Evaluation of the ESMO-Magnitude of Clinical Benefit Scale version 1.1 (ESMO-MCBS v1.1) for adjuvant radiotherapy in breast cancer.

BACKGROUND: The European Society of Medical Oncology (ESMO) has suggested using the ESMO-Magnitude of Clinical Benefit Scale (MCBS) to grade the magnitude of clinical benefit of cancer therapies. This approach has not been applied to radiation therapy (RT) yet. We applied the ESMO-MCBS to experiences describing the use of RT to assess (1) the 'scoreability' of the data, (2) evaluate the reasonableness of the grades for clinical benefit and (3) identify potential shortcomings in the current version of the ESMO-MCBS in its applicability to RT. MATERIALS AND METHODS: We applied the ESMO-MCBS v1.1 to a selection of studies in radiotherapy that had been identified as references in the development of American Society for Radiation Oncology (ASTRO) evidence-based guidelines on whole breast radiation. Of the 112 cited references, we identified a subset of 16 studies that are amenable to grading using the ESMO-MCBS. RESULTS: Of the 16 studies reviewed, 3/16 were scoreable with the ESMO tool. Six of 16 studies could not be scored because of shortcomings in the ESMO-MCBS v1.1: (1) in 'non-inferiority studies', there is no credit for improved patient convenience, reduced patient burden or improved cosmesis; (2) in 'superiority studies' evaluating local control as a primary endpoint, there is no credit for the clinical benefit such as reduced need for further interventions. In 7/16 studies, methodological deficiencies in the conduct and reporting were identified. CONCLUSIONS: This study represents a first step in determining the utility of the ESMO-MCBS in the evaluation of clinical benefit in radiotherapy. Important shortcomings were identified that would need to be addressed in developing a version of the ESMO-MCBS that can be robustly applied to radiotherapy treatments. Optimization of the ESMO-MCBS instrument will proceed to enable assessment of value in radiotherapy.

Quality of life, walking ability and change of living situation after trochanteric femur fracture in geriatric patients-Comparison between sliding hip screw and cephalomedullary nails from the registry for geriatric trauma.

BACKGROUND: There is no well-established gold standard for treating trochanteric femur fractures in the elderly. The two common treatment options are cephalomedullary nails (CMN) and sliding hip screws (SHS). In this study, treatment using CMN and SHS were compared for a cohort of patients older than 70 years of age: The main outcomes were quality of life and main residence after surgery. METHODS: In this retrospective study we analyzed 24,919 patients from 100 hospitals, treated between 2016 and 2019 and documented in the Registry for Geriatric Trauma. The impact of CMN vs. SHS on the walking ability, quality of life (QoL), living situation, mortality, and revision rate were analyzed. To analyze the change of the living situation, the main residence 120 days after surgery for patients, who lived in their own home before fracture, was described for both groups. FINDINGS: A total of 10,995 patients could be included of which 10,436 patients were treated with CMN and 369 patients with SHS. 120 days postoperative the QoL differed significantly (p = 0.020) in favor of treatment using CMN. 26% of the SHS group who lived at home prior to surgery had to reside in a nursing home after surgery, whereas the rate was only 18% in the CMN group (p < 0.001). No significant difference in the mortality rate nor a difference in the walking ability 120 days postoperative were found. CMN were implanted more promptly (median: 13.9 vs. 18.4 hours; p < 0,001). No differences were found concerning the revision rate between the two groups, neither during inpatient treatment (p = 0.723) nor during the 120 day follow-up period (p = 0.524). INTERPRETATION: There might be a benefit for geriatric patients with trochanteric femur fractures to be treated with a proximal femur nail in regard to a higher QoL and a reduced institutionalization rate. Mortality or revision rate was not affected by the chosen implant.

Targeted and Systematic Biopsy for Diagnosis and Management of Prostate Cancer.

