Caucasians with 1-35 primary BCCs. Genotypes at GSTM1, GSTT1, and the cytochrome P450 CYP1A1 and CYP2D6 loci were also determined. Frequencies of GSTM3, GSTM1, GSTT1, CYP2D6, and CYP1A1 genotypes in the cases and controls were not different. Dividing the BCC cases into groups of 92 patients with 1 lesion and 194 patients with 2-35 lesions showed that the frequencies of GSTM3 BB (2.6%) and GSTM1 A/B (1.3%) in the group with 2-35 tumors were almost significantly lower than in the group with 1 lesion (7.6%, exact P = 0.0601, chi 2(1) = 3.390; 6.5%, exact P = 0.055, chi 2(1) = 4.946, respectively). Within the cases with 2-35 tumors, a Poisson regression model was used to identify genotypes, characteristics such as skin type, and interactions between genotypes and characteristics associated with increasing numbers of tumors. This showed, after correction for male gender and age, that GSTM3 AA was not associated with risk of increased numbers of tumors, although in combination with skin type 1, GSTM1 null, and CYP1A1 m1m1, the genotype did confer increased risk (P < 0.001, rate ratio, 2.058; P < 0.001, rate ratio, 1.606; P < 0.001, rate ratio, 1.470 respectively). The data suggest that, like other allelic GST, GSTM3 influences cancer risk. As GSTM3 AA was associated with increased tumor numbers, it appears that YY1 acts as an activator of the recognition motif in GSTM3*B.

The development of glutathione S-transferase and glutathione peroxidase activities in human lung.

The development of glutathione S-transferase and glutathione peroxidase activities has been studied in human lung cytosols. Whilst no clear change in glutathione peroxidase activity was identified, expression of the acidic glutathione S-transferase isoenzyme decreased markedly after 15 weeks of gestation so that at birth the level of activity of this isoenzyme was only about 20% of that in samples obtained during the first trimester. Basic glutathione S-transferase isoenzymes were weakly expressed during development and usually comprised less than 10% of cytosolic activity. Ion-exchange studies identified several basic isoenzymes that may correspond to the alpha, beta, gamma, delta and epsilon set previously identified in liver. Weak expression of apparently near-neutral isoenzymes was also detected; they were detected in only a few cytosols.

Studies on the expression of Cu,Zn superoxide dismutase in human tissues during development.

The developmental expression of Cu,Zn superoxide dismutase in human lung and erythrocytes has been studied using activity measurements, immunoblotting and immunohistochemistry. Enzyme activity in erythrocytes increased significantly during gestation but no developmental trend was seen in lung. Immunoblotting identified a single enzyme form that was present in a variety of tissues and immunohistochemistry showed the enzyme to have widespread distribution in lung tissue. These data indicate that Cu,Zn superoxide dismutase is consistently expressed during human development and that, unlike in other species, no late-fetal surge in expression occurs.

The human glutathione S-transferases: comparison of isoenzyme expression in normal and astrocytoma brain.

We describe expression of alpha, mu and pi class glutathione S-transferases (GST) in brain tissue from 21 controls and uninfiltrated and tumour tissue from 17 glioma patients. GST were sequentially resolved by chromatofocusing into the GST2, GST1, GST5, GST2 (5.5), GST3, GST6 sets and the contribution of each to total activity determined. The immunological identity of these isoforms was studied using immunoblotting. The pi class GST3 isoform was the major contributor to activity in control tissue (70.9%) and, uninfiltrated (75.1%) and tumour samples (82.4%). Expression was significantly greater in the tumours (P less than 0.05). Expression of alpha isoforms GST2 and GST2 (5.5) was variable with most subjects demonstrating no detectable GST2 (B1 and B2 chromatofocused monomers). An isoform termed GST2 (5.5) chromatofocussed at pH 5.5 and cross-reacted with antisera to B1. It was detected in most control and glioma patients and comprised about 5% of total activity. The contribution of GST2 and GST2 (5.5) to activity was similar in control, uninfiltrated and tumour tissue. Two mu class enzymes, GST1 and GST5, were identified. GST1 isoforms were detected in 9 of 21 control samples, the phenotype of these and matched liver samples were identical. GST1 isoforms were detected in 4 of 16 tumour samples, a significantly lower incidence than in a previously established control group. GST5 was expressed in most samples, the contribution of this locus to activity was significantly reduced in the tumours (5.2%) compared with control samples (14.5%).

