%0 Journal Article
%T The diagnostic value of extracellular protein kinase A (ECPKA) in serum for gastric and colorectal cancer
%A Junqiang Liu
%A Mengjiao Chen
%A Min Xu
%A Wei Li
%A Yafang Li
%A Yan Wu
%A Yongchang Chen
%J SCIE-indexed Journal
%D 2020
%R 10.21037/tcr-20-764
%X Gastrointestinal cancer, comprising a diverse group of tumors with varying clinical course and prognosis, is one of the most common cancer-related death worldwide due to the high incidence and overall poor outcome. For example, gastric cancer (GC) represents the fifth most common malignancy and remains the third leading cause of cancer mortality with widely varying incidence worldwide, while colorectal cancer (CRC) is the third most common cancer in men and the second most common in women (1). Advances over the last decade in molecular diagnostics in GC and CRC have a benefit to improve our understanding of the complex mechanisms in the development and progression (2). However, the low rate of early diagnosis means that most patients have the advanced-stage disease at diagnosis and so the best surgical window is missed, leading that the 5-year survival rate of patients is extremely low. So, early prediction/detection plays a vital role in improving their prognosis and optimal treatment. Although there is much progress in the cancer diagnosis due to endoscopic ultrasonography application, the early detection of serum biomarkers still has its advantages in patient diagnosis, monitoring, and therapeutic management, compared with some other screening programs (3). It is essential to discover new biomarkers of gastric cancer that could give predictive information about the response to therapy and finally improve the therapeutic outcomes (4). Currently, some serum biomarkers have been identified, including vascular endothelial growth factor, aberrant DNA or RNA, carcinoembryonic antigen (CEA), alpha-fetoprotein (AFP), cancer antigens (i.e., CA125), most of them have already used in the clinic, such as CEA, CA125, and AFP. Unfortunately, the ideal specific biomarker for the prediction of gastrointestinal cancer in the early period remains devoid. Protein Kinase A (PKA), also known as a cAMP-dependent protein kinase, is a serine/threonine kinase that is responsible for phosphorylating a wide range of downstream substrates, the extent of which depends on cellular localization (5-7). PKA is inactive heterotetramers of four regulatory (R) subunits, including RI¦Á, RI¦Â, RII¦Á and RII¦Â, and three catalytic (C) subunits, including C¦Á, C¦Â, and C¦Ã (8). Each R subunit contains a flexible inhibitory segment that limits catalytic activity by blocking access to the active site of the C subunit (8,9). The binding of cAMP to the regulatory subunit leads to the dissociation and activation of the catalytic subunits and thus releases the C subunits to phosphorylate downstream
%U http://tcr.amegroups.com/article/view/40229/html