The value of multi-parametric magnetic resonance imaging in the detection of clinically-significant prostate cancer is increasingly well-established, and has been adopted in current diagnostic pathways and clinical guidelines. Concurrently, the role of conventional ultrasound-guided systematic prostate biopsy is increasingly questioned. In this brief review, we evaluate the continued value of systematic biopsy including a review of prospective studies on targeted and systemic biopsies in the same patients. We also address current limitations of multi-parametric magnetic resonance imaging of the prostate.

A tissue-mimicking prostate phantom for 980 nm laser interstitial thermal therapy.

Purpose: To develop a phantom with optical and thermal properties matched to human prostate. This phantom will provide a platform for the development and characterization of 980 nm laser interstitial thermal therapy (LITT) systems. Methods: A polyacrylamide gel was doped with Naphthol Green B, Intralipid, and Bovine Serum Albumin (BSA). The necessary concentration of each ingredient was determined by measuring the optical properties via fluence measurements and light diffusion theory. LITT was then performed under the same conditions as a previous clinical trial in which temperature was monitored via a thermal probe. The thermal data and induced coagulation zone were compared to clinical data to illustrate the similarity between the phantom and patient. LITT was also performed under magnetic resonance thermometry (MRT). Results: The requisite concentrations of Naphthol Green B, Intralipid and BSA were found to be 0.144% (w/v), 8.06% (v/v) and 31.4% (v/v) respectively. In the native state, the absorption coefficient and reduced scattering coefficient ( µs' ) were found to be 0.66 ± 0.06 cm-1 and 8.27 ± 0.50 cm-1 respectively, with µs' increasing to 17.63 ± 1.41 cm-1 after coagulation. The thermal response of the phantom was similar to that observed clinically with maximum thermal probe measurements of 64.2 °C and 66.9 °C respectively. The shape of the induced coagulation zone was qualitatively and quantitatively similar to the MRT zone of elevated temperature and the coagulation zone observed clinically. Conclusions: A phantom which simulates optical and thermal response to 980 nm LITT was constructed and demonstrated to be similar to human prostate.

Focal laser ablation as clinical treatment of prostate cancer: report from a Delphi consensus project.

PURPOSE: To define the role of focal laser ablation (FLA) as clinical treatment of prostate cancer (PCa) using the Delphi consensus method. METHODS: A panel of international experts in the field of focal therapy (FT) in PCa conducted a collaborative consensus project using the Delphi method. Experts were invited to online questionnaires focusing on patient selection and treatment of PCa with FLA during four subsequent rounds. After each round, outcomes were displayed, and questionnaires were modified based on the comments provided by panelists. Results were finalized and discussed during face-to-face meetings. RESULTS: Thirty-seven experts agreed to participate, and consensus was achieved on 39/43 topics. Clinically significant PCa (csPCa) was defined as any volume Grade Group 2 [Gleason score (GS) 3+4]. Focal therapy was specified as treatment of all csPCa and can be considered primary treatment as an alternative to radical treatment in carefully selected patients. In patients with intermediate-risk PCa (GS 3+4) as well as patients with MRI-visible and biopsy-confirmed local recurrence, FLA is optimal for targeted ablation of a specific magnetic resonance imaging (MRI)-visible focus. However, FLA should not be applied to candidates for active surveillance and close follow-up is required. Suitability for FLA is based on tumor volume, location to vital structures, GS, MRI-visibility, and biopsy confirmation. CONCLUSION: Focal laser ablation is a promising technique for treatment of clinically localized PCa and should ideally be performed within approved clinical trials. So far, only few studies have reported on FLA and further validation with longer follow-up is mandatory before widespread clinical implementation is justified.

The association of psychosocial screening and service provision in pediatric oncology: the Psychosocial Assessment Tool (PAT2.0) into clinical practice.

