A flow cytometric analysis on the peripheral blood (PB) documented a B-cell clone expressing CD5, CD23, CD20 (dim), CD38 and CD200, consistent with CLL; cytogenetics and molecular studies documented chromosome 11q deletion, with an unmutated IGHV status, and wild-type NOTCH1 and TP53 genes. This evidence concerns the gene TP53 and B-cell chronic lymphocytic leukemia.