Clinical Trial of Infusion of Activated NK Cells for the Treatment of Sarcomas

Inclusion Criteria: 1. Patients aged between 0 and 30 years diagnosed with malignant sarcoma, who at the end of conventional treatment still have detectable residual disease (based on imaging techniques) or in case of stable disease or minimal disease when there is an absence of clinical benefit from chemotherapy (poor tolerance due to adverse effects related to chemotherapy). 2. Lansky/Karnofsky index \> 60%. 3. Mild-moderate (\<4) organ functional impairment (hepatic, renal, respiratory), according to National Cancer Institute criteria (NCI CTCAE v5.0). 4. Left ventricular ejection fraction \>39%. 5. Adult subjects who voluntarily signed informed consent prior to the first study intervention. 6. Minor subjects whose representative/legal guardian voluntarily signed the informed consent prior to the first intervention of the study. 7. In the case of mature minors (12 - 17 years of age), in addition to the consent signed by the legal guardian, the minor's assent will be obtained. 8. Women of childbearing capacity must have a negative pregnancy test at the time of inclusion and must agree to use highly effective contraceptive methods (diaphragms plus spermicide or male condom plus spermicide, oral contraceptive combined with a second method of contraceptive implant, injectable contraceptive, permanent intrauterine device, sexual abstinence or partner with vasectomy) during their participation in the study and within 30 days of the last visit. 9. Presence of a compatible haploidentical donor (father or mother or sibling). Exclusion Criteria: 1. Patients with a history of poor therapeutic compliance. 2. Patients who, after a psycho-social evaluation, are censored as unsuitable for the procedure. * Socio-familial situation that makes proper participation in the study impossible. * Patients with emotional or psychological problems secondary to the disease, such as post-traumatic stress disorder, phobias, delirium, psychosis, requiring specialist support. * Evaluation of the involvement of family members in the patient's health. * Impossibility to understand information about the trial. 3. Severe functional organ impairment (hepatic, renal, respiratory) (4), according to the criteria of the National Cancer Institute (NCI CTCAE 5.0). 4. Contraindications, interactions, precautions for use and dose reductions indicated in the corresponding data sheets must be considered. 5. Subjects who have been administered other investigational drugs in the 90 days prior to inclusion.