PURPOSE: Distress screening in oncology has been widely endorsed in recent years. However, current knowledge of the impact of screening on delivery of clinical psychosocial services is limited. This study investigated the association between screening and psychosocial services in the early period following diagnosis of childhood cancer. METHODS: The Psychosocial Assessment Tool (PAT2.0) was administered by clinical social workers in two pediatric oncology centers shortly following diagnosis. Psychosocial service activity in the first 8 weeks post diagnosis was collected via social work surveys and extraction of information from hospital databases. RESULTS: PAT2.0 and psychosocial service data were obtained for 89 families with a child newly diagnosed with cancer. Distribution of PAT2.0 risk categories was consistent with previous studies (57.3 % universal, 38.2 % targeted, 4.5 % clinical). Significant, weak to moderate correlations between PAT2.0 and social workers' estimates of psychosocial risk were observed. No significant differences in the amount of psychosocial services provided to families with "universal" versus "elevated" (i.e., targeted or clinical) risk were found. Number of days in hospital was strongly and positively associated with the amount of psychosocial services families received in the first 8 weeks following diagnosis. CONCLUSIONS: Psychosocial risk, as measured by the PAT2.0, and allocation of psychosocial services were not significantly associated in the early period following diagnosis. Further investigation is required to understand if differences emerge over time when psychosocial screening is implemented clinically. Development of clinical pathways of care needs to account for patients who may predominantly be treated in the outpatient setting.

Novel technique for characterizing prostate cancer utilizing MRI restriction spectrum imaging: proof of principle and initial clinical experience with extraprostatic extension.

BACKGROUND: Standard magnetic resonance imaging (MRI) of the prostate lacks sensitivity in the diagnosis and staging of prostate cancer (PCa). To improve the operating characteristics of prostate MRI in the detection and characterization of PCa, we developed a novel, enhanced MRI diffusion technique using restriction spectrum imaging (RSI-MRI). METHODS: We compared the efficacy of our novel RSI-MRI technique with standard MRI for detecting extraprostatic extension (EPE) among 28 PCa patients who underwent MRI and RSI-MRI prior to radical prostatectomy, 10 with histologically proven pT3 disease. RSI cellularity maps isolating the restricted isotropic water fraction were reconstructed based on all b-values and then standardized across the sample with z-score maps. Distortion correction of the RSI maps was performed using the alternating phase-encode technique. RESULTS: 27 patients were evaluated, excluding one patient where distortion could not be performed. Preoperative standard MRI correctly identified extraprostatic the extension in two of the nine pT3 (22%) patients, whereas RSI-MRI identified EPE in eight of nine (89%) patients. RSI-MRI correctly identified pT2 disease in the remaining 18 patients. CONCLUSIONS: In this proof of principle study, we conclude that our novel RSI-MRI technology is feasible and shows promise for substantially improving PCa imaging. Further translational studies of prostate RSI-MRI in the diagnosis and staging of PCa are indicated.

The oral health status of special olympics athletes in Belgium.

OBJECTIVES: To describe and evaluate the oral condition and oral treatment needs of the participants of the Special Olympics Special Smiles program organised in Belgium in 2008. DESIGN: A cross-sectional study where the data were collected through interviews and clinical examinations. PARTICIPANTS: 687 Belgian Special Smiles athletes participated, mean age 33 years. RESULTS: More than 70% had at least one missing tooth. Distinct signs of gingivitis and visible caries experience were observed in 44% and 22% of dentate athletes respectively. Dutch-speaking athletes were less likely to present with untreated caries (OR: 0.46; 95% CI: 0.31-0.68) or with gingivitis (OR: 0.51; 95% CI: 0.37-0.71) compared to their French-speaking colleagues. Signs of past injury were identified in 12% of athletes. Of those athletes with an edentulous mandible, only 53% presented with a removable denture; 73% of athletes missing some maxillary anterior teeth and 30% of those missing all anterior teeth had no prosthetic replacement in the maxilla. Nearly two fifths of athletes were referred for treatment: in 12% of athletes dental treatment was considered urgent. CONCLUSION: The results suggest that there is a tremendous unmet need for dental treatment in the Belgian Special Smiles population, with French-speaking athletes in greatest need. Improvements in data collection should be encouraged for example. more detailed screening methods (e.g. caries screening including enamel lesions, full periodontal examination) and questionnaires (e.g. inclusion of questions related to dietary habits, dental attendance). In this way barriers to optimal oral health (care) in this population could be further explored, attempts made to reduce them and so reduce health inequalities.

