Oral melanocytic lesions: differences in expression of HMB‐45 and S‐100 antigens in round and spindle cells of malignant and benign lesions

Abstract

Immunohistochemistry and melanin bleaching were used to assess the expression of antigens identified by anti-S-100 and anti-HMB-45 antibodies on melanomas and intramucosal and blue nevi from the oral mucosa of 18 patients. Both antibodies reacted with cells in all three types of lesions, but there were differences in the expression of these antigens between the round and spindle cells within the lesions. In melanomas composed of round cells, the intensity and distribution of staining with HMB-45 was greater than with S-100. The opposite was true in melanomas composed of spindle-shaped cells, and one spindle-cell melanoma was HMB-45-negative. The round cells of intramucosal nevi expressed S-100 more intensely and more frequently than HMB-45. The spindle-shaped cells of blue nevi strongly expressed both S-100 and HMB-45. Whereas intradermal nevi from the skin do not express HMB-45, intramucosal nevi consistently express this antigen in the lesion and overlying mucosa. Oral melanomas composed of round and spindle-shaped cells show differences in their expression of S-100 and HMB-45 antigens, making the use of both antibodies complementary in the diagnosis of undifferentiated tumors.

Plaque-Type Blue Nevus of the Oral Cavity

“…Our findings are in accordance with other authors who also found negative S-100 protein staining of blue nevi of the skin [22, 23], but in contrast to the results of Lovas et al [22] who found a positive S-100 staining in all of 5 examined intraoral blue nevi. Also Gazit and Daniels [24] found in all of 6 examined blue nevi of the oral mucosa a positive S-100 protein staining of the elongated spindle-shaped cells. HMB-45 is a monoclonal antibody that recognizes a premelanosomal glycoprotein.…”

Primary Oral Mucosal Melanomas – Two Case Reports and Comprehensive Literature Review

“…Protein S-100, besides helping in determining tumor thickness, has been shown in some studies to be of a potential prognostic value, i.e. the intensity of staining by protein S-100 was in reverse correlation with the survival time [31][32][33] . All these routinely and most frequently used antibodies in the histopathologic diagnosis of OM are used in cases of melanocytic diff erentiation of tumor cells, i.e.…”

A rare case of amelanotic malignant melanoma in the oral region: Clinical investigation and immunohistochemical study

“…Anti-S-100, anti-HMB-45 and anti-Melan-A are the three most commonly used antibodies for the immunohistochemical diagnosis of primary oral MM. Previous studies have recorded a positive rate of 100% for anti-S-100 (3,7,11) and ~79% (range, 71-100%) for anti-HMB-45 (1,3,7,11). These results indicated that S-100 is a more sensitive marker than HMB-45 and Melan-A for immunohistochemically diagnosing MM.…”

“…MMs are known to have a high potential for malignancy, invasiveness and metastasis (1,2). Although MMs with characteristic melanin-pigmented tumor cells are easy to diagnose, amelanotic MMs (AMMs) are extremely difficult to diagnosis due to the absence of these cells (3,4). AMM can be divided into the following five types based on the varied clinical features observed: The pigmented nodular type, the non-pigmented nodular type, the pigmented macular type, the pigmented mixed type and the non-pigmented mixed type (5,6).…”