After three weeks of BLM-free culturing, three of the originally resistant sub-clones (including both testicular cell lines NT20.1, NCCIT1.5 and the lung cancer cell line HOP0.05) exhibited a significant IC50 reduction (Figure 3) and doubling time reduction (Figure 4), when compared to regularly maintained BLM-resistant sub-clones. The gene discussed is BLM; the disease is lung carcinoma.