A methodology for selecting the beam arrangement to reduce the intensity-modulated radiation therapy (IMRT) dose to the SPECT-defined functioning lung.

Macroaggregated albumin single-photon emission computed tomography (MAA-SPECT) provides a map of the spatial distribution of lung perfusion. Our previous work developed a methodology to use SPECT guidance to reduce the dose to the functional lung in IMRT planning. This study aims to investigate the role of beam arrangement on both low and high doses in the functional lung. In our previous work, nine-beam IMRT plans were generated with and without SPECT guidance and compared for five patients. For the current study, the dose-function histogram (DFH) contribution for each of the nine beams for each patient was calculated. Four beams were chosen based on orientation and DFH contributions to create a SPECT-guided plan that spared the functional lung and maintained target coverage. Four-beam SPECT-guided IMRT plans reduced the F(20) and F(30) values by (16.5 +/- 6.8)% and (6.1 +/- 9.2)%, respectively, when compared to nine-beam conventional IMRT plans. Moreover, the SPECT-4F Plan reduces F(5) and F(13) for all patients by (11.0 +/- 8.2)% and (6.1 +/- 3.6)%, respectively, compared to the SPECT Plan. Using fewer beams in IMRT planning may reduce the amount of functional lung that receives 5 and 13 Gy, a factor that has recently been associated with radiation pneumonitis.

Cranial suture biology and dental development: genetic and clinical perspectives.

Premature fusion of the calvarial bones at the sutures, or craniosynostosis (CS), is a relatively common birth defect (1:2000-3000) frequently associated with limb deformity. Patients with CS may present oral defects, such as cleft soft palate, hypodontia, hyperdontia, and delayed tooth eruption, but also unusual associations of major dental anomalies such as taurodontism, microdontia, multiple dens invaginatus, and dentin dysplasia. The list of genes that are involved in CS includes those coding for the different fibroblast growth factor receptors and a ligand of ephrin receptors, but also genes encoding transcription factors, such as MSX2 and TWIST. Most of these genes are equally involved in odontogenesis, providing a pausible explanation for clinical associations of CS with dental agenesis or tooth malformations. On the basis of the present knowledge on genes and transcription factors that are involved in craniofacial morphogenesis, and from dental clinics of CS syndromes, the molecular mechanisms that control suture formation and suture closure are expected to play key roles in patterning events and development of teeth. The purpose of this article is to review and merge the recent advances in the field of suture research at the genetic and cellular levels with those of tooth development, and to apply them to the dental clinics of CS syndromes. These new perspectives and future challenges in the field of both dental clinics and molecular genetics, more in particular the identification of possible candidate genes involved in both CS and dental defects, are discussed.

Phase I/II examination of transurethral ethanol ablation of the prostate for the treatment of symptomatic benign prostatic hyperplasia.

PURPOSE: We assessed the safety of transurethral ethanol ablation of the prostate as a treatment for men with symptomatic benign prostatic hyperplasia and determined the efficacy of this procedure. MATERIALS AND METHODS: We performed a multicenter randomized trial on 79 men, 50 to 79 years old, who had drug refractory voiding symptoms (International Prostate Symptom Score greater than 12) and prostate volumes of 30 to 80 cc. Ethanol was injected transurethrally into the prostate with a curved cystoscopic needle in men randomly assigned to 1 of 3 doses: 15%, 25% or 40% of prostate volume by transrectal ultrasound. Followup evaluations were performed 1, 3 and 6 months later. Postoperative cystoscopy was performed on all patients to evaluate ablation extent and extraprostatic effects. Transrectal ultrasound volume determinations were obtained before and 6 months after transurethral ethanol ablation of the prostate. RESULTS: Adverse events were generally mild or moderate, and included hematuria (42.9%), irritative voiding symptoms (40.3%), pain/discomfort (25.6%) and urinary retention (22.1%). No serious adverse events were reported. Statistically significant improvements were seen in International Prostate Symptom Score, quality of life, maximum flow rate and prostate volume reduction (p<0.05). Improvements were consistently observed across the 3 groups without an apparent dose effect. CONCLUSIONS: In this randomized clinical trial transurethral ethanol ablation of the prostate was safe and effective at 6-month followup. No serious adverse events were encountered. Although ethanol can safely ablate prostatic tissue, further studies will be necessary before widespread clinical application.

