The a2 isoform of the V0 a‐subunit of V‐ATPase (a2V) is highly expressed in breast (Ibrahim et al., 2015; Katara et al., 2014; Pamarthy et al., 2015) and ovarian (Kulshrestha et al., 2015, 2016) cancer, specifically on the cell membrane of cancer cells (Ibrahim et al., 2015; Kulshrestha et al., 2015; Pamarthy et al., 2015). Here, ATP6V0A2 is linked to cancer.