Methylation pattern of LRP15 gene in leukemia.

Objective: To investigate the methylation status of LRP15 gene in acute leukemia (AL) patients and its role in the tumorigenesis.

Methods: The methylation of LRP15 promoter and first exon of bone marrow mononuclear cells in 73 patients with AL, 10 with chronic leukemia (CL), 9 with hematological benign diseases, and 20 healthy transplantation donors was analyzed by using methylation specific polymerase chain reaction. The methylation of LRP15 gene promoter and first exon in COS7, K562, and HL60 cell lines was also assayed.

Results: No LRP15 gene promoter methylation was detected in COS7 cell line. LRP15 gene promoter was methylated in K562 and HL60 cell lines. No deletion of LRP15 gene was detected in all samples. In nearly all French-American-British leukemia subtypes, we found that frequency of LRP15 methylation in adult patients with AL was 71.23% (52/73). There was no detectable methylation in any of the 20 healthy donors and 8 chronic myeloid leukemia patients. The difference in frequency of LRP15 methylation between AL patients and healthy donors or CL patients (10.00%, 1/10) was significant (P < 0.01). Hypermethylation of LRP15 gene was found in 57.14% (16/28) of newly diagnosed AL patients, 83.33% of relapsed AL patients respectively, which was significantly different (P < 0.05). We also demonstrated LRP15 methylation in 55.56% (5/9) adults with benign hematological diseases.

Conclusions: LRP15 methylation changes are common abnormalities in leukemia. LRP15 is postulated to be a tumor suppressor gene.