NOTCH1 and B-cell chronic lymphocytic leukemia: However, cytogenetic analyses have indicated the presence of frequent complex chromosomal alteration in CLL [28] and recent advances in high throughput sequencing have revealed an even more complex genetic landscape, with novel mutations of prognostic power being identified such as mutations within the genes encoding Notch1, MyD88, Birc3, and Xpo1 [29],[30].