title: Validation by RQ-PCR and flow cytometry of alpha-defensin1-3 (DEFA1-3) overexpression in relapsed and refractory acute lymphoblastic leukemia.
abstract: In spite of high cure rates and improved overall survival, 25% of pediatric patients with acute lymphoblastic leukemia (ALL) relapse after obtaining complete remission. Additionally a small proportion of patients are refractory and do not attain remission. Microarray expression analysis of matched diagnosis-relapse B-lineage ALL sample pairs identified DEFA1-3 as a potential marker of relapse. Here, validation of DEFA1-3 as a marker for therapy resistance is explored. DEFA1-3 expression was analysed by RQ-PCR in patient paired samples at diagnosis and relapse of 6 early-relapse (within 18 months) and 8 late-relapse (beyond 18 months) B-lineage ALL. Diagnostic samples of 19 patients with ALL who are in continuous complete remission (median time from diagnosis 47 month) and diagnostic samples of 5 refractory patients who had not achieved remission at day 35 of therapy were also analyzed. In addition, overexpression of alpha-defensin1-3 proteins in blast cells at relapse was analysed by flow cytometry. DEFA1-3 was overexpressed at relapse as compared to diagnosis in 12 of 14 samples. At diagnosis, the expression of DEFA1-3 was significantly higher in samples from refractory patients as compared to those of patients who are in CR and to those of patients who experienced late relapse. At diagnosis, patients who relapsed early after diagnosis could not be distinguished from refractory patients based on DEFA1-3 expression levels. Results suggest that high levels of DEFA1-3 mRNA and alpha-defensin1-3 protein expression are correlated with disease progression and failure of adequate response to conventional chemotherapy.
authors.affiliation: Department of Pediatrics, University of Padova, via Giustiniani 3, I-35128 Padova, Italy. truustekronnie@unipd.it.
authors.forename: Geertruy
authors.initials: G
authors.lastname: Te Kronnie
authors.forename: Silvio
authors.initials: S
authors.lastname: Bicciato
authors.forename: Lisa
authors.initials: L
authors.lastname: Franceschini
authors.forename: Benedetta
authors.initials: B
authors.lastname: Accordi
authors.forename: Marta Campo
authors.initials: MC
authors.lastname: Dellíorto
authors.forename: Andrea
authors.initials: A
authors.lastname: Rinaldi
authors.forename: Andrea
authors.initials: A
authors.lastname: Pession
authors.forename: Elena
authors.initials: E
authors.lastname: Barisone
authors.forename: Valentino
authors.initials: V
authors.lastname: Conter
authors.forename: Franco
authors.initials: F
authors.lastname: Locatelli
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Basso
mesh_terms: D000293:Adolescent; D000970:Antineoplastic Agents / Q000627:therapeutic use; D014408:Biomarkers, Tumor / Q000032:analysis*; D002648:Child; D002675:Child, Preschool; D026281:DEFICIENS Protein / Q000096:biosynthesis*; D019008:Drug Resistance, Neoplasm; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D017403:In Situ Hybridization; D007223:Infant; D008297:Male; D009364:Neoplasm Recurrence, Local / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology*; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015854:Up-Regulation
chemical_list: D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor; D026281:DEFICIENS Protein; D012333:RNA, Messenger