Which markers are included in the Pan-Mel Ki-67 panel?

• A. Tyrosinase -T311 Malignant melanoma- cyto; MART-1 Malignant Melanoma-Cyto; Ki-67 Proliferating cells-nuclear
• B. Tyrosinase, S100, Ki-67
• C. MART-1, S100, Ki-67
• D. Tyrosinase, MART-1, p53

Answer: (A)

Pan-Mel Ki-67 focuses on confirming melanocytic origin while also assessing how actively the tumor is proliferating. Tyrosinase and MART-1 (Melan-A) are both melanocytic lineage markers. They stain the cytoplasm of melanoma cells, helping to verify that the cells are of melanocytic origin. Ki-67, on the other hand, is a nuclear protein present in cells that are actively cycling, so staining for Ki-67 gives a proliferation index that informs about tumor growth and aggressiveness.

Putting these together—two melanocytic markers to establish lineage and Ki-67 to measure proliferation—creates a panel tailored for melanoma assessment. S100 is a melanocytic marker but is more broadly sensitive and less specific in some contexts, and p53 is a tumor suppressor not specific to melanoma lineage or proliferation assessment in this panel. Hence Tyrosinase, MART-1, and Ki-67 form the Pan-Mel Ki-67 combination.