Diagnostic Value of Tumor-Educated Platelets Integrin Alpha 2b (ITGA2B) and Selectin P (SELP) mRNA Expression in Pancreatic and Biliary Tract Cancer

Malignant tumors arising in the biliary tract and pancreas are aggressive malignancies characterized by a poor prognosis and most of cases are diagnosed at advanced stages and have poor outcome . The most common pancreatic cancer is ductal adenocarcinoma, which accounts for about 80% of all pancreatic cancers. Pancreatic cancer is a highly lethal gastrointestinal cancer with a low 5-year survival rate and difficulty in early detection . Biliary tract cancers can be divided into intrahepatic cholangiocarcinoma, extrahepatic cholangiocarcinoma, and gallbladder cancer. CEA and CA 19-9 are the most common used serum biomarker for cancer screening and the diagnosis of pancreatic and biliary cancer.

Platelets are an essential component of the tumor microenvironment and serve as local and systemic respondents during tumor initiation and tumor metastasis. After interaction with tumor cells or tumor associated biomolecules, platelets can alter their RNA profile, and this process give rise to the so-called tumor educated platelets (TEPs). Tumor cells can directly and indirectly produce changes on platelet RNA and protein content, emerging a new term called liquid biopsy which reflect the presence of cancer and thus give hope to many that they might precede protein markers as a cancer-specific biomarker. Alterations in the TEPs RNA profile have been described as a novel source of potential biomarkers and can be used for early detection of cancer and treatment monitoring. Platelet biomarker transcripts can be transferred from tumor cells to platelets, although in some studies, the putative origin of the biomarker is the megakaryocyte (endogenous).

Integrin Alpha 2b (ITGA2b) gene encodes a member of the integrin alfa chain family of proteins which is proteolytically processed to form subunit of the alpha-IIb/beta-3 integrin cell adhesion receptor which is play crucial role in the blood coagulation system, by mediating platelets aggregation . Selectin P (SELP) gene encodes a protein that is stored in the alpha granules of platelets and Weibel-Palade bodies of endothelial cells. This protein redistributes to the plasma membrane during platelet activation and degranulation and mediates the interaction of activated endothelial cells or platelets with leukocytes. ITGA2b and SELP are cancer related genes and of the mRNA TEPs putative endogenous biomarkers which have a high value for detection of cancer, so, tumor educated platelets (TEPs) broadened the spectrum of liquid biopsy applications, and may enable blood-based cancer diagnostics.