Studies on the developmental expression of glutathione S-transferase isoenzymes in human heart and diaphragm.

The developmental expression of the basic, near-neutral and acidic isoenzymes of glutathione S-transferase (RX:glutathione R-transferase, EC 2.5.1.18) has been studied in heart and diaphragm. Neither these enzymes nor the putative muscle-specific GST4 isoenzyme demonstrated any developmental trends in expression. In vitro hybridisation and SDS-discontinuous polyacrylamide gel electrophoresis were used to show that the GST4 isoenzyme is a homodimer composed of monomers that have a slightly larger molecular weight than the near-neutral isoenzyme. The sensitivity of GST4 to inhibitors also appeared similar to that of the GST1 2 isoenzyme. Immunodiffusion and immunoblotting techniques were used to show that the acidic enzyme in muscle is immunologically identical to that in other tissues.

Regional variation of airway hyperresponsiveness in children with asthma.

Families with asthmatic children were recruited to take part in a multi-centre collaborative study into the genetics of asthma. Detailed phenotypic information was collected on all family members including: lung function, anthropomorphic measurements, response to methacholine challenge, skin prick testing, serum IgE measurements and a detailed nurse-administered questionnaire. Families were eligible for entry into the study if they had two children with a doctor-diagnosis of asthma. Bennett/Twin nebulisers were supplied to each centre from a single source and these were calibrated to determine gravimetric nebuliser output prior to use. Asthmatic probands from each centre had similar degrees of asthma severity and atopy. There was no significant difference in the sex ratios or ages of the probands or numbers of parents with a history of smoking in the families recruited at each centre. However, there was a significant difference in the number of children with airway hyperresponsiveness, with 90% of the North Staffordshire group but only 60% of the Sheffield group having a PC20 of <8 mg/ml for methacholine. This difference highlights the difficulty of using families from different centres in genetic and epidemiological studies.

Association of protein kinase C alpha (PRKCA) gene with multiple sclerosis in a UK population.

Twin, family and adoption studies suggest that susceptibility to multiple sclerosis is substantially mediated by genetic factors. Linkage to human chromosome 17q, homologous to a locus linked to experimental animal models of multiple sclerosis, has been widely replicated and the region likely to harbour a multiple sclerosis susceptibility gene has recently been refined to a 2.5 Mb region of 17q22-24. The candidate multiple sclerosis susceptibility gene, protein kinase C alpha (PRKCA), maps within this interval and association with 35 single-nucleotide polymorphism (SNP) markers, spanning the gene with a median spacing of 7.8 kb, was tested using a case-control approach. Single-marker genotype and estimated haplotype frequencies were compared in UK unrelated cases with multiple sclerosis (n = 184) and healthy controls (n = 340) in order to investigate association with susceptibility to disease. A haplotype of two SNPs mapping to the proximal region of the gene showed evidence for association with susceptibility (Bonferroni-corrected P value = 1.1 x 10(-5)). These findings suggest that further investigation of the PRKCA gene is warranted, particularly in cohorts with evidence of linkage to 17q22. Most of the SNPs investigated in this study were intronic and screening to identify disease-associated functional mutations is now required. Our results suggest that the promoter and proximal gene region should be not only included but prioritized in any screening strategy.

Polymorphism within the cyclin D1 gene is associated with prognosis in patients with squamous cell carcinoma of the head and neck.