A randomized phase III comparative trial of immediate consolidation with high-dose chemotherapy and autologous peripheral blood progenitor cell support compared to observation with delayed consolidation in women with metastatic breast cancer and only bone metastases following intensive induction chemotherapy.

The prognosis for patients with metastatic breast cancer remains poor. Metastatic breast cancer confined to the bones may have a better prognosis, especially hormone receptor-positive disease. We performed a prospective, randomized clinical trial to compare immediate consolidation with high-dose chemotherapy and hematopoietic support versus observation with high-dose consolidation at the time of disease progression in women with metastatic breast cancer and only bone metastases. The patients received chemotherapy with doxorubicin, 5-fluorouracil and methotrexate before randomization. In all, 85 patients were enrolled and 69 were randomized. The median follow-up is 8.1 years from randomization. The median event-free survival (EFS) for the immediate transplant arm is 12 months and for the observation arm is 4.3 months (P<0.0001). The median overall survival for the immediate transplant arm is 2.97 years and for the observation arm 1.81 years, a difference that is not statistically significant. Immediate high-dose chemotherapy and radiation therapy as consolidation offers a clinically and statistically significant improvement in EFS compared with radiation therapy alone following induction chemotherapy for women with metastatic breast cancer confined to the bones.

Enlarged prostate: a landmark national survey of its prevalence and impact on US men and their partners.

This questionnaire-based survey evaluated the frequency and severity of lower urinary tract symptoms (LUTS) and the prevalence of enlarged prostate (EP) diagnosis and its impact on quality of life and spousal relationships among >1000 American men aged >50 years. A quarter of men suffered moderate to severe LUTS and 55% of those consulting a doctor had EP. EP negatively affected patient quality of life and caused relationship strain with spouses. These findings confirm that LUTS and EP are prevalent in the US population, affecting both patient and spouse, and may help in developing management strategies for EP.

The impact of pre-radiotherapy surgery on radiation-induced lung injury.

AIMS: The use of postoperative radiation therapy (PORT) is predicated by an assessment of the potential benefits and risks, including radiation-induced lung injury. In this study, the risk of radiation-induced lung injury is assessed in patients who received PORT, and compared with a group of patients who received radiation without prior surgery, to determine if surgery increases the risk of radiation pneumonitis. MATERIALS AND METHODS: From 1991 to 2003, 251 patients with lung cancer were enrolled into a prospective study to assess radiation-induced lung injury. All patients received three-dimensional-planned, external-beam radiotherapy. One hundred and seventy-seven patients with over 6-months follow-up were eligible. For the current analysis, 49 patients (28%) had surgical intervention before radiotherapy. The rates of Grade 2 symptomatic pneumonitis in subgroups, based on the type of pre-radiation surgery, were computed and compared using Fisher's Exact Test. To consider the confounding factor of irradiated lung volume, patient subgroups were further defined on the basis of the mean lung dose. RESULTS: Surgical procedures included pneumonectomy (n=9), lobectomy (n=16), wedge resection (n=8) and exploration without resection (n=16). Radiation-induced lung injury occurred in 33 out of 177 (19%) patients, including 18% of the surgical group and 19% of the non-surgical group. Additionally, no statistically significant difference was found in the rate of radiation-induced lung injury based on the extent of resection. CONCLUSIONS: The incidence of pneumonitis is similar in the surgical and non-surgical groups. Thus, PORT may be safely given to selected patients after surgical exploration or resection.

