Glucose-Regulated Protein 78 (GRP78) is a chaperone protein that is predominantly expressed in the lumen of the endoplasmic reticulum. GRP78 plays a crucial role in protein folding by assisting in the assembly of misfolded proteins. Under cellular stress conditions, GRP78 can translocate to the cell surface (csGRP78) were it interacts with different ligands to initiate various intracellular pathways. The expression of csGRP78 has been associated with tumor initiation and progression of multiple cancer types. This review provides a comprehensive analysis of the existing evidence on the roles of GRP78 in various types of cancer and other human pathology. Additionally, the review discusses the current understanding of the mechanisms underlying GRP78\'s involvement in tumorigenesis and cancer advancement. Furthermore, we highlight recent innovative approaches employed in downregulating GRP78 expression in cancers as a potential therapeutic target.

GRP78 is a chaperone with anti-apoptotic function associated with aggressive tumors. This systematic review aimed to evaluate GRP78 expression in cancer and its relation to prognosis outcomes. This review was conducted in different databases searching for human cancer studies assessing GRP78 immunohistochemical levels on tissue samples. A total of 98 manuscripts were included. In 62% of the studies, GRP78 was associated with a worse prognosis. A meta-analysis included 29 studies that detected a significantly higher expression of GRP78 in cancer tissues (RR= 2.35, 95% CI 1.75-3.15) compared to control. A meta-analysis of 3 and 5-years Overall Survival revealed an increased risk of death for tumors with high expression of GRP78 (RR=1.36, 95%CI 1.16-1,59, I2 = 57%) and (RR=1.65, 95%CI 1.22-2.21, I2 =64%), respectively. GRP78 is an important prognostic biomarker for different types of cancer and a promising therapeutic target.

The pathophysiology of coronavirus disease 2019 (COVID‑19) is mainly dependent on the underlying mechanisms that mediate the entry of severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2) into the host cells of the various human tissues/organs. Recent studies have indicated a higher order of complexity of the mechanisms of infectivity, given that there is a wide‑repertoire of possible cell entry mediators that appear to co‑localise in a cell‑ and tissue‑specific manner. The present study provides an overview of the \'canonical\' SARS‑CoV‑2 mediators, namely angiotensin converting enzyme 2, transmembrane protease serine 2 and 4, and neuropilin‑1, expanding on the involvement of novel candidates, including glucose‑regulated protein 78, basigin, kidney injury molecule‑1, metabotropic glutamate receptor subtype 2, ADAM metallopeptidase domain 17 (also termed tumour necrosis factor‑α convertase) and Toll‑like receptor 4. Furthermore, emerging data indicate that changes in microRNA (miRNA/miR) expression levels in patients with COVID‑19 are suggestive of further complexity in the regulation of these viral mediators. An in silico analysis revealed 160 candidate miRNAs with potential strong binding capacity in the aforementioned genes. Future studies should concentrate on elucidating the association between the cellular tropism of the SARS‑CoV‑2 cell entry mediators and the mechanisms through which they might affect the clinical outcome. Finally, the clinical utility as a biomarker or therapeutic target of miRNAs in the context of COVID‑19 warrants further investigation.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal types of tumours, and its incidence is rising worldwide. Although survival can be improved by surgical resection when these tumours are detected at an early stage, this cancer is usually asymptomatic, and disease only becomes apparent after metastasis. Several risk factors are associated with this disease, the most relevant being chronic pancreatitis, diabetes, tobacco and alcohol intake, cadmium, arsenic and lead exposure, certain infectious diseases, and the mutational status of some genes associated to a familial component. PDAC incidence has increased in recent decades, and there are few alternatives for chemotherapeutic treatment. Endoplasmic reticulum (ER) stress factors such as GRP78/BiP (78 kDa glucose-regulated protein), ATF6α (activating transcription factor 6 isoform α), IRE1α (inositol-requiring enzyme 1 isoform α), and PERK (protein kinase RNA-like endoplasmic reticulum kinase) activate the transcription of several genes involved in both survival and apoptosis. Some of these factors aid in inducing a non-proliferative state in cancer called dormancy. Modulation of endoplasmic reticulum stress could induce dormancy of tumour cells, thus prolonging patient survival. In this systematic review, we have compiled relevant results concerning those endoplasmic reticulum stress factors involved in PDAC, and we have analysed the mechanism of dormancy associated to endoplasmic reticulum stress and its potential use as a chemotherapeutic target against PDAC.