Serum Biomarker Study for the Prognosis of Patients With Hepatocellular Carcinoma and Esophageal Cancer Undergoing Radiotherapy Using Multiplex Proximity Ligation Assay

There have been many biomarkers, such as angiogenesis factors and cytokines, related to cancer progression or microenvironment interaction. However, the commonly used enzyme-linked immunosorbent assay (ELISA) requires the certain volume of each sample for specific antigen or antibody. It may not be practically efficient to test a broad spectrum of biomarkers with limited volumes of serum from cancer patients. Proximity ligation assay (PLA), an established concept and platform requiring very little sample volume to quantitatively detect a variety of biomarkers, is being developed with multiplex versions of improved sensitivity and dynamic range by the Stanford group. From the three completed trials ("In vivo/vitro radiation-induced liver disease in HBV carrier（9261700196）", "Bystander effect study of radiation-induced viral hepatitis B reactivation（9261700196）", and "Pre- and post-chemoradiation blood RNA-microarray analysis to predict response and outcome of locally advanced esophageal squamous cell carcinoma（200805061R）") and one ongoing trial ("A phase I dose escalation trial of conformal hypofractionated radiation therapy for patients with hepatitis B virus-related Child A cirrhosis and hepatocellular carcinoma（200906051R）"), we have collected the pre-treatment and post-treatment serum samples of patients with hepatocellular carcinoma undergoing definitive radiotherapy and patients with esophageal cancer undergoing neoadjuvant chemoradiotherapy. Altered patterns of failure for post-radiotherapy hepatocellular carcinoma, especially intrahepatic and extrahepatic metastasis, and treatment response for post-chemoradiotherapy esophageal cancer upon esophagectomy, demands the effective biomarkers for the early prediction and appropriate management. The limited sample volumes form the obstacle of testing adequate number of biomarkers by ELISA. In this study we plan to collaborate with the Stanford group, to send and process these samples (100 μL each) to measure the dynamic changes of up to 56 or more biomarkers. We try to find the potential biomarkers correlating with treatment responses and patterns of failure for the future clinical practice, and wish to set up this viable PLA platform in our institute through this collaboration.