Objective To clarify the polo-like kinasel (PLKI) expression in human gastric cancer tissue and its clinicopathological significance in gastric carcinoma. Methods PLKl expression in 60 cancer tissues and their corresponding noncancerous tissues from gastric cancer patients was measured by both real-time quantitative RT-PCR and western blot assay. Immunohistochemistry was used to detect PLKI protein expression in eighty-nine paraffin-embedded samples. Results The PLKI mRNA and protein expression level in the 60 fresh cancer tissues was significantly higher than that in noncancerous tissues (P <0. 0001, P =0. 031 respectively). In paraffin-embedded samples, apart from its increased expression level, PLKI was found to be in both cytoplasm and nucleus, double-site location only occurred in poor-differentiated cancer, PLKI expression intensity was associated with tumor differentiation (P = 0. 03) , invasion (P = 0. 032) , TNM stage (P=0.019), ki67 expression (P =0.011). The patients with negative PLKl expression had better survival rate than that with positive PLKl expression (P = 0. 0292). Conclusion PLKl may have clinicopathological value in tumor diagnosis, and may become another new bio-marker and therapeutic target for gastric cancer. Objective To clarify the polo-like kinasel (PLKI) expression in human gastric cancer tissue and its clinicopathological significance in gastric carcinoma. Methods PLKl expression in 60 cancer tissues and their corresponding noncancerous tissues from gastric cancer patients was measured by both real-time quantitative RT Results of PLHI mRNA and protein expression level in the 60 fresh cancer tissues was significantly higher than that in noncancerous tissues (P < 0 0001, P =0. 031 respectively). In paraffin-embedded samples, apart from its increased expression level, PLKI was found to be in both cytoplasm and nucleus, double-site location only occurred in poor-differentiated cancer, PLKI expression intensity Was associated with tumor differentiation (P = 0. 03), invasion (P = 0. 032), TNM stage (P=0.019), ki67 expression (P =0.011). The patients with ne Gative PLKl expression had better survival rate than that with positive PLKl expression (P = 0. 0292). Conclusion PLK1 may have clinicopathological value in tumor diagnosis, and may become another new bio-marker and therapeutic target for gastric cancer.