In our study, the most highly expressed gene in leiomyoma likely to be growing and those more likely to be non-growing (leiomyoma from older blacks vs. from older whites) was a muscle specific cytoplasmic carbonic anhydrase (CAIII), an enzyme which serves to buffer the cellular acid-base balance (pH regulation) (reviewed in Breton et al., 2001 [13]). Here, CA3 is linked to leiomyoma.