Final answer:
Melanoma stains positive for S100 while Paget's disease stains positive for cytokeratin.
Step-by-step explanation:
The correct answer is A) Melanoma stains positive for S100, while Paget's disease stains positive for cytokeratin.
Staining is a technique used in pathology to identify specific molecules or structures in tissue samples. Melanoma is a type of skin cancer that arises from melanocytes, the cells responsible for producing the pigment melanin. Melanoma stains positive for S100, a protein marker that is commonly used to identify melanocytic tumors.
Paget's disease of the breast is a type of breast cancer that affects the cells of the nipple and areola. It typically presents with eczema-like changes on the nipple and is often associated with an underlying breast carcinoma. Paget's disease of the breast stains positive for cytokeratin, a protein marker that is used to identify epithelial cells, such as those found in breast tissue.