Final answer:
Proteins in a malignant pleural effusion from a patient with multiple myeloma would show elevated levels and abnormal patterns on an electrophoresis gel indicative of monoclonal proteins or M proteins. Diagnostic features include a distinct band in the gamma globulin region and skewed precipitin arcs in immunoelectrophoresis.
Step-by-step explanation:
Proteins in a malignant pleural effusion are often altered due to the presence of cancerous conditions such as multiple myeloma. Multiple myeloma is characterized by the production of abnormal antibodies known as monoclonal proteins or M proteins. These M proteins result in elevated serum protein levels and present diagnostic patterns on an electrophoresis gel, such as a distinct band in the gamma globulin region and a sharp spike on a densitometer scan, which are not observed in normal samples.
Immunoelectrophoresis (IEP) is a technique used to diagnose conditions like multiple myeloma by identifying these abnormal M proteins. In multiple myeloma, since the antibodies produced are abnormal and monoclonal, they form distinctly skewed precipitin arcs on an IEP gel when tested against anti-heavy chain and anti-light chain antibodies. These diagnostic features are indicative of the abnormal protein presence in pleural effusions associated with malignancies.