BRAF V600 mutations and pathological features in Japanese melanoma patients. Issue 1 (February 2015)

• Record Type: Journal Article
• Authors: Yamazaki, Naoya; Tanaka, Ryota; Tsutsumida, Arata; Namikawa, Kenjiro; Eguchi, Hironobu; Omata, Wataru; Oashi, Kohei; Ogawa, Toru; Hayashi, Amiko; Nakamura, Noriyuki; Tsuta, Koji
• Is Part Of: Melanoma research. Volume 25:Issue 1(2015)
• Publication Date: 2015-02
• Subjects: Melanoma -- Periodicals; Melanoma -- Periodicals; Melanomen; 616.99477
• DOI: 10.1097/CMR.0000000000000091
• Languages: English
• ISSNs: 0960-8931

Abstract

<abstract> <title> <x xml:space="preserve">Abstract</x> </title> <sec> <p>Ultraviolet radiation is a risk factor for <italic>BRAF</italic> V600 mutations frequently found in melanomas that cause constitutive BRAF activation. Primary sites of melanoma and the frequency of <italic>BRAF</italic> mutations might differ between races. Melanoma is rare in Japan (1500–2000 cases/year compared with 132 000/year worldwide) and the frequency and distribution of <italic>BRAF</italic> V600 mutations are unknown. We aimed to investigate the frequency of <italic>BRAF</italic> V600 mutations in a cohort of Japanese patients with melanoma and determine the relationship between mutations and clinical/pathologic features. DNA was extracted from 80 formalin-fixed, paraffin-embedded tumours from individuals diagnosed with melanoma. <italic>BRAF</italic> V600 mutations were detected using the Cobas 4800 System with z480 Analyzer and Cobas 4800 BRAF V600 Mutation Test reagents. <italic>BRAF</italic> V600 mutations were detected in 41.8% of tested tumours, with an invalid rate of 1.3%. The mutation rate was more than 60% in patients aged less than 60 years and more than 36% in patients with stage III/IV disease. No sex difference in the mutation rate was observed. <italic>BRAF</italic> V600 mutations were detected in 18.8% of acral lentiginous melanomas (ALMs), 64.7% of superficial spreading melanomas, 50.0% of lentigo maligna melanomas and 20.0% of nodular melanomas. Although the mutation rate was low in ALMs, 36.4% were mutation positive at stage III/IV compared with 9.5% at stage I/II. This study confirmed associations among <italic>BRAF</italic> V600 mutations, pathological features and subtypes of melanoma. <italic>BRAF</italic> V600 mutations were more frequent in late-stage ALMs than in early-stage ALMs. Superficial spreading melanomas had similar mutation rates at all stages. These insights suggest improved treatment predictions for stage III/IV melanoma patients.</p> </sec> </abstract>