This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Multiple Myeloma, Subject name: Pathology
Multiple myeloma most common part involved is- 
Select and explain. 
A. Bone marrow, B. Cortex of bone, C. Metaphyses, D. Epiphyses
A: Bone marrow
Answer: A: Bone marrow 
Explanation: Ans. is 'a' i.e., Bone marrow Multiple mveiomao Multiple myeloma is a plasma cell neoplasm characterized by involvement of the skeleton at multiple sites,o Plasma cells proliferate abnormally and the proliferated plasma cells infiltrate various organs, particularly bone marrow, but can also spread to lymph nodes and extranodal sites like skin,o The proliferation and survival of myeloma cells are dependent on several cytokines, IL-h Is particularly important.o The neoplastic plasma cells secrete abnormally large amounts of immunoglobulin.o The immunoglobulin secreted by neoplastic plasma cells are quiet different form the immunoglobulin normally present in the blood.o The normal immunoglobulin consists of two heavy and two lights chains molecules and the production of both chain is tightly balanced.o The immunoglobulin secreted in this condition may be : -Isolated light chain or heasy chain.May be an intact antibody molecule of any heavy chain subclass.May be an altered antibody or fragment.