Is multiple myeloma genetic?

Yes/No. In a sense all cancer is "genetic" involving changes to the DNA or epi-genetic - changes to DNA modifiers such as methylation. A related question is is multiple myeloma inherited. The answer is sometimes. The risk is about double with a family history. Here is one clinical trial studying this:
No. Myeloma does not appear to have a genetic predisposition.
Likely Not. There is no clear genetic predisposition in multiple myeloma. Rather, older age, immunosuppression, and environmental exposures to radiation, benzene, and other organic solvents, herbicides, and insecticides are potential risk factors for multiple myeloma.