A NEW MULTIPLE MYELOMA CLASSIFICATION SYSTEM THAT CORRELATES TO DISEASE STAGE AND PROGNOSIS - INDICATION OF REVERSIBLE PHENOTYPIC PLASTICITY AS A HALLMARK
(Abstract release date: 05/19/16)
EHA Library. Johnsen H. 06/11/16; 135204; S448
Prof. Hans Erik Johnsen
Contributions
Contributions
Abstract
Abstract: S448
Type: Oral Presentation
Presentation during EHA21: On Saturday, June 11, 2016 from 11:45 - 12:00
Location: Auditorium 2
Background
Today’s diagnostic tests for multiple myeloma (MM) reflect the criteria of the updated WHO classification based on biomarkers and clinicopathologic heterogeneity.
Aims
To that end, we propose a new biological subtyping of myeloma plasma cells (mPC) by B-cell subset associated gene signatures (BAGS), from the normal B-cell hierarchy in the bone marrow (BM). Here we document the prognostic and biological value of subtyping, as shown for DLBCL (JCO 2015 Apr 20; 33:1379).
Methods
We combined FACS and GEP to generate BAGS classifiers for the normal BM subsets: PreB-I, PreB-II, immature (Im), naive (N), memory (M) and PC. Construction was based on median-centred probe sets from the BM data using regularized multinomial regression with six discrete outcomes representing BAGS, by a total of 55 genes varying from 15-24 per subtype. Each patient underwent BAGS assignment according to the highest predicted probability score above 0.45 or was otherwise unclassified.The impact of BAGS was analyzed using six clinical cohorts, gathered across geographical regions, time eras, and sampling methods. The analysis estimated subtype frequencies and included a prognostic meta-analysis of 926 patients treated with high dose melphalan as first line therapy in 3 prospective trials: UAMS, HOVON65/GMMG-HD4, MRC Myeloma IX data with the Affymetrix U133 plus 2.0 microarray data available from myeloma PC samples. To compensate for cohort-wise technical batch effects, each cohort was median centred and adjusted probe set-wise to have same variance as the BM data.
Results
Validation of the normal B-cell subset phenotypesNormalized histograms of the fluorescence intensities (FI) of CD markers based on merged multiparametric flow cytometry reanalysis of pure sorted populations resulting from seven independent sorting procedures documented high purity. Principal component analysis (PCA) of the FI for each sorted cell in all samples documented specificity. Surface markers, transcription factors, and B-cell differentiation–specific genes were identified through a literature review, and their expression across subsets was evaluated. The most varying probe sets were included in an unsupervised hierarchical clustering analysis, supporting the biological differences.Validation of MM patients subtyping by prognosis The resultant tumor assignments exhibited very similar BAGS subtype frequencies, across 1302 individual MM cases from 4 different cohorts. The 5 BAGS subtypes of 926 MM cases were significantly associated with overall (P=5.2x10-8) and progression free (P=1.5x10-6) survival in a meta-analysis of patients in the 3 clinical trials. The major impact was observed within the PreB-II and M subtypes conferred with significant increased ISS stage III and inferior prognosis compared to the Im, N and PC subtypes.Cox proportional hazard meta-analysis showed that the five BAGS subtypes added significant and independent prognostic information to the TC classification system and plasma Beta-2 microglobulin level. In parallel we found significant correlation between the PreBII subtypes and the proliferation index, risk profiling (P<0.0001) and Beta-2 microglobulin (P<0.001).
Conclusion
We have documented patient specific mPC differences with prognostic impact in support of reversible phenotypic plasticity in MM. This observation provides a new model for generating insight into the stages of clonal plasticity associated with oncogenesis and dedifferentiation.
Session topic: New biological markers in MM
Keyword(s): Multiple myeloma, Phenotype, Prognostic groups
Type: Oral Presentation
Presentation during EHA21: On Saturday, June 11, 2016 from 11:45 - 12:00
Location: Auditorium 2
Background
Today’s diagnostic tests for multiple myeloma (MM) reflect the criteria of the updated WHO classification based on biomarkers and clinicopathologic heterogeneity.
Aims
To that end, we propose a new biological subtyping of myeloma plasma cells (mPC) by B-cell subset associated gene signatures (BAGS), from the normal B-cell hierarchy in the bone marrow (BM). Here we document the prognostic and biological value of subtyping, as shown for DLBCL (JCO 2015 Apr 20; 33:1379).
