ROAD-1

CD74 (MHC class II invariant chain, Ii) is a non-polymorphic type II transmembrane glycoprotein. It is clear that, in addition to be an MHC class II chaperone, CD74 has a diversity of biological functions in physiological and pathological situations. CD74 also participates in other non-MHC II protein trafficking, such as angiotensin II type I receptor. In addition, CD74 is a cell membrane high-affinity receptor for macrophage migration inhibitory factor (MIF), D-dopachrome tautomerase (D-DT/MIF-2) and bacterial proteins. CD74 also regulates T-cell and B-cell developments, dendritic cell (DC) motility, macrophage inflammation, and thymic selection. The activation of receptor complex CD74/CD44 may lead to multiple intracellular signal pathways, such as the activation of the extracellular signal regulated kinase (ERK) 1 and 2, the PI3K-Akt signal transduction cascade, NFκB, and the AMP-activated protein kinase (AMPK) pathway. CD74 plays important roles in many inflammatory diseases, such as liver fibrosis, type I diabetes, systemic lupus erythematosus, and Alzheimer disease. In this study, we will focus on the immunological functions of CD74 molecules and its roles in immune-relevant disorders.

Gastric cancer is a deadly disease and remains the third leading cause of cancer-related death worldwide. The 5-year overall survival rate of patients with early-stage localized gastric cancer is more than 60%, whereas that of patients with distant metastasis is less than 5%. Surgical resection is the best option for early-stage gastric cancer, while chemotherapy is mainly used in the middle and advanced stages of this disease, despite the frequently reported treatment failure due to chemotherapy resistance. Therefore, there is an unmet medical need for identifying new biomarkers for the early diagnosis and proper management of patients, to achieve the best response to treatment. Long non-coding RNAs (lncRNAs) in body fluids have attracted widespread attention as biomarkers for early screening, diagnosis, treatment, prognosis, and responses to drugs due to the high specificity and sensitivity. In the present review, we focus on the clinical potential of lncRNAs as biomarkers in liquid biopsies in the diagnosis and prognosis of gastric cancer. We also comprehensively discuss the roles of lncRNAs and their molecular mechanisms in gastric cancer chemoresistance as well as their potential as therapeutic targets for gastric cancer precision medicine.

Urea is generated by the urea cycle enzymes, which are mainly in the liver but are also ubiquitously expressed at low levels in other tissues. The metabolic process is altered in several conditions such as by diets, hormones, and diseases. Urea is then eliminated through fluids, especially urine. Blood urea nitrogen (BUN) has been utilized to evaluate renal function for decades. New roles for urea in the urinary system, circulation system, respiratory system, digestive system, nervous system, etc., were reported lately, which suggests clinical significance of urea.