An automated microfluidic electrochemiluminescence device was used for accurate, sensitive measurements of specific tumor markers including: Prostate specific antigen (PSA), hepatocellular carcinoma Alpha-fetoprotein (AFP) tumor marker, breast cancer antigen (CA153), colon cancer antigen (CEA), gastric carcinoma (CA724) tumor maker, ovarian cancer (CA125) tumor marker, and pancreas carcinoma (CA199) tumor marker in plasma and exosome. The gene discussed is KLK3; the disease is gastric carcinoma.