Fluorescence in situ hybridization for diagnosis of malignant melanoma using RREB1, MYB, Cep6, and CCND1 probes in Japanese patients

摘要

Misdiagnosis of malignant melanoma can result in adverse patient outcomes. What if there was an easy way for dermatologists to reduce the incidence of melanoma misdiagnosis? Histological diagnosis is the gold standard for diagnosing melanoma. However, dermatopathologists sometimes have difficulty in diagnosing some melanocytic lesions. In an effort resolve this, the diagnostic methods for melanocytic lesions have been improved, and many novel diagnostic tests have been proposed: one of these employs fluorescence in situ hybridization (FISH), which detects the amplification or loss of specific DNA sequences on chromosomes. In 2007, Abbott Molecular Laboratories (Des Plaines, IL, USA) developed and manufactured a multicolor FISH probe kit to assist dermatologists in diagnosing melanocytic lesions. This kit consists of a mix of four probes, including three locus-specific identifier probes for RREB1 (located at 6p25, Spectrum Red), MYB (located at 6q23, Spectrum Gold), and CCND1 (located at 11q13, Spectrum Green), and a centromeric probe (Cep6, Spectrum Aqua).1 While the protocol used for traditional FISH is complicated, using the commercially available multicolor FISH probe kit simplifies the technique. In Europe and the United States, FISH has often been used as complementary method to improve the accuracy of melanocytic lesion diagnosis.1, 2 In Japan, there are few reports on the application of traditional FISH for the diagnosis of melanoma;3 however, there is no report employing the multicolor FISH probe kit. Herein, we present two cases in which melanoma FISH was used to detect gene alternation. This is the first report on the use of multicolor FISH probe kit to detect gene amplification in Japanese patients.