The following criteria is provided for health care professionals.

Inclusion Criteria:

1. Written Informed Consent provided by patient
2. MM, with the following conditions:

*For patients in the Vanguard cohort*

1. Treatment naïve disease with BM clinically indicated

*For patients in the RRMM cohort*

1. Relapsed/refractory disease with BM samples clinically indicated
2. Within 4-weeks prior to initiation of 2nd-line or later therapy
3. Proceeding onto one of the following combination therapies [bortezomib (V), carfilzomib (K), lenalidomide (R), pomalidomide (P), cyclophosphamide (C), dexamethasone (d), ixazomib (I)]: RVd, VCd, KRd, PVd, KPd, Rd, Pd, Kd, IPd, IRd, RCd, PCd, venetoclax, Vd + venetoclax, Kd + venetoclax, selinexor+d

Exclusion Criteria:

1. Unable or unwilling to provide informed consent
2. Daratumumab/Elotuzumab or other antibody-based therapeutic regimens as immediately planned treatment (as prior therapy is acceptable)
3. Clinical trial with non-commercial relapsed/refractory samples as immediately planned treatment
4. Prior exposure to chimeric antigen receptor T-cell (CAR-T) therapy
5. Prior allogeneic stem cell transplant
6. Has received any systemic chemotherapy or radiation therapy (RT), including palliative, within 7 days prior to BM biopsy
7. Has received any Ab therapy within 4 weeks prior to BM biopsy