The present study examined cytokine expression in leukemia in relation to Toll-like receptors (TLR). 19 leukemia and lymphoma cases were analyzed by flow cytometry for selected cytokines and TLR, including IL-2, IL-3, IL-4, IL-6, IL-10, IL-12, TNF-α, IFN-γ, TLR3, TLR4, TLR8, and TLR9. All 18 (100%) cases expressed IL-2, IL-4, and TNF-α. IL-2 expression was dim in 14 (77.8%) of 18 cases with moderate and bright expression in the other 3 (16.7%) and 1 (5.6%) cases, respectively. All IL-4 expression was dim. Conversely, TNF-α expression was mainly heterogeneously bright or moderate in 14 (77.8%) cases with 4 (22.2%) cases of dim expression. 17 of 18 (94.4%) cases were dually positive for IL-3 and IFN-γ with the remaining case negative for both. IL-3 and IFN-γ, were moderately expressed in 9 (52.9%) and 12 (70.6%) of 17 cases, respectively, with dim expression for both eytokines in the remaining cases. Of the 14 cases evaluated for IL-6, IL-10, and IL-12, only 2 (14.3%) expressed IL-6 and IL-12, whereas 3 (21.4%) were positive for IL-10, which was coexpressed in each case positive for IL-6. All 14 cases (100%) analyzed for TLR homogeneously expressed TLR9 moderately while none (0%) of the cases was positive for TLR4 or TLR8. Five (35.7%) cases expressed TLR3 dimly. These cytokine levels may be linked to the MyD88 and TRIF adaptors involved in TLR signal transduction, warranting further study in leukemic cytokine and TLR profiles. [ABSTRACT FROM AUTHOR]