Importantly, a work showed that breast cancer spheroids originating from patient-derived xenografts (PDXs) exhibited similar Ki-67 and caspase-3 expression when compared with the patient’s original tumor and fresh PDX tumor than traditional 2D culture [78], showing again that 3D culture better recapitulates the tumor characteristics of experimental models and from patients. The gene discussed is CASP3; the disease is breast carcinoma.