In a study on previously untreated high-risk CLL (defined by the presence of U-IGHV gene and/or chromosome 11q22 deletion and/or chromosome 17p13 deletion and/or TP53 mutations) the presence of CK in 21/101 (20.8%) cases has been associated with unfavorable FISH (i.e. 11q- or 17p-) (P<0.001) and TP53 disruption (P=0.012). The gene discussed is TP53; the disease is B-cell chronic lymphocytic leukemia.