AffiCHECK® NPM1 Control Panel
The purpose of the AffiCHECK® NPM1 Control Panel is to serve as a benchmark material for overseeing the precision of nucleic acid testing methods within laboratory settings. These procedures aim to quantitatively identify the NPM1 Type A mutant mRNA transcript and ABL1 endogenous control mRNA transcript through analysis using the Xpert® NPM1 Mutation assay on Cepheid GeneXpert® Instrument Systems.
The nucleophosmin-1 gene (NPM1) encodes a remarkably versatile protein that plays key roles in nucleocytoplasmic protein transportation, protein chaperoning, ribosome formation, cell cycle progression, and apoptosis regulation. Mutations involving tetranucleotide insertions in exon 12 of NPM1 are frequently observed in hematopoietic cancers, constituting approximately one-third of adult acute myeloid leukemia cases. Among these, the 'Type A' NPM1 mutation (TCTG insertion in exon 12) accounts for almost 80% of all NPM1 gene modifications. These insertions disrupt the reading frame in the NPM1 gene, resulting in the loss of a C-terminal nucleolar localization signal and the creation of a new nuclear export signal, leading to the relocation of NPM1 protein from the nucleus and nucleolus to the cytoplasm. This relocation is associated with the destabilization of vital tumor-suppressors p53 and ARF, both regulated by NPM1. Mutations in NPM1 are now recognized as a distinct category of leukemias by the World Health Organization (WHO). Quantitative monitoring of NPM1 transcripts, particularly the prevalent Type A mutant RNA, in patient blood is an invaluable method for assessing treatment responses.
The AffiCHECK® NPM1 Control Panel includes 5 distinct components, each containing a varying concentration of NPM1 Type A mutant RNA transcript, combined with consistent levels of ABL1 and wildtype NPM1 transcripts. These components yield 5 different levels of Type A Mutant RNA to ABL1 RNA ratios: L0%, L1%, L2%, L3%, and L4%. The L0% level exclusively features wildtype NPM1 and wildtype ABL1 transcripts.
Validation and Value Assignment
AffiGEN produced and evaluated 3 batches of AffiCHECK® NPM1 Control Panel, assessing them across 5 Xpert NPM1 Mutation cartridge lots, encompassing multiple testing days and operators. Grubb’s outlier test was utilized to eliminate statistical anomalies, allowing the remaining data to allocate percentage values to each level. Figure 1 presents a comparison between the reported values of each of the 3 lots of AFG-CHK-1004 and the assigned values, showcasing a consistent linear relationship across the reported value range.
The AffiCHECK® NPM1 Control Panel comprises 10 individual bottles, each containing 4 mL of synthetic RNA transcripts, housed within a stabilizing matrix alongside non-infectious buffers and preservatives. Within these bottles, there are 2 samples for every percentage of the NPM1 mutation. Specifically, the L0% level includes wildtype NPM1 and ABL1 RNA transcripts. Meanwhile, the L1%, L2%, L3%, and L4% levels encompass varying proportions of NPM1 Type A mutant RNA transcripts to ABL1 RNA transcripts set against a background of NPM1 wildtype RNA.
AffiCHECK® AffiCHECK® NPM1 Control Panel must be sored at -20°C. Unopened package remains stable until the indicated expiration date.