Malignant mesothelioma (case 13). Cellular effusion with total predominance of malignant cells, all with strong nuclear fluorescence in telomere repeat amplification protocol (TRAP) in situ. TRAP estimate “high.” TRAP assay based on whole cell lysate TRAP relative telomerase activity of 72.7. a, Air-dried, Giemsa-stained Cytospin (original magnification ×200). b, Predominance of cytokeratin 5–positive, malignant mesothelial cells (ethanol-fixed cytospins, alkaline phosphatase anti-alkaline phosphatase, original magnification ×400). c, TRAP in situ. Strongly positive malignant nuclei (original magnification ×400).  Figure 2. Malignant mesothelioma (case 12). Cellular effusion with macrophages, lymphocytes, neutrophils, and approximately 20% malignant cells, all with strong nuclear fluorescence in telomere repeat amplification protocol (TRAP) in situ. TRAP estimate “medium.” TRAP assay based on whole cell lysate TRAP relative telomerase activity of 53.5. a, Air-dried, Giemsa-stained Cytospin (original magnification ×200). b, Cytokeratin 5–positive mesothelioma cells, against a background of macrophages (ethanol-fixed cytospins, alkaline phosphatase anti-alkaline phosphatase, original magnification ×400). c, TRAP in situ. Strongly positive malignant nuclei (original magnification ×400).