BACKGROUND: In recent years, recombined human growth hormone (rhGH) has been increasingly used in patients to help them recover from operation. But GH, as a mitogen, can promote cell renewal and increase malignant transformation. In the current study, we assessed the proliferation of a bile duct cancer cell line (QBC939) in vitro with GH and explored the possible relationship with the axis of GH-IGFs (insulin-like growth factors). METHODS: QBC939 cells in the exponential growth stage were harvested and divided into an experimental group (GH group) and a control group (NS group). The GH group was divided into four sub-groups according to the dose of GH and culture time (50 μg/L for 2 hours, 50 μg/L for 24 hours, 100 μg/L for 2 hours, 100 μg/L for 24 hours). The NS group was divided into two sub-groups (NS for 2 hours and NS for 24 hours). After 2 or 24 hours IGF-1 and IGF-2 were detected using the enzyme-linked immunosorbent assay. The QBC939 cells cultured for 24 hours with two GH concentrations were made into single cell suspensions and samples underwent subsequent cell cycle evaluation. Messenger RNA of IGF-1 and IGF-2 receptor (IGF-1RmRNA and IGF-2RmRNA) were tested with the method of in situ hybridization. RESULTS: There was no statistically significant difference between the GH and NS groups after 2 hours of culture (P>0.05). But after 24 hours of culture, GH stimulated cell growth in vitro and also elevated the percentage in S phase and the proliferation index (P<0.05). IGF-1RmRNA and IGF-2RmRNA were expressed in QBC939 in contrast to theblank group. The expression of IGF-1RmRNA increased with the dose of GH, but IGF-2RmRNA did not. CONCLUSION: GH can stimulate QBC939 cell growth and proliferation in vitro and the mechanism is most likely by the GH-IGF-1-IGF-1R axis. BACKGROUND: In recent years, recombined human growth hormone (rhGH) has been increasingly used in patients to help them recover from operation. But GH, as a mitogen, can promote cell renewal and increase malignant transformation. In the current study, we evaluated the proliferation of a bile duct cancer cell line (QBC939) in vitro with GH and explored the possible relationship with the axis of GH-IGFs (insulin-like growth factors). METHODS: QBC939 cells in the exponential growth stage were harvested and divided into an (GH group) and a control group (NS group). The GH group was divided into four sub-groups according to the dose of GH and culture time (50 μg / L for 2 hours, 50 μg / L for 24 hours , 100 μg / L for 2 hours, 100 μg / L for 24 hours). The NS group was divided into two sub-groups (NS for 2 hours and NS for 24 hours). After 2 or 24 hours IGF-1 and IGF -2 were detected using the enzyme-linked immunosorbent assay. The QBC939 cells cultured for 24 hours with two GH concentrations were made into single cell suspensions and samples underwent subsequent cell cycle evaluation. Messenger RNA of IGF-1 and IGF-2 receptor (with IGF-1R mRNA and IGF-2R mRNA) were tested with the method of in situ hybridization. statistically significant difference between the GH and NS groups after 2 hours of culture (P> 0.05). But after 24 hours of culture, GH stimulated cell growth in vitro and also the percentage in S phase and the proliferation index (P <0.05) . IGF-1RmRNA and IGF-2RmRNA were expressed in QBC939 in contrast to theblank group The expression of IGF-1RmRNA increased with the dose of GH, but IGF-2RmRNA did not CONCLUSION:.. GH can stimulate QBC939 cell growth and proliferation in vitro and the mechanism is most likely by the GH-IGF-1-IGF-1 R axis.