We have examined the correlation of a frequent A/G polymorphism within exon 4 of the cyclin D1 gene (CCND1) with genetic susceptibility and clinical outcome in 384 patients with squamous cell carcinoma (SCC) of the head and neck. CCND1 genotype frequencies were similar in the cases and 191 controls. Furthermore, the CCND1 genotype was not associated with susceptibility to SCC of the larynx, pharynx, or oral cavity. The influence of the CCND1 genotype on clinical outcome was also assessed. We found no correlation between genotype and tumor size (T1-T4), the involvement of nodes at presentation, or patient age and gender. However, the distribution of CCND1 genotypes in cases with poorly differentiated tumors was significantly different to that in patients with well-/moderately differentiated tumors (P = 0.016; chi2(2) = 8.71). Homozygosity for CCND1*G (GG genotype) was associated with poorly differentiated tumors (G3). We used Cox's proportional hazards model to investigate the influence of the CCND1 genotype on disease-free interval. CCND1 GG was associated with reduced disease-free interval [P = 0.001; hazard ratio (HR) = 2.95; 95% confidence interval (CI) = 1.54-5.63]. This remained significant after correction for tumor differentiation (P = 0.013; HR = 2.34; 95% CI = 1.2-4.6) and tumor stage (P = 0.005; HR = 2.64; 95% CI = 1.34-5.19). Analysis of the data from patients with tumors at different sites showed that the CCND1 GG genotype was associated with reduced disease-free interval in laryngeal (P = 0.004; HR = 3.63; 95% CI = 1.44-8.83) and pharyngeal (P = 0.006; HR = 3.48; 95% CI = 1.43-8.46) tumors. This is the first report of an association between CCND1 polymorphism and prognosis in SCC of the head and neck. These data show that the CCND1 GG genotype is an independent prognostic indicator of disease-free interval and supports initial observations in non-small cell lung cancer, that polymorphism within CCND1 influences tumor behavior.

Vitamin D receptor polymorphisms are associated with altered prognosis in patients with malignant melanoma.

Calcitriol [1,25(OH)2D3], the hormonal derivative of vitamin D3, is an antiproliferative and prodifferentiation factor for several cell types, including cultured melanocytes and malignant melanoma (MM) cells. Several polymorphisms of the vitamin D receptor (VDR) gene have been described including a FokI RFLP in exon 2, BsmI, and ApaI polymorphisms in intron 8 and an adjacent TaqI RFLP in exon 9. Alterations in vitamin D/1,25(OH)2D3 levels and polymorphisms of the VDR have been shown to be associated with several systemic malignancies. We hypothesize that polymorphism in this gene may be associated with altered susceptibility and outcome in patients with MM. A hospital-based case-control study, using 316 MM cases and 108 controls, was used to assess associations with MM susceptibility. Breslow thickness, the most important single prognostic factor in MM, was used as the outcome measure. Polymorphisms at the FokI and TaqI restriction sites were determined using PCR-based methods. Polymorphism at the FokI, but not TaqI, RFLP was associated with an altered risk of MM (P = 0.014). More importantly, variant alleles were associated with increased Breslow thickness. Thus, homozygosity for variant alleles at both RFLP (ttff genotype combination) was significantly associated with thicker tumors. (> or = 3.5 mm; P = 0.001; odds ratio = 31.5). Thus, polymorphisms of the VDR gene, which would be expected to result in impaired function, are associated with susceptibility and prognosis in MM. These data suggest that 1,25(OH)2D3, the ligand of the VDR, may have a protective influence in MM, as has been proposed for other malignancies.

Association of glutathione S-transferase GSTM1 and GSTT1 null genotypes with clinical outcome in epithelial ovarian cancer.

Epithelial ovarian cancer is generally associated with a poor outcome, although the mechanisms that determine survival and progression-free interval (PFI) are unclear. Data from ovarian tumors showing associations between (a) null genotypes at the glutathione S-transferase GSTM1 and GSTT1 loci and expression of p53 protein and (b) outcome and expression of p53 suggest that polymorphism at these loci is a factor determining outcome. Accordingly, we have studied the association between the GSTM1 null and GSTT1 null genotypes and survival and PFI in 148 women with epithelial ovarian cancer. Although we did not find an association between individual genotypes and outcome, women with both GSTM1 null and GSTT1 null genotypes demonstrated poorer survival (P = 0.001) and reduced PFI (P = 0.003). Thus, no cases with both these genotypes survived past 42 months postdiagnosis. In contrast, 43% of the women without this combination survived beyond this time. Because response to chemotherapy is a major factor determining outcome in ovarian cancer, we also examined the data for associations between the glutathione S-transferase genotypes and response to such treatment. Thus, in 78 patients treated with chemotherapy, the combination of GSTM1 null and GSTT1 null was associated with unresponsiveness to primary chemotherapy (P = 0.004); none of the eight patients with both these genotypes responded, compared with 38 of 70 (54%) of patients with other genotype combinations. The effect of the combination of genotypes on survival and PFI was lost in a multivariate model that included response to chemotherapy as a confounding factor. This suggests that the combination of GSTM1 null/GSTT1 null is associated with outcome because of its influence on response to chemotherapy. These preliminary findings may provide a basis for the selection of patients for treatment with chemotherapeutic agents.

