Using quantification of the PML-RARalpha transcript to stratify the risk of relapse in patients with acute promyelocytic leukemia.
OBJECTIVE
The detection of PML-RARalpha by real-time polymerase chain reaction (RQ-PCR) is becoming an important tool for monitoring minimal residual disease (MRD) in patients with acute promyelocytic leukemia (APL). However, its clinical value remains to be determined. Our aim was to analyze any associations between the risk of relapse and RQ-PCR results in different phases of treatment, comparing these data with those yielded by conventional qualitative reverse transcriptase-PCR.


METHODS
Follow-up samples from 145 APL patients treated with the PETHEMA protocols were evaluated by the RQ-PCR protocol (Europe Against Cancer program) and by the RT-PCR method (BIOMED-1 Concerted Action). Hematologic and molecular relapses and relapse-free survival were recorded. We then looked for associations between relapse risk and RQ-PCR results.


RESULTS
After induction therapy, no association was found between positive RQ-PCR results and relapse. The PCR result here did not imply any change in the scheduled therapy. After the third consolidation course, two out of three cases with positive RQ-PCR relapsed in contrast to 16 out of 119 (13%) patients with negative RQ-PCR. During maintenance therapy and out-of treatment, all patients with >10 PML-RARalpha normalized copy number (NCN) (n=19) relapsed while all patients with <1 NCN at the end of the study remained in hematologic remission (p<0.0001). In the intermediate group (NCN 1-10) (n=18), the relapse-free survival at 5 years was 60%. Hematologic relapses were predicted if a positive RQ-PCR result had been obtained in a follow-up sample within the previous 4 months.


CONCLUSIONS
Based on the information provided by RQ-PCR in samples obtained after the end of consolidation and subsequently, a relapse risk stratification could be established for APL patients. This stratification divides patients into three groups: those at high risk of relapse, those with an intermediate risk and those with a low risk of relapse.
Santamaría
Carlos
C
Departament of Hematology, Hospital Universitario de Salamanca, Salamanca, Spain.
Chillón
Maria Carmen
MC
Fernández
Carina
C
Martín-Jiménez
Patricia
P
Balanzategui
Ana
A
García Sanz
Ramón
R
San Miguel
Jesús F
JF
González
Marcos-Gonzalez
MG
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000008:administration & dosage / Q000627:therapeutic use*; D014408:Biomarkers, Tumor / Q000097:blood* / Q000235:genetics; D002648:Child; D002986:Clinical Trials as Topic / Q000706:statistics & numerical data; D003199:Computer Systems; D018076:DNA, Complementary / Q000235:genetics; D018572:Disease-Free Survival; D016903:Drug Monitoring; D005260:Female; D005500:Follow-Up Studies; D018628:Gene Dosage; D006801:Humans; D015255:Idarubicin / Q000008:administration & dosage; D053208:Kaplan-Meier Estimate; D015473:Leukemia, Promyelocytic, Acute / Q000097:blood / Q000188:drug therapy* / Q000235:genetics; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D015337:Multicenter Studies as Topic / Q000706:statistics & numerical data; D018365:Neoplasm, Residual; D015514:Oncogene Proteins, Fusion / Q000097:blood* / Q000235:genetics; D016133:Polymerase Chain Reaction / Q000379:methods*; D011237:Predictive Value of Tests; D012333:RNA, Messenger / Q000097:blood; D012334:RNA, Neoplasm / Q000097:blood; D012008:Recurrence; D012074:Remission Induction; D018570:Risk Assessment; D016879:Salvage Therapy; D012680:Sensitivity and Specificity; D016019:Survival Analysis; D014212:Tretinoin / Q000008:administration & dosage
D014408:Biomarkers, Tumor; D018076:DNA, Complementary; D015514:Oncogene Proteins, Fusion; D012333:RNA, Messenger; D012334:RNA, Neoplasm; C093476:promyelocytic leukemia-retinoic acid receptor alpha fusion oncoprotein; D014212:Tretinoin; D015255:Idarubicin