The high NBCn1 TOR value of ~15,000 s−1 (Supplementary Table 3), provides breast cancer cells with an additional survival advantage in that mediating a given rate of cellular base influx theoretically would require fewer plasma membrane NBCn1 transporters, thereby lowering the energy expenditure utilized in the processes of transporter synthesis and degradation. The gene discussed is SLC4A7; the disease is breast cancer.