MART-1 recognizes a protein of 18 kDa, identified at MART-1 (Melanoma Antigen Recognized by T cells) (1). MART-1 is a useful addition to melanoma panels as it is apparently specific for melanocytic lesions (1,2). Studies have shown that MART-1 is more sensitive than HMB45 when labeling metastatic melanomas (3). This MART-1 cocktail does not stain steroid tumors like Melan A  does. Tyrosinase has been shown a more sensitive marker in recognizing melanoma when compared to HMB45 and MART-1. It has also been shown to label a higher percentage of desmoplastic melanomas than HMB45 (1). The combination of MART-1 and Tyrosinase aids in identifying metastatic melanoma in sentinel lymph nodes (4).
Microscopic evaluation of mitotic figures on H&E is a routine procedure in the assessment of the tumor grades (5). However, the counting of mitosis is manual and time consuming with assorted difficulties as well as variabilities between interobserver assessments (6). Histone H3 phosphorylation at Serine10 (pHH3) is in association with mitotic chromatin condensation in late G2 and M phase of the cell cycle. pHH3 can distinguish mitosis from apoptotic nuclei (7). The immunohistochemical staining of Serine10-pHH3 has been reported to be comparable to mitotic figures in the H&E section (8-11). The combination of monoclonal anti-pHH3 with MART-1 and Tyrosinase would offer an advantage of specific epitopes for melanoma diagnosis and mitosis counting.
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