Methylation profiling in multiple myeloma.
BACKGROUND
We analysed the methylation status of a panel of 10 genes including p15, p16, DAPK, p73, VHL, E-CAD, MGMT, RARbeta, RIZ1, and ER.


METHODS
The gene promoter methylation status was studied by methylation-specific polymerase chain reaction (MSP) with primers for methylated (M-MSP) and unmethylated (U-MSP) DNA in the bone marrow of 13 patients with myeloma, and one patient with plasmacytoma.


RESULTS
None of the 10 genes tested were methylated in eight normal bone marrow samples. For the positive control, the sensitivity of M-MSP ranged from 1 x 10(-2) for E-CAD and MGMT, to 1 x 10(-4) for p73. Of the eight diagnostic myeloma marrow samples, hypermethylation of p15, p16, E-CAD, DAPK and ER occurred in six (75%), four (50%), seven (87.5%), eight (100%), and six (75%) patients. Similarly, of the five samples from patients who progressed from plateau phase, hypermethylation of p15, p16, E-CAD, DAPK, and ER occurred in five (80%), two (40%), five (100%), five (100%), and three (60%). None of the cases had hypermethylation of RIZ1, p73, VHL, RARbeta, and MGMT. At diagnosis, all patients had concurrent hypermethylation of at least three genes, and five (62%) had concurrent methylation of four or more genes. One patient with plasmacytoma had methylation of E-CAD, ER, and DAPK.


CONCLUSIONS
p15, p16, ER, DAPK, and E-CAD (but not RARbeta, p73, VHL, RIZ1, and MGMT) were frequently methylated in MM at both diagnosis and disease progression. Future studies of larger scale are needed to identify the genes responsible for disease progression.
Chim
C S
CS
Department of Medicine, Queen Mary Hospital, University of Hong Kong, Hong Kong, PR China. jcschim@hkucc.hku.hk
Kwong
Y L
YL
Fung
T K
TK
Liang
R
R
D001483:Base Sequence; D019175:DNA Methylation; D017931:DNA Primers; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008969:Molecular Sequence Data; D009101:Multiple Myeloma / Q000235:genetics*; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic
D017931:DNA Primers