PMS2 and precursor B-cell acute lymphoblastic leukemia: Ultra-deep sequencing (>3000x) in all the newly diagnosed B-ALL cases using a custom NGS panel for the KRAS, NRAS, TP53, UHRF1 and CREBBP genes, followed by prospective testing of sequential samples (3-monthly) with a panel with additional NT5C2, PMS2, KMT2D, ETV6 and PAX5 genes will likely help to identify a significant proportion of cases with impending relapse, although this strategy might require dynamic modification based on prospective data emerging from the relapse biology in our setting.