The extracellular matrix (ECM) is a complex network of diverse multidomain macromolecules, including collagen, proteoglycans, and fibronectin, that significantly contribute to the mechanical properties of tissues. Matricellular proteins (MCPs), as a family of non-structural proteins, play a crucial role in regulating various ECM functions. They exert their biological effects by interacting with matrix proteins, cell surface receptors, cytokines, and proteases. These interactions govern essential cellular processes such as differentiation, proliferation, adhesion, migration as well as multiple signal transduction pathways. Consequently, MCPs are pivotal in maintaining tissue homeostasis while orchestrating intricate molecular mechanisms within the ECM framework. The expression level of MCPs in adult steady-state tissues is significantly low; however, under pathological conditions such as inflammation and cancer, there is a substantial increase in their expression. In recent years, an increasing number of studies have focused on elucidating the role and significance of MCPs in the development and progression of head and neck cancer (HNC). During HNC progression, there is a remarkable upregulation in MCP expression. Through their distinctive structure and function, they actively promote tumor growth, invasion, epithelial-mesenchymal transition, and lymphatic metastasis of HNC cells. Moreover, by binding to integrins and modulating various signaling pathways, they effectively execute their biological functions. Furthermore, MCPs also hold potential as prognostic indicators. Although the star proteins of various MCPs have been extensively investigated, there remains a plethora of MCP family members that necessitate further scrutiny. This article comprehensively examines the functionalities of each MCP and highlights the research advancements in the context of HNC, with an aim to identify novel biomarkers for HNC and propose promising avenues for future investigations.

Tumor progression from an expanded cell population in a primary location to disseminated lethal growths subverts attempts at cures. It has become evident that these steps are driven in a large part by cancer cell-extrinsic signaling from the tumor microenvironment (TME), one cellular component of which is becoming more appreciated for potential modulation of the cancer cells directly and the TME globally. That cell is a heterogenous population referred to as adult mesenchymal stem cells/multipotent stromal cells (MSCs). Herein, we review emerging evidence as to how these cells, both from distant sources, mainly the bone marrow, or local resident cells, can impact the progression of solid tumors. These nascent investigations raise more questions than they answer but paint a picture of an orchestrated web of signals and interactions that can be modulated to impact tumor progression.

To quantify levels of matricellular proteins in aqueous humor samples from acute primary angle closure (APAC) and non-glaucomatous cataract eyes and investigate their correlation with intraocular pressure (IOP) fluctuation.
Aqueous humor samples were collected from 63 eyes including 29 current APAC eyes, 12 previous APAC eyes, and 22 cataract eyes. Concentrations of four main matricellular proteins (SPARC, tenascin-C, thrombospondin-2, and osteopontin) were measured using multiplexed immunoassay kits. Correlations between matricellular proteins and age, sex, and IOP were then detected using Spearman\'s rank correlation coefficient.
The levels of SPARC, thrombospondin-2, and osteopontin were significantly elevated in the APAC group as compared to the cataract group (p < 0.001, p < 0.001, and p = 0.009, respectively). Further separation of the APAC group into current and previous APAC groups showed that only the differences of SPARC and thrombospondin-2 between the current APAC and cataract groups were significant (both p < 0.001). All four matricellular proteins were found to have a positive correlation with IOP in the current APAC group but no correlation was found in the previous APAC or cataract groups.
The levels of matricellular proteins were significantly elevated in the current APAC eyes and positively correlated to IOP. Further studies are necessary to investigate the molecular mechanisms and histological evidence of pathogenesis in matricellular proteins in APAC.

Cardiac fibrosis, characterized by excessive deposition of extracellular matrix (ECM) proteins in the myocardium, distorts the architecture of the myocardium, facilitates the progression of arrhythmia and cardiac dysfunction, and influences the clinical course and outcome in patients with heart failure. This review describes the composition and homeostasis in normal cardiac interstitial matrix and introduces cellular and molecular mechanisms involved in cardiac fibrosis. We also characterize the ECM alteration in the fibrotic response under diverse cardiac pathological conditions and depict the role of matricellular proteins in the pathogenesis of cardiac fibrosis. Moreover, the diagnosis of cardiac fibrosis based on imaging and biomarker detection and the therapeutic strategies are addressed. Understanding the comprehensive molecules and pathways involved in ECM homeostasis and remodeling may provide important novel potential targets for preventing and treating cardiac fibrosis.