BACKGROUND: The expression of the multidrug resistance-1 (MDR-1) gene which encodes p-glycoprotein, is recognized as a biological mechanism possibly contributing to treatment failure in patients with acute myeloid leukemia (AML). Recent studies indicate its association with poor risk factors such as cytogenetic pattern and surface phenotype of blasts. We analyzed the role of MDR-1 gene expression in 36 chemo-naive AML patients.
METHODS: In 36 patients, clinical data were reviewed and compared to MDR-1 gene expression, immunophenotyping results on CD7 ＆ CD34, cytogenetic pattern and other suggestive prognostic factors.
RESULTS: Median follow-up period was 150 days. The MDR-1 gene expression was observed in 19 out of 36 patients (52.8%). Significant correlation between MDR-1 gene and CD7 ＆ CD34 expression was found. Sixteen out of 17 (94.1%) MDR-1 negative patients harbored favorable cytogenetic patterns, where as 11 out of 19 (57.9%) MDR-1 positive patients had favorable cytogenetic patterns. MDR-1 gene expression was not correlated to disease free survival (DFS), nor overall survival (OS) statistically although it has shown significant correlation to complete remission (CR) rate (p=0.001).
CONCLUSION: We found that lack of MDR-1 gene expression was exclusively associated to favorable cytogenegic patterns in our study. In order to clarify the relationship between the role of MDR-1 gene and clinical outcome or other prognostic features, including cytogenetic pattern, further larger studies would be necessary.

Keywords: Multidrug resistance (MDR-1) gene, Acute myeloid leukemia, CD marker, Cytogenetic pattern,