Plasma cell & other. People who have diagnosis of plasma cell disorders- called mgus ( monoclonal gammopathy of unknown significance) would be the one who is at risk for multiple myeloma. Other potential risk factors - include older age, male ( hormone related?), black/african american, exposures to radiation, benzene, and other organic solvents, herbicides, and insecticides and other unknown risk factors.
Unknown/MGUS. The exact cause of multiple myeloma is not known. Myeloma is almost always (?Always) preceded by monoclonal gammopathy of undetermined significance (mgus). Risks: age, male gender, black race; radiation, benzene/petroleum exposure. Laboratory studies can help predict risk of conversion from mgus to myeloma. Genome sequencing may help provide answers in populations and individuals.