APOA2 and type 2 diabetes mellitus: In contrast, proteins that were downregulated in the serum of PTDM patients compared to the serum of T2DM patients included Apolipoprotein A2 (ApoA2) that may stabilize high‐density lipoprotein (HDL), Apolipoprotein B 100 (ApoB100), that is, a major protein constituent of chylomicrons, LDL, VLDL and Lipoprotein A (LPA).