Long-Term Use of Acetaminophen, Aspirin, and Other Nonsteroidal Anti-Inflammatory Drugs and Risk of Hematologic Malignancies: Results From the Prospective Vitamins and Lifestyle (VITAL) Study.
Walter RB, Milano F, Brasky TM, White E.
J Clin Oncol. 2011 May 9.

CONCLUSION High use of acetaminophen was associated with an almost two-fold increased risk of incident hematologic malignancies other than CLL/SLL. Neither aspirin nor nonaspirin NSAIDs are likely useful for prevention of hematologic malignancies.

see also:
Reuters May 9, 2011