Methods
We combined FACS and GEP to generate BAGS classifiers for the normal BM subsets: PreB-I, PreB-II, immature (Im), naive (N), memory (M) and PC. Construction was based on median-centred probe sets from the BM data using regularized multinomial regression with six discrete outcomes representing BAGS, by a total of 55 genes varying from 15-24 per subtype. Each patient underwent BAGS assignment according to the highest predicted probability score above 0.45 or was otherwise unclassified.The impact of BAGS was analyzed using six clinical cohorts, gathered across geographical regions, time eras, and sampling methods. The analysis estimated subtype frequencies and included a prognostic meta-analysis of 926 patients treated with high dose melphalan as first line therapy in 3 prospective trials: UAMS, HOVON65/GMMG-HD4, MRC Myeloma IX data with the Affymetrix U133 plus 2.0 microarray data available from myeloma PC samples. To compensate for cohort-wise technical batch effects, each cohort was median centred and adjusted probe set-wise to have same variance as the BM data.
Results
Validation of the normal B-cell subset phenotypesNormalized histograms of the fluorescence intensities (FI) of CD markers based on merged multiparametric flow cytometry reanalysis of pure sorted populations resulting from seven independent sorting procedures documented high purity. Principal component analysis (PCA) of the FI for each sorted cell in all samples documented specificity. Surface markers, transcription factors, and B-cell differentiation–specific genes were identified through a literature review, and their expression across subsets was evaluated. The most varying probe sets were included in an unsupervised hierarchical clustering analysis, supporting the biological differences.Validation of MM patients subtyping by prognosis The resultant tumor assignments exhibited very similar BAGS subtype frequencies, across 1302 individual MM cases from 4 different cohorts. The 5 BAGS subtypes of 926 MM cases were significantly associated with overall (P=5.2x10-8) and progression free (P=1.5x10-6) survival in a meta-analysis of patients in the 3 clinical trials. The major impact was observed within the PreB-II and M subtypes conferred with significant increased ISS stage III and inferior prognosis compared to the Im, N and PC subtypes.Cox proportional hazard meta-analysis showed that the five BAGS subtypes added significant and independent prognostic information to the TC classification system and plasma Beta-2 microglobulin level. In parallel we found significant correlation between the PreBII subtypes and the proliferation index, risk profiling (P<0.0001) and Beta-2 microglobulin (P<0.001).
Conclusion
We have documented patient specific mPC differences with prognostic impact in support of reversible phenotypic plasticity in MM. This observation provides a new model for generating insight into the stages of clonal plasticity associated with oncogenesis and dedifferentiation.
Session topic: New biological markers in MM
Keyword(s): Multiple myeloma, Phenotype, Prognostic groups
Abstract: S448
Type: Oral Presentation
Presentation during EHA21: On Saturday, June 11, 2016 from 11:45 - 12:00
Location: Auditorium 2
Background
Today’s diagnostic tests for multiple myeloma (MM) reflect the criteria of the updated WHO classification based on biomarkers and clinicopathologic heterogeneity.
Aims
To that end, we propose a new biological subtyping of myeloma plasma cells (mPC) by B-cell subset associated gene signatures (BAGS), from the normal B-cell hierarchy in the bone marrow (BM). Here we document the prognostic and biological value of subtyping, as shown for DLBCL (JCO 2015 Apr 20; 33:1379).
Methods
We combined FACS and GEP to generate BAGS classifiers for the normal BM subsets: PreB-I, PreB-II, immature (Im), naive (N), memory (M) and PC. Construction was based on median-centred probe sets from the BM data using regularized multinomial regression with six discrete outcomes representing BAGS, by a total of 55 genes varying from 15-24 per subtype. Each patient underwent BAGS assignment according to the highest predicted probability score above 0.45 or was otherwise unclassified.The impact of BAGS was analyzed using six clinical cohorts, gathered across geographical regions, time eras, and sampling methods. The analysis estimated subtype frequencies and included a prognostic meta-analysis of 926 patients treated with high dose melphalan as first line therapy in 3 prospective trials: UAMS, HOVON65/GMMG-HD4, MRC Myeloma IX data with the Affymetrix U133 plus 2.0 microarray data available from myeloma PC samples. To compensate for cohort-wise technical batch effects, each cohort was median centred and adjusted probe set-wise to have same variance as the BM data.
Results
Validation of the normal B-cell subset phenotypesNormalized histograms of the fluorescence intensities (FI) of CD markers based on merged multiparametric flow cytometry reanalysis of pure sorted populations resulting from seven independent sorting procedures documented high purity. Principal component analysis (PCA) of the FI for each sorted cell in all samples documented specificity. Surface markers, transcription factors, and B-cell differentiation–specific genes were identified through a literature review, and their expression across subsets was evaluated. The most varying probe sets were included in an unsupervised hierarchical clustering analysis, supporting the biological differences.Validation of MM patients subtyping by prognosis The resultant tumor assignments exhibited very similar BAGS subtype frequencies, across 1302 individual MM cases from 4 different cohorts. The 5 BAGS subtypes of 926 MM cases were significantly associated with overall (P=5.2x10-8) and progression free (P=1.5x10-6) survival in a meta-analysis of patients in the 3 clinical trials. The major impact was observed within the PreB-II and M subtypes conferred with significant increased ISS stage III and inferior prognosis compared to the Im, N and PC subtypes.Cox proportional hazard meta-analysis showed that the five BAGS subtypes added significant and independent prognostic information to the TC classification system and plasma Beta-2 microglobulin level. In parallel we found significant correlation between the PreBII subtypes and the proliferation index, risk profiling (P<0.0001) and Beta-2 microglobulin (P<0.001).
Conclusion
We have documented patient specific mPC differences with prognostic impact in support of reversible phenotypic plasticity in MM. This observation provides a new model for generating insight into the stages of clonal plasticity associated with oncogenesis and dedifferentiation.
Session topic: New biological markers in MM
Keyword(s): Multiple myeloma, Phenotype, Prognostic groups
Type: Oral Presentation
Presentation during EHA21: On Saturday, June 11, 2016 from 11:45 - 12:00
Location: Auditorium 2
Background
Today’s diagnostic tests for multiple myeloma (MM) reflect the criteria of the updated WHO classification based on biomarkers and clinicopathologic heterogeneity.
Aims
To that end, we propose a new biological subtyping of myeloma plasma cells (mPC) by B-cell subset associated gene signatures (BAGS), from the normal B-cell hierarchy in the bone marrow (BM). Here we document the prognostic and biological value of subtyping, as shown for DLBCL (JCO 2015 Apr 20; 33:1379).
Methods
We combined FACS and GEP to generate BAGS classifiers for the normal BM subsets: PreB-I, PreB-II, immature (Im), naive (N), memory (M) and PC. Construction was based on median-centred probe sets from the BM data using regularized multinomial regression with six discrete outcomes representing BAGS, by a total of 55 genes varying from 15-24 per subtype. Each patient underwent BAGS assignment according to the highest predicted probability score above 0.45 or was otherwise unclassified.The impact of BAGS was analyzed using six clinical cohorts, gathered across geographical regions, time eras, and sampling methods. The analysis estimated subtype frequencies and included a prognostic meta-analysis of 926 patients treated with high dose melphalan as first line therapy in 3 prospective trials: UAMS, HOVON65/GMMG-HD4, MRC Myeloma IX data with the Affymetrix U133 plus 2.0 microarray data available from myeloma PC samples. To compensate for cohort-wise technical batch effects, each cohort was median centred and adjusted probe set-wise to have same variance as the BM data.
Results
Validation of the normal B-cell subset phenotypesNormalized histograms of the fluorescence intensities (FI) of CD markers based on merged multiparametric flow cytometry reanalysis of pure sorted populations resulting from seven independent sorting procedures documented high purity. Principal component analysis (PCA) of the FI for each sorted cell in all samples documented specificity. Surface markers, transcription factors, and B-cell differentiation–specific genes were identified through a literature review, and their expression across subsets was evaluated. The most varying probe sets were included in an unsupervised hierarchical clustering analysis, supporting the biological differences.Validation of MM patients subtyping by prognosis The resultant tumor assignments exhibited very similar BAGS subtype frequencies, across 1302 individual MM cases from 4 different cohorts. The 5 BAGS subtypes of 926 MM cases were significantly associated with overall (P=5.2x10-8) and progression free (P=1.5x10-6) survival in a meta-analysis of patients in the 3 clinical trials. The major impact was observed within the PreB-II and M subtypes conferred with significant increased ISS stage III and inferior prognosis compared to the Im, N and PC subtypes.Cox proportional hazard meta-analysis showed that the five BAGS subtypes added significant and independent prognostic information to the TC classification system and plasma Beta-2 microglobulin level. In parallel we found significant correlation between the PreBII subtypes and the proliferation index, risk profiling (P<0.0001) and Beta-2 microglobulin (P<0.001).
Conclusion
We have documented patient specific mPC differences with prognostic impact in support of reversible phenotypic plasticity in MM. This observation provides a new model for generating insight into the stages of clonal plasticity associated with oncogenesis and dedifferentiation.
Session topic: New biological markers in MM
Keyword(s): Multiple myeloma, Phenotype, Prognostic groups
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