TTR and ovarian cancer: Notably, OVA1® is a United States (US) Food and Drug Administration (FDA) approved test, which includes apolipoprotein A-I (APOA1), transthyretin (TTR), transferrin (TF), β2-microglobulin (B2M), along with MUC16, and has demonstrated effectiveness in detecting early-stage ovarian cancer (Zamanian-Daryoush and DiDonato, 2015).