Polymorphisms in glutathione S-transferases are associated with altered risk of nonmelanoma skin cancer in renal transplant recipients: a preliminary analysis.

Non-melanoma skin cancer (NMSC) represents a significant cause of morbidity and mortality among renal transplant recipients, with tumors behaving more aggressively than those in nontransplant patients. Not all immunosuppressed patients develop NMSC, however, and in those that do, the rate of accrual and numbers of lesions vary considerably. Though ultraviolet light is critical, it is unlikely that this alone explains the observed phenotypic diversity, suggesting the possible involvement of genetic factors. Furthermore, although twin studies in nontransplant patients with NMSC suggest a low genetic component, several genes associated with susceptibility and outcome in these patients have been identified. Thus, having previously shown that polymorphism in members of the glutathione S-transferase (GST) supergene family is associated with altered NMSC risk in nontransplant patients, we examined allelism in GSTM1, GSTP1, GSTM3, and GSTT1 in 183 renal transplant recipients. GSTM1 null was associated with increased squamous cell carcinoma (SCC) risk (p = 0.042, OR = 3.1). This remained significant after correction for age, gender, and ultraviolet light exposure (p = 0.012, OR = 8.4) and was particularly strong in patients with higher ultraviolet light exposure (e.g., sunbathing score > 3, p = 0.003, OR = 11.5) and in smokers (p = 0.021, OR = 4.8). Analysis of the interaction between GSTM1 null and sunbathing score showed that the two factors were synergistic and individuals with both risk parameters demonstrated a shorter time from transplantation to development of the first SCC (p = 0.012, hazard ratio = 7.1). GSTP1*Ile homozygotes developed larger numbers of SCC (p = 0.002, rate ratio = 7.6), particularly those with lower ultraviolet light exposure and cigarette consumption. GSTM3 and GSTT1 also demonstrated significant associations, though some genotype frequencies were low. These preliminary data suggest that genetic factors mediating protection against oxidative stress are important in NMSC development in immunosuppressed patients and may be useful in identifying high-risk individuals.

Truncal tumor site is associated with high risk of multiple basal cell carcinoma and is influenced by glutathione S-transferase, GSTT1, and cytochrome P450, CYP1A1 genotypes, and their interaction.

Basal cell carcinoma (BCC) places increasing burdens on clinicians; incidence is rising and patients may develop multiple primary tumors. Although UV exposure is critical, many patients develop tumors at less-exposed sites, such as the trunk, suggesting a genetic predisposition. We previously showed that polymorphism in loci encoding the detoxifying enzymes, glutathione S-transferase (GSTM1, GSTM3, GSTT1) and cytochrome P450 (CYP2D6, CYP1A1) influences susceptibility to BCC. We now describe a case-control approach in 345 patients with BCC that examines the role of these polymorphisms and patient characteristics (age, gender, skin type, hair color, eye color, smoking, occupation) in determining susceptibility to truncal tumors. GST and CYP genotypes were identified using polymerase chain reaction-based methods. Patients with one or more truncal tumors were significantly younger (p = 0.0170) than those with no truncal tumors. Male gender also appeared more common in the truncal tumor group, although this did not achieve significance (p = 0.0925). Patients whose first tumor was truncal had significantly more tumors (p = 0.0297). GSTT1 null (p = 0.0245, odds ratio 2.24) and CYP1A1 Ile/Ile (p = 0.0386, odds ratio 2.86) were associated with truncal site after correction for age and gender. The combination, GSTT1 null and CYP1A1 Ile/Ile, was particularly significant (p = 0.0059, odds ratio = 2.95). These effects were present after correction for tumor numbers. These data show first, patients with truncal tumors constitute a high-risk group for BCC, second, a significant genetic influence on BCC site, and third, a significant interaction between GSTT1 and CYP1A1 genotypes.

