False. While S-100 protein is a very sensitive marker for melanocytes and is widely used in diagnosing melanoma, it is NOT highly specific. S-100 is a calcium-binding protein expressed in a wide variety of cell types beyond melanocytes. These include: 1) **Neural cells**: Schwann cells, glial cells, some neurons. 2) **Cartilage cells** (chondrocytes). 3) **Adipocytes**. 4) **Myoepithelial cells** of salivary and sweat glands. 5) **A subset of dendritic cells and lymphocytes**. Therefore, tumors derived from these cell types (e.g., schwannomas, gliomas, liposarcomas, myoepitheliomas) can also be S-100 positive. In diagnostic practice, S-100 is used as part of a panel with more specific melanocytic markers like MART-1 (Melan-A) and HMB-45 to confirm a diagnosis of melanoma. Relying on S-100 alone could lead to misdiagnosis, especially for poorly differentiated tumors.

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Zambia

• ivwananji siwale – 29 pts

• Visual Pathway Lesions
• Positive and Negative Symptoms
• Hallucinations and Delusions
• Antipsychotic Medications
• Emergency: Environmental Emergencies