[Quantitative study of calcitonin gene methylation in myelodysplastic syndromes]

To investigate the role of calcitonin gene hypermethylation in the transformation from myelodysplastic syndromes (MDS) to acute myeloid leukemias (AML).

The methylation rate of calcitonin gene (CTMR) in the genomic DNA extracted from bone marrow cell of 27 MDS patients and 6 AML patients with antecedent MDS were studied by PCR amplification of Hpa I digested DNA, with external reference of undigested and Msp I digested DNA and internal reference of 112bp fragment containing N-ras-61. Intensity of silver-stained PCR products was measured by densitometer and analysed using the computer program.

The CTMR was significantly higher in MDS (33.65% +/- 23.37%) than in control group (P<0.001), in 9 RAEB(T) (58.35% +/- 17.44%) than in the control and RA groups. Five RA patients who have survived three to ten years without leukemia, have a normal CTMR. Seven of 8 RAEB(T) patients who had a high CTMR of more than 30% evolved into AML in two months.

CTMR might be a useful marker for predicting the evolution of MDS into AML.