Additionally, CLL patients that progress or develop Richter’s transformation on ibrutinib recurrently harbor mutations of tumor-suppressor TP53, splicing factor SF3B1, or NFκB pathway regulator CARD11, however, whether these genetic aberrations may directly impact response to ibrutinib during Richter’s transformation remains unclear (80). Here, TP53 is linked to B-cell chronic lymphocytic leukemia.