Detection of bone marrow micrometastasis and microcirculating disease in rhabdomyosarcoma by a real-time RT-PCR assay.
OBJECTIVE
To assess if molecular detection of minimal disseminated disease by real-time reverse transcription and polymerase chain reaction (RT-PCR) could contribute to a better treatment stratification in patients with rhabdomyosarcoma (RMS).


METHODS
Relative quantification of the tumor-mRNA present in serial samples of bone marrow (BM) and peripheral blood (PB) from 16 patients with RMS (7 alveolar and 9 embryonal) was performed by a real-time RT-PCR assay. Expression of MyoD1 and acetylcholine receptor (AChR) was analyzed in all samples, along with PAX3/7-FKHR in samples from alveolar tumors.


RESULTS
A good correlation was found between the expression of PAX3/7-FKHR and AChR, while MyoD1 was more sensitive but less specific. In this study, patients with positive PB at the end of treatment showed a poorer prognosis than patients with negative PB. Moreover, in this patient cohort, metastatic relapses were preceded by the detection of microcirculating disease in all cases.


CONCLUSIONS
The detection of minimal circulating and micrometastatic disease by real-time RT-PCR, based on the expression of multiple genes, yields highly reproducible results. Patients with positive PB after treatment show poorer survival than patients without microcirculating disease.
Gallego
Soledad
S
Pediatric Oncology Unit, Hospital Universitari Vall d'Hebron, Barcelona, Spain. sgallego@vhebron.net
Llort
Anna
A
Roma
Josep
J
Sabado
Constantino
C
Gros
Luis
L
de Toledo
Josep Sanchez
JS
D000293:Adolescent; D014408:Biomarkers, Tumor / Q000235:genetics; D019046:Bone Marrow Neoplasms / Q000175:diagnosis* / Q000235:genetics / Q000556:secondary*; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D020869:Gene Expression Profiling; D006801:Humans; D007223:Infant; D008297:Male; D017570:MyoD Protein / Q000235:genetics; D009367:Neoplasm Staging; D018365:Neoplasm, Residual; D009360:Neoplastic Cells, Circulating / Q000378:metabolism; D015514:Oncogene Proteins, Fusion / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D011978:Receptors, Nicotinic / Q000235:genetics; D012008:Recurrence; D012189:Retrospective Studies; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods*; D018232:Rhabdomyosarcoma, Alveolar / Q000097:blood / Q000175:diagnosis* / Q000235:genetics; D018233:Rhabdomyosarcoma, Embryonal / Q000097:blood / Q000175:diagnosis* / Q000235:genetics; D012680:Sensitivity and Specificity; D015996:Survival Rate
D014408:Biomarkers, Tumor; D017570:MyoD Protein; C057363:MyoD1 myogenic differentiation protein; D015514:Oncogene Proteins, Fusion; D012333:RNA, Messenger; D011978:Receptors, Nicotinic