['Patients affected by chronic lymphocytic leukemia (CLL) have an increased risk of developing a second cancer. There is not a definitive explanation for this phenomenon, although some hypotheses have been postulated. The aim of the present work was to assess the presence of second cancer in untreated patients with CLL who were cytogenetically characterized, and secondly to investigate if there is a correlation between the genetics of CLL and the emergence of second cancer.', 'We performed conventional cytogenetics and Fluorescent in situ hybridization analyses in a series of 106 patients.', 'We observed that nearly 8% of cases developed second cancer, mostly epithelial tumors. The majority of them presented two common features, del(13)(q14.3) and the presence of at least two genetic alterations.'] Does genetics of lymphocytes influence the emergence of second cancer in chronic lymphocytic leukemia?