Final answer:
An increase in plasma cells can be seen in a variety of nonmalignant disorders, such as multiple myeloma and various types of cancer.
Step-by-step explanation:
Plasma cells are a type of lymphocyte that produce soluble antibodies in response to antigen binding. An increase in plasma cells can be seen in various nonmalignant disorders such as multiple myeloma, pancreatic cancer, brain tumors, breast cancer, neuroblastoma, acute myeloid leukemia, non-Hodgkin's lymphoma, melanoma, non-small cell lung cancer, Hodgkin lymphoma, and bladder cancer.