Abstract: The Affiliated Union Hospital, Fujian Medical University, Fuzhou 350001 In this study, the levels of nm23 gene product/NDPKexpression were detected by anti-NDPK polyclonal antibody. pure bred mice were divided into three groups:(1)Control group, (2)AFB₁-infected group, and (3)AFB₁ plus tobacco smoking group. Crystalline AFB₁ was dissolved in DMSO and fed the experimental mice. The intensities of nm23/NDPK expression in liver slides were measured by Medical Image Process System. The expression intensities were shown as follow:AFB₁ infected group AFB₁ plus tobacco smoking groupControl group. There were significant differences among thethree groups. We proposed that the increased expression of nm23/NDPK was related toproliferative activity of AFB₁-induced precancerous cell in mice liver, and that cigarette smoking might be protected against AFB₁-induced primary cancer of the liver in mice.