Recently, the alternative therapies on cancer care became more popular and acceptable in the world including complementary medicine or supportive therapy such as MT or massage. However, many adverse effects concerning the possibility to promote metastasis have been reported. From clinical findings, many OS patients seek for manipulative therapy to 
release the uncomfortable symptoms such as swelling or pain before diagnosis without alerting the possibility of OS exist. In our clinical results from 200 OS patients, the metastasis rate were higher and the survival rate were lower in OS patients who had received MT treatment before diagnosis compared with MT patients, Ganoderic-acid-F respectively. Such mechanical massage on cancer patients might lead to tumor cell lesion spreading to lymph nodes near the tumor sites that were 9-methoxycamptothecine reported on breast cancer patients and also proved in OS patients from our clinical and in vivo study. Though MT is a useful supportive therapy for cancer patients after surgery, the treatment should be paid more a ention before diagnosis. Mice osteosarcoma model was established in this study by intratibial injection of human OS cells followed by MT treatment to prove the effects of MT on OS metastasis according to clinical findings. The MT treatment was modified from Bertsch et al and Liu and Huang who claimed that massage promoted cell proliferation or induce gene delivery. Though it was difficult to assay the pressure on mice skin when conducting MT treatment, we standardize the MT protocol by pu ing the force on xenografted tumor as a touch press pushing back and forth for three times per treatment and two treatments per week for simulating the clinical manipulation protocol. Under MT treatments, the cancer cells migrated not only into bilateral lymph nodes but also in lung tissue that detected by micro-PET/CT and X-ray images on lymph nodes while GFP-labeled cells were noted even in lung. Such GFP-labeled tumor cells have been reported as a strong tool for monitoring the cell metastasis in animals. These results provide direct evidence of MT-induced OS metastasis in vivo. Our results showed obvious cell migration after MT treatment that validated the experiment model. Though tibial injection may cause the leaking of tumor cells, we did not detect any tumor cells in lung of left lymph node in MT group that eliminated the possibility of artificial leaking. With regard to MT-induced metastasis, there are several mechanisms proposed to explain such phenomenon. 1) mechanical force-induced lymphatic spreading. It was reported that mechanical transport of epithelial cell to axillary lymph node caused by prior surgery manipulation may be through the mechanical force induced cell lesion. 2) mechanical forceinduced MMPs expression. Previous studies showed that MMP families were known as a extracellular matrix factor that participates in cell migration that related to tumor metastasis. 3) both mechanisms involved. In OS patients, it was reported that the high expression level of MMPs indicates poor prognosis and higher metastasis risks. The serum level of MMP2 and MMP9 were both up-regulated under MT treatment under the mechanical damage indicated the highly migration ability of tumor cells while MMP13 also showed the enhanced trend.