ABSTRACT
Objective@#To investigate the current status and real performance of the detection of RUNX1-RUNX1T1 fusion transcript levels and WT1 transcript levels in China through interlaboratory comparison.@*Methods@#Peking University People’s Hospital (PKUPH) prepared the samples for comparison. That is, the fresh RUNX1-RUNX1T1 positive (+) bone morrow nucleated cells were serially diluted with RUNX1-RUNX1T1 negative (-) nucleated cells from different patients. Totally 23 sets with 14 different samples per set were prepared. TRIzol reagent was added in each tube and thoroughly mixed with cells for homogenization. Each laboratory simultaneously tested RUNX1-RUNX1T1 and WT1 transcript levels of one set of samples by real-time quantitative PCR method. All transcript levels were reported as the percentage of RUNX1-RUNX1T1 or WT1 transcript copies/ABL copies. Spearman correlation coefficient between the reported transcript levels of each participated laboratory and those of PKUPH was calculated.@*Results@#①RUNX1-RUNX1T1 comparison: 9 samples were (+) and 5 were (-) , the false negative and positive rates of the 20 participated laboratories were 0 (0/180) and 5% (5/100) , respectively. The reported transcript levels of all 9 positive samples were different among laboratories. The median reported transcript levels of 9 positive samples were from 0.060% to 176.7%, which covered 3.5-log. The ratios of each sample’s highest to the lowest reported transcript levels were from 5.5 to 12.3 (one result which obviously deviated from other laboratories’ results was not included) , 85% (17/20) of the laboratories had correlation coefficient ≥0.98. ②WT1 comparison: The median reported transcript levels of all 14 samples were from 0.17% to 67.6%, which covered 2.6-log. The ratios of each sample’s highest to the lowest reported transcript levels were from 5.3-13.7, 62% (13/21) of the laboratories had correlation coefficient ≥0.98. ③ The relative relationship of the reported RUNX1-RUNX1T1 transcript levels between the participants and PKUPH was not always consistent with that of WT1 transcript levels. Both RUNX1-RUNX1T1 and WT1 transcript levels from 2 and 7 laboratories were individually lower than and higher than those of PKUPH, whereas for the rest 11 laboratories, one transcript level was higher than and the other was lower than that of PKUPH.@*Conclusion@#The reported RUNX1-RUNX1T1 and WT1 transcript levels were different among laboratories for the same sample. Most of the participated laboratories reported highly consistent result with that of PKUPH. The relationship between laboratories of the different transcript levels may not be the same.
ABSTRACT
Objective To investigate the impact of sample typeon the detection of c-KIT exon 17 mutation in acute myeloid leukemia (AML) patients. Methods A retrospective study was conducted on 51 bone marrow samples collected from 37 AML patients [17 maleand 20 female, with a median age of 33 (range from 1 to 82)] at diagnosis or after treatment from June 2016 to August 2018. Of the 37 cases of AML, 24 were t(8; 21) AML, 11 were inv(16)/t(16;16) AML and 2 were non-CBF-AML. RNA and DNA were simultaneously extracted from every sample. PCR followed by Sanger sequencing were used to screen c-KIT exon 17 mutation, and the comparisons were made between paired cDNA and DNAsamples. Results (1) Of the 51 paired samples, 14 pairs were simultaneously detected positive for c-KITmutation in both of cDNA and DNA samples, but 17 pairs were detected negative in both, and the remaining 20 pairswere only detected positive for the mutation in cDNA but not in DNA, with an inconsistency rate of 39.2％. The positive rate of detecting c-KITmutation was significantly higher in cDNA than in DNA samples (66.7％vs 27.5％,P=0.000073). (2)Inconsistent mutation results between paired cDNA and DNA samples occurred in t(8;21)AML, inv(16)AML and non-CBF-AML patients with the inconsistency rate of 36.4％(12/33), 27.2％(3/11) and 71.4％ (5/7), respectively. (3)The inconsistency rate was significantly higher in samples collected after treatment compared with those collected at diagnosis (72.7％vs 13.8％, P=0.00003). (4) All 5 serially monitored patients with c-KITmutation had inconsistency in mutation detection between cDNA and DNA samples during follow up. Conclusion cDNA improves the detection of c-KIT exon 17 mutation in AML patients compared with DNA, which is especially common after treatment.