BACKGROUND: Though acral lentiginous melanoma (ALM) is a major type of malignant melanoma, no immunohistochemical study on this type of melanoma has been reported. OBJECTIVE: The purpose of this study is to analysis the immunohistochemical findings of ALM using routinely used immune markers. METHODS: An immunohistochemical study was performed on paraffin sections of 20 ALMs using S-100 protein, HMB-45, MART-1, vimentin, epithelial membrane antigen (EMA) and CAM 5.2. RESULTS: S-100 protein (95%) was found to be a more sensitive marker than either HMB-45 (80%) or MART-1 (70%) for recognizing ALM. Melanin bleaching was useful for recognizing heavily pigmented ALM using both S-100 protein and HMB-45. The intensity of HMB-45 correlated well with the melanin content. However, there was no significant correlation between the intensity of S-100 protein and the melanin content. One and two out of 20 cases stained focally with EMA and CAM5.2, respectively, but these cases stained also with HMB-45 and/or S-100 protein. CONCLUSIONS: S-100 protein and HMB-45 were relatively sensitive markers for recognizing ALM. Despite the occasional positivity for the epithelial markers in ALM, all epithelial marker-positive cases stained also with HMB-45 and/or S-100 protein. Therefore, we recommend that the panel of antibodies used for recognizing ALM should contain at least S-100 protein and HMB-45.
BACKGROUND: Though acral lentiginous melanoma (ALM) is a major type of malignant melanoma, no immunohistochemical study on this type of melanoma has been reported. OBJECTIVE: The purpose of this study is to analysis the immunohistochemical findings of ALM using routinely used immune markers. METHODS: An immunohistochemical study was performed on paraffin sections of 20 ALMs using S-100 protein, HMB-45, MART-1, vimentin, epithelial membrane antigen (EMA) and CAM 5.2. RESULTS:S-100 protein (95%) was found to be a more sensitive marker than either HMB-45 (80%) or MART-1 (70%) for recognizing ALM. Melanin bleaching was useful for recognizing heavily pigmented ALM using both S-100 protein and HMB-45. The intensity of HMB-45 correlated well with the melanin content. However, there was no significant correlation between the intensity of S-100 protein and the melanin content. One and two out of 20 cases stained focally with EMA and CAM5.2, respectively, but these cases stained also with HMB-45 and/or S-100 protein. CONCLUSIONS:S-100 protein and HMB-45 were relatively sensitive markers for recognizing ALM. Despite the occasional positivity for the epithelial markers in ALM, all epithelial marker-positive cases stained also with HMB-45 and/or S-100 protein. Therefore, we recommend that the panel of antibodies used for recognizing ALM should contain at least S-100 protein and HMB-45.
Authors: Danilo N Odashiro; Alexandre N Odashiro; Patrícia R Pereira; Katyanne Godeiro; Emilia Antecka; Sebastian Di Cesare; Miguel N Burnier Journal: Cancer Cell Int Date: 2006-11-24 Impact factor: 5.722