Heterogenous S-100B protein expression patterns in malignant melanoma and association with serum protein levels.
OBJECTIVE
Serum S-100B is a reliable tumor marker of malignant melanoma, but efficient use is restricted to patients with metastatic disease. Therefore, the aim of our study was to assess serum S-100B levels at different stages of malignant melanoma and to compare these levels with the expression of the S-100B phenotype in primary tumors and lymph node metastases.


METHODS
Fifty-nine patients were included in this study; serum S-100B protein was measured using an immunoluminometric assay while the expression pattern in the primary tumor was determined by immunohistochemistry using an anti-S-100B monoclonal antibody.


RESULTS
Serum S-100B concentrations were significantly elevated in stage III (p = 0.01) patients, with normal levels in stage I-II. The most frequent S-100B protein expression pattern of the melanoma tissue was found to be diffuse staining observed in around half of the cases (52.5%) followed by heterogeneous (30.5%) and focal patterns (17%), being independent of the stage as well as the lymph node involvement. In stage I-II patients, the various staining patterns did not correlate with the serum concentration of the S-100B protein, while in stage III patients with heterogenous or diffuse S-100B staining patterns in tumor tissue, the serum marker concentration was significantly higher (p < 0.05) than in patients with focal staining. Furthermore, S-100B staining of the melanoma tissue also differed (low/negative, medium and strong staining), and serum marker concentrations corresponded to the pattern of the staining intensity. In stage I-II, only strong staining was associated with elevated serum S-100B concentrations while in stage III medium and strong staining was found to be associated with significantly higher serum marker concentrations compared to patients with tumors with low/negative staining (p < 0.05).


CONCLUSIONS
In malignant melanoma characterized by focal and/or low S-100B staining in the tumor tissue determined by immunohistochemistry, S-100B monitoring in the serum may not suffice to detect disease progression.
Bánfalvi
T
T
Department of Dermatology, National Institute of Oncology, Budapest, Hungary.
Udvarhelyi
N
N
Orosz
Z
Z
Gergye
M
M
Gilde
K
K
Tímár
J
J
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D000911:Antibodies, Monoclonal; D014408:Biomarkers, Tumor / Q000032:analysis* / Q000097:blood* / Q000276:immunology; D018450:Disease Progression; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D008163:Luminescent Measurements; D008207:Lymphatic Metastasis; D008297:Male; D008545:Melanoma / Q000097:blood / Q000378:metabolism* / Q000556:secondary*; D008875:Middle Aged; D009367:Neoplasm Staging; D009414:Nerve Growth Factors; D011237:Predictive Value of Tests; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins / Q000032:analysis* / Q000097:blood* / Q000276:immunology; D012878:Skin Neoplasms / Q000097:blood / Q000378:metabolism* / Q000473:pathology*
D000911:Antibodies, Monoclonal; D014408:Biomarkers, Tumor; D009414:Nerve Growth Factors; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins