NPPA and primary systemic amyloidosis: The localization in the cisternae of the endoplasmic reticulum is more frequent in systemic amyloidosis where misfolded and polymerized proteins accumulate in producing cell, such as B lymphocyte/plasma cell (antibody light chain), pancreatic islet β-cell (insulin), and atrial myocardiocyte (ANF or atrial natriuretic factor) (Figure 3) [16].