A report of a national mutation testing service for the MEN1 gene: clinical presentations and implications for mutation testing.

INTRODUCTION: Mutation testing for the MEN1 gene is a useful method to diagnose and predict individuals who either have or will develop multiple endocrine neoplasia type 1 (MEN 1). Clinical selection criteria to identify patients who should be tested are needed, as mutation analysis is costly and time consuming. This study is a report of an Australian national mutation testing service for the MEN1 gene from referred patients with classical MEN 1 and various MEN 1-like conditions. RESULTS: All 55 MEN1 mutation positive patients had a family history of hyperparathyroidism, had hyperparathyroidism with one other MEN1 related tumour, or had hyperparathyroidism with multiglandular hyperplasia at a young age. We found 42 separate mutations and six recurring mutations from unrelated families, and evidence for a founder effect in five families with the same mutation. DISCUSSION: Our results indicate that mutations in genes other than MEN1 may cause familial isolated hyperparathyroidism and familial isolated pituitary tumours. CONCLUSIONS: We therefore suggest that routine germline MEN1 mutation testing of all cases of "classical" MEN1, familial hyperparathyroidism, and sporadic hyperparathyroidism with one other MEN1 related condition is justified by national testing services. We do not recommend routine sequencing of the promoter region between nucleotides 1234 and 1758 (Genbank accession no. U93237) as we could not detect any sequence variations within this region in any familial or sporadic cases of MEN1 related conditions lacking a MEN1 mutation. We also suggest that testing be considered for patients <30 years old with sporadic hyperparathyroidism and multigland hyperplasia.

Stromal-epithelial measurements of prostate cancer in native Japanese and Japanese-American men.

We measured the histologic stromal and epithelial tissue components of the benign (normal) and malignant tissue compartments of Japanese-Americans (J-A) and native Japanese (NJ) men living in Japan. The patient cohort included 25 NJ men undergoing radical prostatectomy (RP) in Nagoya, Japan and 25 J-A (second or third generation US born). We conducted tissue image quantitation (in-house image software) of the stromal and epithelial compartments in malignant and adjacent normal tissue areas from a tissue microarray (TMA) selected from radical prostatectomy (RP) blocks. Stromal-epithelial (S-E) areas were determined using immunohistochemical stains for CAM-5.2 epithelial cytokeratin marker and the Masson trichrome stain to measure the stroma component. We observed differences in the volumes of normal and cancer epithelium and stroma within both the J-A and NJ study populations (P<0.01). Only the individual average cancer epithelium (CE) volume (JA=24.1 vs NJ=29.9) differed significantly between the NJ and J-A study populations (P=0.03). Consequently, the S-E ratio in NJ group was significantly different from that of J-A population (P=0.05). The decrease in S-E ratio noted in the malignant tissues of NJ prostate tissue may provide a biological marker for differentiation of the two groups and suggests a need for further investigations into the molecular basis for these histologic differences.

Feasibility of optimizing the dose distribution in lung tumors using fluorine-18-fluorodeoxyglucose positron emission tomography and single photon emission computed tomography guided dose prescriptions.

