The document discusses the use of diagnostic algorithms and antibody panels to identify tumor types through immunohistochemistry (IHC). It provides examples of algorithms that use sequential testing of antibodies to differentiate between common tumor types like carcinoma vs sarcoma, or to identify the primary origin of a metastatic tumor. The algorithms aim to increase diagnostic accuracy and guide treatment by narrowing down the possible tumor types. Key details about specific antibodies, their targets, and staining patterns are also presented.

3. Special stain vs IHC MUC-1 PAS MUC-1(IHC) PAS (Special Stain) AdenoCarcinoma (GI)

5. Basic Flow Chart Sequential First Round (+) ( - ) (+) (+) (+) ( - ) ( - ) ( - ) Second round

6. Use of Panel of Antibodies Ab1 Ab2 Ab3 Ab4 Ab5 Ab6 + (-) + (-) + + Tumor-1 (-) + (-) + (-) (-) Tumor-2

8. Diagnostic Algorithm for unknown Tumor Type Source adopted from: DAKO training manual Positive Positive Negative Negative Vimentin Positive Negative Negative Negative Desmin Negative Positive Negative Negative S 100 / HMB45/ MART-1 Tyrosinase Negative Negative Positive Negative LCA For Poorly differentiated malignant tumor differentiation Caution: Variation in cellular pattern can mislead (+) and (-) . Negative Negative Negative Positive Pan Keratin Notes Sarcoma Melanoma Lymphoma Carcinoma

9. Undifferentiated Malignant Neoplasm Almost always positive Almost always Negative Sometimes positive Sometimes negative Gowen AM.Diagnostic Immunohistochemistry of Solid Tumors: Strategies and Solutions,USCAP;2002 #35 CD43 PD7/2B11 CD 45 HMB 45 Melanoma antigen V9 Vimentin AE1/AE3 Cytokeratin Sarcoma Melanoma Lymphoma Carcinoma Abs/clone Abs to

11. Threshold for Positivity * Positive Generally : unequivocal staining of =10% of tumor cells +/- + -/+ (-) : >90% of tumors positive* : 50-90% of tumors positive* : 10-50% of tumors positive* : <10% of tumors positive* ? : Insufficient evidence [ ] : Staining of secondary (non-neoplastic) cell type ( ) : Staining dependant on antibody

12. Metastatic Adenocarcinoma of unknown origin with site specific markers PSA + (-) (-) (-) (-) (-) (-) (-) (-) + + + + + + + Prostate Lung Stomach/ Pancreas Breast Colon Colon Stomach / Pancreas Breast Ovary Pancreas ,(Ovary serous) Stomach / Pancreas Breast / Stomach / Pancreas Source: www.clincancerres.aacrjournals.org/egi/content/full/11/10/3766 TTF-1 GCDFP15 CDX2 / CK20 ER CA125 Mesothelin Lysozyme + + + (-) (-) (-) CDX2 CK 7 Mesothelin MC5+ (98%)

13. Details of Abs used in the Algorithm Dennis JL et al.Clinical Cancer Research;11:3766-3772,2005 HIER 1:500 DAKO Ks20.8 CK20 HIER 1:50 Novocastro SPT249 TTF-1 HIER 1:100 DAKO ER-PR8 PSA HIER 1:20 Novocastro 5B2 MESOTHELIN ENZYMATIC 1:5000 Novocastro POLY LYSOZOME HIER 1:20 Novocastro 23A3 GCDFP-15 HIER 1:50 Novocastro 6F11 ER HIER 1:500 DAKO OV-TL CK7 HIER 1:100 Novocastro AMT28 CDX2 HIER 1:400 Novocastro Ov185:1 CA 125 A R Dilution Source Clone Abs

14. Algorithm for Tumors of Unknown Origin Gross Cystic Disease Fluid Protein Source:www.clincancerres.aacrjournals.org/content/vol11/issue10 96 72 Stomach and Pancreas CK7 69 65 Stomach and Pancreas Lysozyme 85 85 Ovary and Pancreas Mesothelin 88 88 Ovary and Pancreas CA 125 95 74 Breast and Ovary ER 96 54 Breast GCDFP-15 97 36 Colon,Stomach, Pancreas CK20 91 68 Colon CK20 98 56 Colon and Stomach CDX-2 96 83 Colon CDX-2 98 91 Lung TTF-1 99 100 Prostate PSA % Specificity % Sensitivity Tumor of Marker

15. Differential Diagnosis Bladder vs Prostate ca Goldstein N.Immunohistochemical Antibody Panels to help Identify the Primary Sites of Various Carcinomas;ASCP Teleconference # 2109 + (-) PSA + (-) PAP (-) + CEA (-) + Cytokeratin 20 (-) + Cytokeratin 7

16. Mesothelioma or Small Cell Carcinoma ?

17. Mesothelioma vs Carcinoma Brown RW et al.Multiple-marker immunohistochemical phenotypes distinguishing malignant pleural mesothelioma from pulmonary adenocarcinoma. Hum Pathol.1993;24:347-354 70 0 B72.3 30 90 Calretinin 80 0 Ber-EP4 30 40 Vimentin 65 0 Placental Alkaline Phosphatase 15 0 CEA 85 10 S-100 75 10 Leu-M1 8 100 Thrombomodulin 100 80 EMA 100 100 Cytokeratin Carcinoma % Mesothelioma % Antigen

24. A, Normal post-menopausal endometrium (H&E, 20x); B, MUC1 immunostain in normal postmenopausal endometrium showing “pure apical” staining pattern (x20); C, normal endocervical glands (H&E, 20x); D, MUC1 immunostain in normal endocervical glands showing A/C staining pattern, (x20). MUC1-Purely Apical vs Apical & Cytoplasmic Khoury T, et al.BMC Clin Pathol.2006;6:1