| Aspect | Summary | Key sources with publication date and URL |
|---|---|---|
| Identity/Family | **EPYC** encodes **epiphycan** (human UniProt **Q99645**), a **small leucine-rich proteoglycan (SLRP)** carrying **dermatan sulfate and/or chondroitin sulfate (DS/CS)** chains; reviewed as an ECM proteoglycan at **12q21.33**. Open Targets also maps the approved symbol **EPYC** to disease associations including osteoarthritis and skeletal-system abnormalities, supporting correct human gene identity. (pqac-00000001, pqac-00000002, pqac-00000000) | Hayes et al., **2018** — https://doi.org/10.1042/bcj20170820; Halari et al., **2021** — https://doi.org/10.3390/ijms221910584; Open Targets context (pqac-00000000) |
| Domains/structure | EPYC is an **SLRP with leucine-rich repeats (LRRs)**; the cited review notes epiphycan contains **7 LRRs**, fewer than the **10–11 LRRs** typical of many other SLRPs. SLRPs share a core LRR-rich protein architecture with extracellular matrix structural roles. (pqac-00000001, pqac-00000002) | Hayes et al., **2018** — https://doi.org/10.1042/bcj20170820; Halari et al., **2021** — https://doi.org/10.3390/ijms221910584 |
| Localization | Evidence supports EPYC as a **secreted/extracellular matrix proteoglycan**. Reviews place SLRPs in the ECM, and 2024 laryngeal-cancer work explicitly treats EPYC as a **soluble/secreted ECM-associated SLRP** acting on endothelial/tumor microenvironment signaling; GO/KEGG enrichment linked EPYC-containing signatures to **extracellular matrix organization**, **extracellular region**, and **ECM-receptor interaction**. (pqac-00000002, pqac-00000004, pqac-00000005) | Halari et al., **2021** — https://doi.org/10.3390/ijms221910584; Zhou et al., **2024** — https://doi.org/10.21203/rs.3.rs-4182627/v1 |
| Core biological role | Current evidence supports a primary **structural ECM role in cartilage**, especially **collagen fibrillogenesis / fibril formation** and cartilage matrix maturation. Reviews identify EPYC as a cartilage SLRP; chondrogenic human MSC cultures show EPYC appearing during **matrix maturation** and being characteristic of a more mature **articular-cartilage-like matrix**. A 2024 pancreatic-cancer study reiterates that EPYC **regulates fibril formation by interacting with collagen fibrils and other ECM proteins**. (pqac-00000001, pqac-00000010, pqac-00000006) | Hayes et al., **2018** — https://doi.org/10.1042/bcj20170820; Sorrell et al., **2018** — https://doi.org/10.1002/jor.23820; Yang et al., **2024** — https://doi.org/10.1038/s41598-024-51478-w |
| Key tissues/cell types | EPYC is reported in **epiphyseal/growth plate cartilage** and cartilage-forming cells. Review evidence places epiphycan in **epiphyseal cartilage**; human MSC chondrogenesis links EPYC to **articular-cartilage-type matrix maturation**; mouse work found **Epyc specifically expressed in growth plate chondrocytes and absent from articular chondrocytes/perichondrial cells** in that model; separate cartilage transcriptomics showed strong **downregulation in articular cartilage** under disease-model conditions. (pqac-00000009, pqac-00000010, pqac-00000007, pqac-00000008) | Hayes et al., **2018** — https://doi.org/10.1042/bcj20170820; Sorrell et al., **2018** — https://doi.org/10.1002/jor.23820; Otsuru et al., **2024** — https://doi.org/10.21203/rs.3.rs-4656728/v1; Westermann et al., **2020** — https://doi.org/10.1242/dmm.046425 |
| Pathways/signaling links | Native/cartilage biology evidence mainly supports ECM assembly roles rather than enzymatic catalysis. In 2024 cancer studies, EPYC was linked to **PI3K-AKT** signaling in pancreatic cancer and to **Wnt/Axin/β-catenin** plus **VEGFR1/VEGF** signaling in laryngeal cancer. The laryngeal study further reported **direct EPYC–VEGFR1 binding** and VEGFR1 degradation, consistent with extracellular signaling modulation by a secreted matrix proteoglycan. (pqac-00000006, pqac-00000003, pqac-00000004, pqac-00000015) | Yang et al., **2024** — https://doi.org/10.1038/s41598-024-51478-w; Zhou et al., **2024** — https://doi.org/10.21203/rs.3.rs-4182627/v1 |
| Disease/biomarker evidence (2023-2024) | Recent studies propose EPYC as a **biomarker/functional contributor** in several diseases: **pancreatic cancer** prognostic biomarker with functional proliferation effects; **laryngeal cancer** angiogenesis/carcinogenesis promoter; **breast cancer** diagnostic biomarker candidate; Open Targets lists associations with **osteoarthritis**, **abnormality of the skeletal system**, and **hip dysplasia, Beukes type**. These disease links are promising but context-dependent and do not supersede EPYC’s likely core ECM/cartilage function. (pqac-00000006, pqac-00000004, pqac-00000011, pqac-00000000) | Yang et al., **2024** — https://doi.org/10.1038/s41598-024-51478-w; Zhou et al., **2024** — https://doi.org/10.21203/rs.3.rs-4182627/v1; Golestan et al., **2024** — https://doi.org/10.1186/s12885-024-11913-7; Open Targets context (pqac-00000000) |
| Quantitative stats (2024) | Reported 2024 quantitative findings include: breast cancer **qRT-PCR in 55 paired samples** showed EPYC upregulation (**P < 0.0001**), but overall-survival association was weak/non-significant (**HR 1.04, log-rank P = 0.72**). Pancreatic-cancer prognostic modeling reported **c-index 0.72** (training) and **0.70** (test) in a model retaining EPYC. Laryngeal-cancer work reported **EPYC coefficient = 0.25** in its risk score and **EPYC–VEGFR1 binding KD ~44.1 µM**. In cartilage disease-model tissue, **Epyc log2 ratio ~ -4** in hip articular cartilage was reported. (pqac-00000011, pqac-00000012, pqac-00000013, pqac-00000003, pqac-00000008) | Golestan et al., **2024** — https://doi.org/10.1186/s12885-024-11913-7; Yang et al., **2024** — https://doi.org/10.1038/s41598-024-51478-w; Zhou et al., **2024** — https://doi.org/10.21203/rs.3.rs-4182627/v1; Westermann et al., **2020** — https://doi.org/10.1242/dmm.046425 |


*Table: This table summarizes the verified identity, structure, localization, biological role, tissue expression, signaling links, and recent disease evidence for human EPYC (epiphycan). It is useful as a compact evidence map for functional annotation grounded in the cited contexts only.*