The information provided by functional images may be used to guide radiotherapy planning by identifying regions that require higher radiation dose. In this work we investigate the dosimetric feasibility of delivering dose to lung tumors in proportion to the fluorine-18-fluorodeoxyglucose activity distribution from positron emission tomography (FDG-PET). The rationale for delivering dose in proportion to the tumor FDG-PET activity distribution is based on studies showing that FDG uptake is correlated to tumor cell proliferation rate, which is shown to imply that this dose delivery strategy is theoretically capable of providing the same duration of local control at all voxels in tumor. Target dose delivery was constrained by single photon emission computed tomography (SPECT) maps of normal lung perfusion, which restricted irradiation of highly perfused lung and imposed dose-function constraints. Dose-volume constraints were imposed on all other critical structures. All dose-volume/function constraints were considered to be soft, i.e., critical structure doses corresponding to volume/function constraint levels were minimized while satisfying the target prescription, thus permitting critical structure doses to minimally exceed dose constraint levels. An intensity modulation optimization methodology was developed to deliver this radiation, and applied to two lung cancer patients. Dosimetric feasibility was assessed by comparing spatially normalized dose-volume histograms from the nonuniform dose prescription (FDG-PET proportional) to those from a uniform dose prescription with equivalent tumor integral dose. In both patients, the optimization was capable of delivering the nonuniform target prescription with the same ease as the uniform target prescription, despite SPECT restrictions that effectively diverted dose from high to low perfused normal lung. In one patient, both prescriptions incurred similar critical structure dosages, below dose-volume/function limits. However, in the other patient, critical structure dosage from the nonuniform dose prescription exceeded dose-volume/function limits, and greatly exceeded that from the uniform dose prescription. Strict compliance to dose-volume/ function limits would entail reducing dose proportionality to the FDG-PET activity distribution, thereby theoretically reducing the duration of local control. Thus, even though it appears feasible to tailor lung tumor dose to the FDG-PET activity distribution, despite SPECT restrictions, strict adherence to dose-volume/function limits could compromise the effectiveness of functional image guided radiotherapy.

Genetic association and cellular function of MC1R variant alleles in human pigmentation.

We have examined MC1R variant allele frequencies in the general population of South East Queensland and in a collection of adolescent dizygotic and monozygotic twins and family members to define statistical associations with hair and skin color, freckling, and mole count. Results of these studies are consistent with a linear recessive allelic model with multiplicative penetrance in the inheritance of red hair. Four alleles, D84E, R151C, R160W, and D294H, are strongly associated with red hair and fair skin with multinomial regression analysis showing odds ratios of 63, 118, 50, and 94, respectively. An additional three low-penetrance alleles V60L, V92M, and R163Q have odds ratios 6, 5, and 2 relative to the wild-type allele. To address the cellular effects of MC1R variant alleles in signal transduction, we expressed these receptors in permanently transfected HEK293 cells. Measurement of receptor activity via induction of a cAMP-responsive luciferase reporter gene found that the R151C and R160W receptors were active in the presence of NDP-MSH ligand, but at much reduced levels compared with that seen with the wild-type receptor. The ability to stimulate phosphorylation of the cAMP response element binding protein (CREB) transcription factor was also apparent in all stimulated MC1R variant allele-expressing HEK293 cell extracts as assessed by immunoblotting. In contrast, human melanoma cell lines showed wide variation in the their ability to undergo cAMP-mediated CREB phosphorylation. Culture of human melanocytes of known MC1R genotype may provide the best experimental approach to examine the functional consequences for each MC1R variant allele. With this objective, we have established more than 300 melanocyte cell strains of defined MC1R genotype.

The human melanocortin-1 receptor locus: analysis of transcription unit, locus polymorphism and haplotype evolution.

The complete sequence of the MC1R locus has been assembled, the coding region of the gene is intronless and placed within a 12 kb region flanked by the NULP1 and TUBB4 genes. The immediate promoter region has an E-box site with homology to the M-box consensus known to bind the microphthalmia transcription factor (MITF); however, promoter deletion analysis and transactivation studies have failed to show activation through this element by MITF. Polymorphism within the coding region, immediate 5' promoter region and a variable number tandem repeat (VNTR) minisatellite within the locus have been examined in a collection of Caucasian families and African individuals. Haplotype analysis shows linkage disequilibrium between the VNTR and MC1R coding region red hair variant alleles which can be used to estimate the age of these missense changes. Assuming a mean VNTR mutation rate of 1% and a star phylogeny, we estimate the Arg151Cys variant arose 7500 years before the present day, suggesting these variants may have arisen in the Caucasian population more recently than previously thought.