ORIGINAL ARTICLE |
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Year : 2016 | Volume
: 143
| Issue : 6 | Page : 763-768 |
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Nucleophosmin mutation analysis in acute myeloid leukaemia: Immunohistochemistry as a surrogate for molecular techniques
Anita Chopra1, Sushant Soni1, Haraprasad Pati2, Dev Kumar1, Rahul Diwedi1, Deepak Verma1, Garima Vishwakama1, Sameer Bakhshi3, Suman Kumar4, Ajay Gogia3, Rajive Kumar1
1 Department of Laboratory Oncology, Institute Rotary Cancer Hospital, All India Institute of Medical Sciences, New Delhi, India 2 Department of Haematology, All India Institute of Medical Sciences, New Delhi, India 3 Department of Medical Oncology, Institute Rotary Cancer Hospital, All India Institute of Medical Sciences, New Delhi, India 4 Command Hospital (Eastern Command), Kolkata, India
Correspondence Address:
Rajive Kumar DII/44, AIIMS campus, Ansari Nagar, New Delhi 110 029 India
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/0971-5916.192027
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Background & objectives: Mutation of nucleophosmin (NPM1) gene in the absence of FLT3-ITD (FMS related tyrosine kinase 3 - internal tandem duplications) mutation carries a good prognosis in cytogenetically normal acute myeloid leukaemia (AML). NPM1, a multifunctional nucleolar phosphoprotein that shuttles between nucleus and cytoplasm, gets trapped in the cytoplasm when mutated. Immunohistochemical (IHC) demonstration of its aberrant cytoplasmic location (NPMc+) has been suggested as a simple substitute for the standard screening molecular method. This study was aimed to assess the diagnostic utility of IHC on formalin fixed bone marrow biopsies in comparison with the reference molecular method (allele specific oligonucleotide - polymerase chain reaction; ASO-PCR) to predict NPM1 mutation status in AML patients.
Methods: NPM protein IHC was performed using mouse anti-NPM monoclonal antibody on 35 paraffin-embedded bone marrow biopsies of patients with primary AML of any French-American-British (FAB) subtype. Results of IHC were compared with those of ASO-PCR.
Results: Of the 35 AML patients, 21 (60%) were positive for NPM1 exon 12 gene mutation by ASO-PCR, 19 (90.47%) of these 21 were NPMc+. Thirteen of the 35 patients were negative by both the methods. One NPMc+ patient was not detected by ASO-PCR. IHC had a sensitivity and specificity of 90 and
93 per cent, respectively, compared to the molecular screening gold standard.
Interpretation & conclusions: Mutation of NPM1 determined by the widely available and inexpensive IHC agrees closely with results of the standard molecular methods. Thus, technically and financially not well endowed laboratories can provide the prognostically and potentially therapeutically important information on NPM1 mutation using IHC. |
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