8507 Background: Melanoma disproportionately affects those under 40yr compared with other solid tumors. Oncogenic BRAF mutations occur at an overall rate of approximately 50%, and are associated with younger age. No study to date has examined decade-specific BRAF mutation rates, a clinically relevant parameter in the era of MAPK-pathway targeting therapy. Obesity is associated with an increased risk of melanoma, however the association of body mass index (BMI) with BRAF mutation status is unknown. We aimed to determine the decade-specific BRAF mutation rate and genotype in metastatic melanoma, and explore its relationship with BMI. Methods: 312 consecutive BRAF-tested patients with unresectable stage IIIC and IV melanoma were analysed. Tumour samples were screened by high-resolution melt curve analysis of BRAF exon 15 with abnormal results confirmed by DNA sequencing. Data were collected to assess demographic and anthropometric variables, and details of the age at metastatic disease diagnosis. Results: 46% of the 312 patients had a BRAF mutation. Of these, 73% were V600E, 19% V600K, and 8% other genotypes. The BRAF mutation rate decreased with increasing age, particularly after age 40 (p<0.001, χ² test). Amongst those with a BRAF mutation, there was a difference in age distribution and BRAF mutation genotype (p=0.05, Kruskal Wallis test). In the subgroup of younger patients (≤40yr), there was a significant difference in BMI between BRAF mutant and wild-type (median BMI 24.3 v 28.8, p=0.03, Mann-Whitney test). Conclusions: In patients with metastatic melanoma, there is an inverse relationship between BRAF mutation rate and age. There is some evidence that BRAF mutation genotype varies with age, with V600E occurring more frequently at younger ages, and V600K at older. BRAF wild-type melanoma may be associated with higher BMI in patients ≤40yr. Phenotypic characterisation of molecular features will have increasing significance as targeted therapies develop, and may direct further research into the mechanisms of oncogenesis in melanoma. Age No. BRAF mutant V600E V600K 20-30 14 86% 83% 0% 31-40 30 80% 92% 8% 41-50 42 50% 76% 14% 51-60 58 41% 67% 29% 61-70 103 48% 71% 24% >70 65 22% 50% 21%

Correction to: British Journal of Cancer (2008) 98, 1085–1093. doi:10.1038/sj.bjc.6604281 During revision and subsequent submission of the above paper to the journal, an author's name, Rajmohan Murali, was omitted from the authors list. The complete list of authors is given above.

Scolyer, Richard A MB BS, FRCPA; Thompson, John F MD, FRACS, FACS; Warnke, Kirsten BA; McCarthy, Stanley W AO, MB BS, FRCPA Author Information

Differences in the methylation status of these TRGs in SLN(+) paediatric and adult patients with melanoma may account for why SLN(+) paediatric patients have different clinical outcomes. SLN biopsy should continue to be performed; within SLN(+) paediatric patients with melanoma, hypermethylation of TRGs can be used to identify a subpopulation at highest risk for poor outcomes who warrant vigilant clinical follow-up.

The recommended initial management for suspected melanoma is excisional biopsy. The use of partial biopsies of melanocytic tumours poses potential problems including misdiagnosis due to either unrepresentative sampling or the difficulty in evaluating important diagnostic features; an inaccurate assessment of Breslow thickness and other important prognostic features; and the induction of changes capable of mimicking melanoma (i.e., pseudomelanoma). Misdiagnosis, in turn, may lead to inappropriate management of the patient and an adverse outcome. In this report we document a previously unrecognised pitfall of partial biopsies of melanocytic tumours: implantation of tumour cells at the biopsy site potentially leading to the overestimation of tumour thickness or a misdiagnosis of the presence of microsatellites in the subsequent wide excision specimen.

The surgical treatment of melanoma has been progressively rationalised during the last two decades. Radical excision of primary tumours and elective (prophylactic) resection of regional lymph nodes have been replaced with more selective procedures that reflect improved understanding of the metastatic potential of individual tumours. Magnetic resonance spectroscopy (MRS) is an evolving technology which has the potential to diagnose many tumours and to characterise their metastatic potential. The Institute for Magnetic Resonance Research and the Sydney Melanoma Unit have developed MRS techniques to diagnose, stage and aid in the clinical management of melanoma. It is anticipated that these techniques will ultimately be used as clinical tools to provide non-surgical diagnosis of metastatic disease in sentinel nodes, either by MRS examination of a simple outpatient fine needle biopsy specimen or by use of an entirely non-invasive in vivo MRS assessment. Experience with MRS of primary breast cancers indicates that it may also be possible to predict the metastatic potential of melanoma by spectroscopic analysis of the primary tumour and to distinguish naevi from melanomas thus better selecting patients for surgery