On page 2901 in the 10 March 2011 issue, there is an error in the second sentence of the “Introduction”; the statistics for T-ALL occurrence in adults and children with ALL were inverted. The sentence read, “T-ALL accounts for approximately 10% to 15% of adult and 25% of childhood ALL cases.” The sentence should have read: “T-ALL accounts for approximately 10% to 15% of childhood and 25% of adult ALL cases.”