**7. Conclusion**

CD56-

. Moreover, the cytogenetic analysis of this case

evolution of monoclonal component, the risk of progression was better described by immu‐ nophenotypisation [71]. Multiparametric FC is thus capable to distinguish patients which need more frequent monitoring and which need to start treatment earlier than usual. There is still not any marker allowing discrimination between benign MGUS and its malignant form at this

Determination of immunophenotype should be used not only for discrimination of normal and pathological PCs, but it has also prognostic value. The loss of CD56 (neural cell adhesion molecule, NCAM) should be joined with extramedullary spread [72]. An association between the phenotype profile and cytogenetic abnormalities was found. Expression of CD19 and CD28 and/or absence of the CD117 on pathological PCs are joined with significantly shorter time without progression and overall survival in transplanted patients [46]. Expression of CD28 correlated with t(14;16) and del(17p), on the other hand no presence of CD117 was joined with t(4;14) and del(13q). The analysis combining both CD28 and CD117 was able to divide patients into 3 risk groups with different time without progression and overall survival. The correlation of CD117 expression with hyperdiploidy was found as well [73]. The expression of CD117 on PCs is associated with changes in production of haematopoietic stem cells from BM, lead to a decreasing number of neutrophils in PB and the presence of normal PCs in BM [57]. Recently, a rare MM case was described with PCs phenotype: CD19+

revealed a hyperdiploid karyotype and no rearrangement of the IgH gene or deletion of 13q14 [74]. The very important genetic change in MM is loss of the gene for CD27 which is linked with clinically aggressive disease, but in about 50% of MM is expression of CD27 preserved and these patients have better prognosis [44]. Probably the best prognostic information until now serves a combination of two independent parameters: the presence of high-risk cytoge‐ netics by FISH and persistent minimal residual disease evaluated by multiparameter flow cytometry at day +100 after autologous transplantation. These two parameters were able to identify patients in complete remission at risk of early progression [75]. The important thing is that these two methods are available in most hospitals taking care of patients with haema‐

It is known that conventional parameters (% PCs, MIG level) are not sensitive enough for analysis of treatment response in MM patients. As FC is applicable up to 80-90% of patients, this method is able to reach the sensitivity of allelic-specific oligonucleotide (ASO)-PCR (sensitivity 10-4 for FC vs. 10-5 for PCR) and is less time and monetary consuming as well. Hence FC looks as the optimal method for minimal residual disease (MRD) assessment after any treatment [76,77]. The advantage of FC in MRD analysis is the versatility of used markers allowing assessment of normal and abnormal PCs (CD19/CD56), removing the need to know the original phenotype of PCs before treatment. MRD negativity proved by FC (detection <10-4 myeloma PC within all nucleated cells) was more informative then

moment.

CD20+

CD22+

tological malignancies.

**6.4. Minimal residual disease analysis**

CD28+

CD33+

CD117+

HLA-DR+

**6.3. Prognostic markers in MGs**

102 Multiple Myeloma - A Quick Reflection on the Fast Progress

Flow cytometry analysis was performed only in a limited number of subjects with monoclonal gammopathies in the late 1990's and early 2000's. During the past decade and present, many analyses showed importance of MFC in differential diagnostics and monitoring (management) of plasma cell diseases. The MFC has developed significantly and with better understanding of PC pathophysiology is the mandatory diagnostic tool which should be included as a routine assay in monoclonal gammopathy patients.
