This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Integrated QBank, Subject name: Unknown
[{'content': 'A 50-year-old fair skinned male presented to the OPD with elevated plaque and ulcerated hyperpigmented nodule which shows variegation of colour on the back which has been progressively increasing in size. Biopsy of the skin lesion was done. All of the following antibodies can be tested except: - \nSelect and explain. \nA. Anti S100 Ab, B. Anti HMB45 Ab, C. Anti MA-1 Ab, D. Anti-Cytokeratin Ab', 'role': 'user'}, {'content': 'Answer: D \nExplanation: This is a case of superficial spreading melanoma. HPE image shows: - In the epidermis - malignant melanocytes huddling together to form loosely rounded structures called "nests". Singular melanocytes migrating upwards through the epidermis - a pattern known as a "pagetoid spread". Three antibodies can be tested: - A. Anti S100 Ab B. Anti HMB45 Ab C. Anti MA-1 Ab', 'role': 'assistant'}]