Today, cancer is one of the most important causes of death in the world, and so far, many treatment methods have been used in this field. One of the newest achievements of that science is immunotherapy, which is still conducting many types of research in different cancers and with various antigens. One of the subsets of cancer immunotherapy is its treatment using parasitic antigens. In the present study, the effect of using somatic antigens of protoscoleces of Echinococcus granulosus on K562 cancer cells has been interpreted. In this experimental study, hydatid cysts\\\\\\\\\\\\\\\' protoscolex antigens were extracted, purified, and added to K562 cancer cells at three concentrations of 0.1, 1, and 2 mg/ml and three times 24, 48, and 72 hours. The number of apoptotic cells was compared to the control flask. It was investigated by the MTT method, the antigen concentration of 2 mg/ml was used as a control sample to investigate its effect on the growth of healthy HFF3 cells, and annexin V and PI tests were also performed to differentiate apoptosis from necrosis. Statistical data analysis was done using SPSS software, and P<0.05 was considered significant. In flasks treated with hydatid cyst protoscolex antigen, all three concentrations significantly reduced the growth of cancer cells compared with the control flask, and concentration 2 of crude antigen significantly caused the death of cancer cells. Also, more cancer cells underwent apoptosis by increasing the time of exposure to the antigen. On the other hand, flow cytometry results also showed that the amount of apoptosis has increased compared to the control group. Protoscolex hydatid cyst somatic antigens induce programmed cell death in K562 cancer cells while being safe for healthy cells; Therefore, it is suggested to do more research on the anti-cancer and therapeutic properties of the antigens of this parasite.

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