This is an observational, non-interventional, multicenter study for the prospective collection, storage and analysis of patients' biological samples.

This study establishes a common international infrastructure useful to collect standard clinical variables at baseline and during treatment and to uniformly collect and store biological samples

Inclusion Criteria:

• Subjects with MGUS, smouldering Multiple Myeloma (SMM) , MM (Multiple Myeloma) (+/- EMD), plasma cell leukemia (PCL) (+/- EMD)

• Subjects are ≥ 18 years old.

• Subjects have provided written informed consent in accordance with federal, local, and institutional guidelines prior to initiation of any project-specific activities or procedures.

  1. Subjects do not have kind of condition that, in the opinion of the Investigators, may compromise the ability of the subjects to give written informed consent and
  2. subjects are, in the investigator's opinion, willing and able to comply with the protocol requirements.

Exclusion Criteria:

• Previous treatment with anti-myeloma therapy (excluding one course of therapy in patients in which urgent therapy is deemed necessary according to physician's discretion, e.g. myeloma-related complications resistant to supportive care).
• Subjects have had prior unforeseen (serious) adverse reactions to blood donation including, but not limited to fainting, angina, severe bruising, allergic reactions, or any other adverse events.
• Any psychological, familial, sociological and geographical condition potentially hampering compliance with the protocol and follow-up schedule.

Patients in hospitals in countries that participate in European Myeloma Network (EMN) trials; these patients may be included in upfront trials or in maintenance or relapse trials later during their disease.