Normal frequencies of the C677T genotypes on the methylenetetrahydrofolatereductase (MTHFR) gene among lymphoproliferative disorders but not in multiple myeloma

The folate availability seems to be critical for the DNA integrity since it is required for the transfer of methyl groups in the biosynthesis of thymi dilate. Although the excessive incorporation of uracils to the DNA can be e fficiently removed, this mechanism of reparation produces many double-stran d breaks from two opposing nicks, Several chromosomal abnormalities (mainly translocations and deletions perhaps not well understood) are involved in the origin of lymphoproliferative disorders. The TT homozygosity at nucleot ide 677 in the gene of methylene tetrahydrofolatereductase (MTHFR), a key e nzyme in folate metabolism was recently linked to a significant protection against colon carcinoma and acute lymphoblastic leukaemia in adults. We ana lysed the genotype frequencies of C677T-MTHFR in a group of 143 patients wi th lymphoproliferative disorders (REAL classification) and 200 controls. Ov erally, the frequencies of the polymorphic allele were similar (35.3% and 3 2.0% respectively)(P=0.6). We did not find differences between patients and controls except fur myeloma/plasmacytoma group (n=26) which showed a CC ge notype less than expected (19% vs 46%) (p=0.01) with a frequency ratio of 0 .28 (0.10-0.77). Even among the IgG myeloma cases only one patient showed a common genotype (CC) (1/15, 7%) (P=0.003). If these preliminary data are v alidated with prospective studies, the 677C allele of MTHFR gene could be c onfirmed as an effective multiple myeloma protective factor (specially for the IgG cases).