What is the reported sensitivity range for ALP staining in detecting osteosarcoma?

• A. 50-70%
• B. 88-100%
• C. 10-30%
• D. 100%

Answer: (B)

Alkaline phosphatase staining is used because osteoblasts and osteogenic tumor cells commonly produce this enzyme. In osteosarcoma, many neoplastic cells show ALP activity, so the stain tends to be positive in most cases. The reported sensitivity is high, around 88–100%, which means ALP staining will detect the vast majority of osteosarcomas, though a minority may be ALP-negative in poorly differentiated or necrotic tumors. This is why that high range is the best fit: it reflects the commonly observed efficacy of ALP staining in identifying osteogenic tumors. Lower ranges like 50–70% or 10–30% would underestimate its usefulness, and a perfect 100% is unlikely due to occasional false negatives.