SLC4A2 and ovarian serous carcinoma: When a minimum peptide number of 3 was set as additional selection criterion, a total of 27 differentially expressed proteins was found (13 up-regulated and 14 down-regulated) (Tables 1 and 2), among which the up-regulation of Anion exchange protein 2 (AE2) was confirmed by analyzing The Cancer Genome Atlas (TCGA) gene expression microarray datasets from ovarian serous carcinomas (Fig. 1A).