Ultimately, this yielded 99.7 ± 0.3% CD19+ yeast cells, clearly exemplified by the PTDH3 promoter, thus closely resembling the phenotype of the cancer benchmark CD19+ NALM6 B-cell leukemia cell line (100 ± 0% CD19+ ) (Fig. 2, Supplementary Fig. 1). The gene discussed is CD19; the disease is cancer.