Susceptibility to melanoma: influence of skin type and polymorphism in the melanocyte stimulating hormone receptor gene.

Allelic variation at the melanocyte stimulating hormone receptor (MC1R) gene has been linked with sun-sensitive skin types, suggesting it is a susceptibility candidate for melanoma. We determined the frequency of the val92met, asp294his, and asp84glu MC1R alleles in 190 Caucasian controls and 306 melanoma cases and studied their association with skin type and hair color. The percentage of controls with at least one val92met, asp294his, or asp84glu allele was 17.3%, 6.8%, and 3.5%, respectively. Individually, frequencies of the val92met, asp294his, or asp84glu alleles in the controls with skin types 3 and 4 were similar to those with skin types 1 and 2. Trend analysis, however, did identify an association (exact p = 0.048, two-sided test) between skin type and MC1R variants in the group comprising all controls with any one or more of these alleles. There was no association between MC1R alleles and hair color. Allele frequencies were not different in melanoma cases and controls. There were no associations between skin types and the proportion of cases with the asp294his or asp84glu alleles, though the association between skin type and the val92met allele approached significance (exact p = 0.09, two-sided test). Unexpectedly, in the group comprising all cases with one or more variant alleles, the proportion of subjects with variant alleles increased with skin types associated with tanning rather than burning, although trend analysis showed that this association did not quite reach statistical significance (exact p = 0.08, two-sided test). Asp84glu (but not val92met or asp294his) variant alleles were more common in subjects with blonde hair, although the relationship between the asp84glu allele and hair color did not achieve statistical significance (chi(2)3 = 6.16, exact p = 0.10). We interpret the data presented as indicating that polymorphism at MC1R does not appear a major determinant of skin type, at least in terms of these allelic variants. Furthermore, considered alone, these alleles are not susceptibility candidates for malignant melanoma.

Basal cell carcinomas: association of allelic variants with a high-risk subgroup of patients with the multiple presentation phenotype.

Previous studies have shown that patients who present at first or a later presentation with a cluster of new basal cell carcinoma (BCC) comprise a subgroup, termed multiple presentation phenotype (MPP), that is at increased risk of developing further lesions. In this study, we examined the hypothesis that patients who develop multiple clusters are a high-risk subgroup. We found, in a total group of 926 BCC patients, 32 patients with 2-5 BCC clusters (multiple cluster MPP) and 113 cases with only one cluster (single cluster MPP). Multiple cluster MPP cases had mean of 11.3 BCC compared with 3.7 in single cluster MPP cases during similar follow-up. Ultraviolet (UV) exposure in these groups was similar. We determined whether the multiple cluster MPP was associated with characteristics associated with sensitivity to UV or glutathione S-transferase (GST) GSTT1, GSTM1, cytochrome P450 (CYP) CYP2D6, tumour necrosis factor (TNF)-alpha and vitamin D receptor (VDR) genotypes previously associated with BCC presentational phenotypes. While the frequencies of blue eyes and male gender were greater in multiple cluster than single cluster cases, these differences were not significant. In multiple cluster cases, mean age at first presentation with single tumours occurred earlier and the frequencies of CYP2D6 extensive metabolizer (EM) (94.4%) and GSTT1 null (41.2%) were significantly greater (P = 0.028 and P = 0.004) than in single cluster cases (67.1% and 14.3%, respectively). The odds ratios for the individual associations of CYP2D6 EM and GSTT1 null with the multiple cluster MPP were relatively larger; 15.5 and 7.39, respectively. TNF-alpha and VDR genotypes were not associated with multiple cluster MPP. We propose that the MPP is not the consequence of excessive UV exposure but rather reflects the presence of a distinct BCC subgroup which is defined by combinations of risk genes.