NPM1 gene mutation is a well-known prognostic marker in AML, probably related to its cytoplasmic localization. NPM1 gene mutation detection could be done by either molecular genetics or its protein product by immunohistochemical staining of bone marrow (BM) biopsy.
This study aimed to compare the detection rate of the immuno-staining technique for mutated nucleophosmin-1 gene when applied on the standard BM biopsy versus BM aspirate or BM clot biopsy in adult de novo patients of acute myeloid leukemia.
Forty adult patients (18-60 years) with newly diagnosed AML were enrolled into this study. Detection of nucleophosmin localization either nucleolar or cytoplasmic was performed using monoclonal mouse anti-human nucleophosmin (clone 376) by conventional immunohistochemical technique on BM biopsy, BM aspirate & BM clot biopsy.
The study included 40 AML patients, 23 males, 17 females. The complete remission (CR) rate was 70%. Median overall survival (OS) was 2.5 month (0.1-40 months). Median disease free survival was 6 month (0.2-39). NPM1 was detected in 11/40 patients by conventional immunohistochemical technique on BM biopsy, 11/39 patients by BMA technique, and 9/29 by BM clot technique. The BMA technique had Sensitivity of 100%, Specificity of 78.6%, positive predictive value of 64.7%, negative predictive value of 100%, and diagnostic accuracy of 84.6%. The BM clot technique had sensitivity of 77.8%, specificity of 90.0%, and positive predictive value of 77.8%, negative predictive of 90.0%, and diagnostic accuracy 86.2%.
The BMA technique had good sensitivity and so could be used as a cheap screening method even in patients with profound thrombocytopenia. BM clot technique had good specificity. Both BMA and BM clot techniques could be a reasonable cheap option if combined together in cases in which BM biopsy could not be done.