CA9 and cancer: To check if the model is supported by the transcriptomic data being analyzed in our study, we note that (1) three membrane-associated CAs (CA9, CA12, CA14) show up-regulation in five out of six cancer types (except for prostate cancer), as shown Figure 2; and (2) two of the three NBC genes, NBC2 (SLC4A5) and NBC3 (SLC4A7), show up-regulation in four cancer types.