Konference: 2015 57th ASH Annual Meeting - účast ČR
Kategorie: Maligní lymfomy a leukémie
Téma: 618. Acute Lymphoblastic Leukemia: Biology, Cytogenetics and Molecular Markers in Diagnosis and Prognosis: Poster
Číslo abstraktu: 1410
Autoři: MD Sabina Chiaretti, PhD; Sara Grammatico; Dr. Alfonso Piciocchi; Monica Messina; Anna Lucia Fedullo; Valentina Gianfelici; Grazia Fazio, Ph.D.; Nadia Peragine; Maria Paola Martelli; Paola Fazi; Dr. Marco Vignetti; MD Antonella Vitale; MUDr. Mgr. Cyril Šálek, Ph.D.; Giovanni (Gianni) Cazzaniga, PhD; Anna Guarini, Ph.D.; Robert (Robin) Foa (Foà)
Aims: To generate a simple and reliable tool, based on a Q-RT-PCR approach, aimed at the rapid identification ofBCR/ABL1-like cases, and to build a statistical predictive model. Finally, to correlate the results obtained with the clinico-biologic features and outcome.
Methods and patients: Through a meta-analysis of previously published GEP data focused on BCR/ABL1-like cases, and on our in house results, 9 commonly overexpressed genes were selected and evaluated by Q-RT-PCR; CRLF2was also included, because of its association with this signature (total=10 genes). Q-RT-PCR was performed using the ABI PRISM 7300 Sequence Detection System and FastStart Universal SYBR Green Master (Rox). Overall, 149 B-lineage ALL cases, negative for known major rearrangements, i.e. BCR/ABL1, ETV6/RUNX1, E2A/PBX1 and ALL1 (B-NEG ALL), were tested. Median age was 28.8 years (range 1-78), 59 were females and 90 males. To generate a predictive model for BCR/ABL1-like identification, one round of cross-validation was performed; the full dataset was divided into two panels (discovery and screening). The discovery panel included 52 cases previously evaluated for GEP analysis and comprised 26 BCR/ABL1-like and 26 B-NEG ALL samples, while the screening panel (n=97) was based on 81 cases including 16 B-NEG ALL samples harboring JAK2, IL7R or CRLF2 mutations, tested as internal control, given their association with a BCR/ABL1-like signature.
Results: The statistical model was built on the discovery panel and was validated, in terms of sensitivity and specificity, on the screening panel. Q-RT-PCR values of the 10 genes were grouped in the discovery panel according to principal component analysis to reduce multicollinearity and a logistic regression model was used to examine the association among the first three principal components (accounting for more than 80% of the total variance) andBCR/ABL1-like cases. Finally, a score was computed and validated in the screening panel. The model had a sensitivity and specificity of 93.8% and 93.8%, respectively, with a positive predictive value of 75%. Within the screening panel, 10/81 (12.3%) and 6/16 JAK2, IL7R or CRLF2 mutated cases (37.5%) were predicted as BCR/ABL1-like (total=16.5%). GEP was performed on 14/16 BCR/ABL1-like samples and confirmed the similarity withBCR/ABL1+ ALL cases by unsupervised and supervised analysis. Molecular screening, comprising the screening ofJAK1/2, CRLF2, IL7R (JAK/STAT pathway) mutations and IKZF1 deletions, confirmed a significant enrichment of the JAK/STAT pathway (48% vs 15%, p=0.001) and of IKZF1 deletions (82 vs 46%, p=0.006) in BCR-ABL1-like cases as opposed to the other B-NEG ALL cases. Finally, BCR-ABL1-like patients showed a significantly higher white blood cells (WBC) count (46x109/l vs 12.8x109/l, p=0.003) and poorer prognosis compared to the other B-NEG ALL patients, in terms of complete remission achievement (70.3 vs 87%, p=0.07), overall survival (41.1% vs 59.1%, p=0.06) and disease-free survival (DFS) (31.1 % vs 46%, p=0.008).
Conclusions: We describe a Q-RT-PCR approach and a statistical model capable of rapidly identifying BCR-ABL1-like cases. We confirm a significant association with JAK/STAT mutations, IKZF1 deletions and poorer outcome. The prompt recognition of BCR-ABL1-like ALL at presentation can: i) identify cases in which additional lesion/s involving a TK - that might sustain the BCR/ABL1-like signature - should be further investigated; ii) drive therapeutic decisions, since these patients might benefit by the addition of targeted therapies, particularly TK inhibitors.
Datum přednesení příspěvku: 5. 12. 2015