PPA1 and cancer: The overexpressed proteins, including actinin α1 isoform (ACTN1), annexin A5 (ANXA5), cathepsin D (CTSD), F-actin-capping protein subunit β (CAPZB), inorganic pyrophosphatase (PPA1), and tubulin α1c chain (TUBA1C), are related to cellular structure, growth, or cancer cell invasion (Table 1).