The Expression of Galectin-1 in Melanocytic Nevus, Dysplastic Nevus and Malignant Melanoma / 대한피부과학회지

BACKGROUND: Galectin-1 (Gal-1) is a member of the galectin family of proteins, which are carbohydrate-binding proteins with an affinity for beta-galactosides. Gal-1 is differentially expressed by various normal and pathological tissues and it performs polyvalent, wide-ranging biological activities. A Gal-1 expression or over-expression in tumors and/or in the tissue surrounding them must be considered as a sign of malignant tumor progression that is often related to tumor metastasis. Although Gal-1 also plays important roles for tumorigenesis and tumor progression, the expression of Gal-1 in melanocytic nevus, dysplastic nevus and malgant melanoma has not yet been investigated. OBJECTIVE: We wanted to investigate and compare the expression of Gal-1 in melanocytic nevus, dysplastic nevusand malignant melanoma. METHODS: The paraffin-embedded specimens of 9 cases of malignant melanoma (MM), 6 cases of dysplastic nevus (DN) and 6 cases of intradermal nevus (IN) were subjected to immunohistochemical staining for Gal-1. RESULTS: The percentage of positive cells for Gal-1 in the MM was significantly higher than that of the DN and IN (p<0.01). The staining intensity of the positive cells for Gal-1 was the highest also in the MM. Meanwhile Gal-1 was more strongly expressed in highly atypical (more pleomorphic, more atypical mitoses) areas of the melanoma tissues. But there was no significant difference between the DN and IN for the expression of Gal-1. LIMITATION: This study is restricted to a small number of patients. CONCLUSION: The present study suggests that Gal-1 is more strongly expressed in malignant melanoma than in melanocytic nevus and dysplastic nevus. Interestingly, Gal-1 was more strongly expressed in the highly atypical portions of the melanoma tissue. Gal-1 might well contribute to the tumorigenesis and malignancy of melanocytes.

Melanoma lentiginoso acral: una variante de melanoma maligno de especial interés en Colombia / Acral lentiginous melanoma: a variant of malignant melanoma of special interest in Colombia

El melanoma lentiginoso acral (MLA) es una variante rápidamente progresiva del melanoma maligno (MM). Constituye el 5-10% de los MM y se presenta con mayor frecuencia en pacientes de raza negra, asiáticos y latinoamericanos. En Colombia, la frecuencia de MM se encuentra en aumento y el MLA es una de las variantes más comunes (14,7% de todos los melanomas). La edad promedio de presentación es de 58 años, con una tasa de supervivencia menor para las personas de raza negra, asociada al diagnóstico tardío. EL MLA se localiza en las plantas, palmas y regiones subungueales y en su etiopatología se ha descrito la presencia de mutaciones en varios genes: 9p21 p16: (67%), 11q13 (CCND1) (47%), 22q11-q13 (40%) y 5p15 (20%). El diagnóstico de MLA se ha fundamentado clásicamente en la histopatología; sin embargo, otros métodos como la dermatoscopia, la evaluación del ganglio centinela y la detección de alteraciones en las proteínas del ciclo celular pueden contribuir al diagnóstico precoz y a mejorar el pronóstico tanto del MLA como del MM en general.

Acral lentiginous melanoma (ALM) is a rapidly progressive variant of malignant melanoma (MM). It constitutes 5-10% of all cases of MM and its prevalence is higher in blacks, Asians and Latin Americans. In Colombia, the incidence of MM is increasing and ALM is one of its most common variants (14.7% of all melanoma cases). The mean age at presentation of the disease is 58 years, and the survival rate is lower in black people, partly due to delayed diagnoses. ALM is located in the soles, palms and subungual regions. Mutations in several genes have been described in the pathogenesis of ALM, namely: 9p21 (p16: 67%), 11q13 (CCND1) (47%), 22q11-q13 (40%) and 5p15 (20%). The diagnosis of ALM has been traditionally based on histopathology; however, other diagnostic tools such as dermoscopy, evaluation of the sentinel lymph node and detection of alterations in proteins that control the cell cycle, may contribute to earlier diagnoses and, consequently, improve the prognosis of both ALM and MM.