- Tissue specimens must be large enough in quantity to allow routine pathologic analysis, with the research laboratory specimen removed from the residual specimen, which would otherwise be discarded. Optimal tissue amounts for snap freeze: Core biopsy - 2 tissue cores Incisional biopsy- 0.5 to 1.5 grams Resected sarcoma specimen- 1.0 to 50 grams depending on size of specimen Normal fat or muscle tissue - 0.5 to 4.0 grams (if available from resected sarcoma specimen) Optimal tissue amounts for RNA later Core biopsy - 2 tissue cores Incisional biopsy- 30 mg (three 3 x 3 x 3 mm cubes) Resected sarcoma specimen - 30 mg (three 3 x 3 x 3 mm cubes) Normal fat or muscle tissue - 30 mg (three 3 x 3 x 3 mm cube