LCK and B-cell chronic lymphocytic leukemia: The data provided by Märklin et al. support our findings that Lck is overexpressed in human CLL compared to normal B cells, however, whereas these same data show that low levels of Lck are associated with CLL cells from patients with aggressive disease, we find no such correlation of Lck expression with markers of poor prognosis in the cells from the cohorts of patient samples we analyzed.