This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiration, Subject name: Pathology
Following is tumor marker for lung? 
Select and explain. 
A. S-100, B. CEA, C. CD-99, D. Beta 2 microgobulin
B: CEA
Answer: B: CEA 
Explanation: Ans is 'b' i.e. CEAImportant tumor markersTumor MarkersCancerHormones * Human chorionic gonadotropin* Gestational trophoblastic disease, gonadal germ cell tumor* Calcitonin* Medullary cancer of the thyroid* Catecholamines* Pheochromocytoma* Gastrin* Gastrinoma (pancreatic neuroendocrine tumor)Oncofetal Antigens * Alphafetoprotein* Hepatocellular carcinoma, gonadal germ cell tumor* Carcinoembryonic antigen* Adenocarcinomas of the colon, pancreas, lung, breast, ovaryEnzvmes * Prostatic acid phosphatase* Prostate cancer* Neuron-specific enolase & chromogranin A* Small cell cancer of the lung, neuroblastoma* Lactate dehydrogenase* Lymphoma, Ewings sarcomaTumor Associated Proteins * Prostatic-specific antigen* Prostate cancer* Monoclonal immunoglobulin* Myeloma* CA - 125* Ovarian cancer* CA 19-9* Colon, pancreatic, breast cancer* CA - 15-3* Breast cancer* CA 72-4* Ovarian, pancreatic & gastric Ca.* CA 27.29 &CA 15-3* Breast cancer* CD 30* Hodgkins disease, anaplastic large cell lymphoma* CD 25* Hairy cell leukemia, adult T cell leukemia / lymphoma* CD-34* Alveolar soft part sarcoma* b2- Microglobulin* Multiple myeloma* S-100, HMB-45, TA-90* Malignant melanoma* NMP-22* Urinary bladder Ca* CD-99* Ewing's sarcoma