Epigenetically dysregulated NOTCH-Delta-HES signaling cascade can serve as a subtype classifier for acute lymphoblastic leukemia.

The NOTCH-Delta-HES signaling cascade is regarded as a double-edged sword owing to its dual tumor-suppressor and oncogenic roles, in different cellular environments. In the T-cells, it supports leukemogenesis by promoting differentiation while in B-cells, it controls leukemogenesis by inhibiting early differentiation/inducing growth arrest in the lead to apoptosis. The present study was undertaken to assess if this bi-faceted behavior of NOTCH family can be exploited as a diagnostic biomarker or subtype classifier of acute lymphoblastic leukemia (ALL). In this pursuit, expression of seven NOTCH cascade genes was analyzed in bone marrow (BM) biopsy and blood plasma (BP) of pediatric ALL patients using quantitative PCR (qPCR). Further, promoter DNA methylation status of the differentially expressed genes (DEGs) was assessed by methylation-specific qMSP and validated through bisulphite amplicon sequencing. Whereas hypermethylation of JAG1, DLL1, and HES-2, HES-4, and HES-5 was observed in all patients, NOTCH3 was found hypermethylated specifically in Pre-B ALL cases while DLL4 in Pre-T ALL cases. Aberrant DNA methylation strongly correlated with downregulated gene expression, which restored at complete remission stage as observed in "follow-up/post-treatment" subjects. The subtype-specific ROC curve analysis and Kaplan-Meier survival analysis predicted a clinically applicable diagnostic and prognostic potential of the panel. Moreover, the logistic regression model (Pre-B vs Pre-T ALL) was found to be the best-fitted model (McFadden's R2 = 0.28, F1 measure = 0.99). Whether analyzed in BM-aspirates or blood plasma, the NOTCH epigenetic signatures displayed comparable results (p < 0.001), advocating the potential of NOTCH-Delta-HES cascade, as a subtype classifier, in minimally invasive diagnosis of ALL.

A panel of epigenetically dysregulated Wnt signaling pathway genes for non-invasive diagnosis of pediatric acute lymphoblastic leukemia.

BACKGROUND: Genetic and epigenetic dysregulation of Wnt signaling pathway is widely linked up with abnormal proliferation and/or epithelial-to-mesenchymal transition, in different cancer cell types. OBJECTIVE: In the present research, we have tested whether promoter DNA methylation of a set of Wnt/non-Wnt genes such as [cadherin-2 (CDH2)], "present in circulation", could serve as "bone-marrow biopsy surrogate" and help in diagnosing the status, sub-type or treatment outcome in pediatric acute lymphoblastic leukemia (ALL) patients. METHODS: Promoter DNA methylation was quantified in the bisulfite modified blood from the pediatric ALL patients (n= 86) in comparison with age-matched cancer-free subjects (n= 28), using real-time methylation specific PCR followed by rigorous statistical validations. RESULTS: The observed methylation index, sensitivity and specificity of selected molecular markers (viz., SALL1, WNT5α, LRP1b, CDH2) in patients' liquid-biopsies was clinically significant showing high positive correlation in the pre-B ALL cases (p-value < 0.001). A substantial drop in promoter methylation signal of the follow-up/post-treatment patients was also noted (p-value < 0.001), which suggested an impending role of minimally invasive liquid-biopsy approach in the diagnosis and/or therapeutic monitoring of pediatric leukemia. CONCLUSIONS: Whilst the reported metadata provides useful insight into the plausible involvement of epigenetic glitches in leukemogensis, our findings strengthen the remarkable functional consequences of dysregulated Wnt signaling genes in the hematological malignancies besides offering a novel panel of epigenetic marks.