Patients with tuberous sclerosis (TSC) may develop disease in multiple organs, with children under 20 years of age more likely to develop brain tumors (subventricular giant cell astrocytoma, SEGA), and adult patients may develop tumors of the lungs and kidneys, which affect the patient’s quality of life and may also lead to life-threatening conditions. There is no effective way to predict what tumors will develop in the future in a patient with tuberous sclerosis, so are there drugs that might reduce the likelihood of the patient developing them? Polish physician Kotulska et al. conducted a clinical trial of identical twins, both with SEGA combined with TSC, in which both sisters had the same genetic expression and also shared a mutation at the same locus (TSC2). Starting at age 4, one was given rapamycin and the other a placebo. After 24 months, the patient on rapamycin was stable, with a significant reduction in the size of the SEGA tumor and no renal or skin lesions of TSC, while the patient on placebo had angiofibroma of the face and angiomyolipoma of the kidney, although the brain tumor remained stable. TSC organ diseases appear progressively with age, but in a single TSC patient, the clinician cannot accurately predict his (or her) development. Clinicians are unable to predict exactly what diseases will occur later in life. Moreover, TSC is relatively rare, and it may be difficult to organize a large population of patients currently taking rapamycin to compare the prognosis of patients taking the drug after 10 or 20 years, and the population of patients taking placebo over time. This clinical control illustrates the problem well, as the two sisters are identical and have the same locus mutation, and taking rapamycin delays the progression of the disease very well and suggests that the drug has a preventive effect on tuberous sclerosis. However, the patient must decide whether to take the drug based on his or her own situation to make a comprehensive decision, after all, there is no large-scale case follow-up of prolonged use of the drug, which is an immunosuppressant, and it is inconclusive whether prolonged use will lead to the development of other malignant tumors in patients.