NOTCH1 and B-cell chronic lymphocytic leukemia: Despite the still-widening list of prognostically significant genes, the only biomarker that influences the treatment strategy remains the presence of TP53 defects [98], and to date, there has not been enough evidence to support the use of NOTCH1, SF3B1, BIRC3 or ATM mutations, or CLL subclonal composition in making clinical decisions.