FJX1, also known as four-jointed box kinase 1, is a planar cell polarity (PCP) protein and a member of the Fat/Dchs/FJX1 PCP complex. It is a non-receptor Ser/Thr protein kinase that phosphorylates Fat1 in the Golgi system, regulating its extracellular deposition. FJX1 is expressed in various tissues including the nervous system, epithelial cells of multiple organs, and during limb development. It may function as a secreted signaling molecule and has been associated with the Notch signaling pathway [3,4].

In cancer research, FJX1 shows potential as a diagnostic and prognostic biomarker. In colorectal cancer, it can predict overall survival, and serum FJX1 levels are sensitive and specific in differentiating patients from controls, being associated with distant metastasis and decreasing after surgery [1]. In gastric cancer, its overexpression promotes cell proliferation via the PI3K/AKT signaling pathway and is associated with poor prognosis [2]. In colon adenocarcinoma, it acts as an oncogene, regulated by miR-532-3p, and promotes cell malignant behaviors [5]. In nasopharyngeal carcinoma, FJX1 promotes cell proliferation, anchorage-dependent growth, and cellular invasion [6].

In conclusion, FJX1 has significant functions in cell regulation and is closely associated with cancer development and progression. Its role as a biomarker and its involvement in cancer-related signaling pathways make it a potential target for cancer diagnosis, prognosis, and treatment. Studies on FJX1 enhance our understanding of cancer biology and may offer new strategies for cancer management.

References:

1. Liu, Lei, Huang, Yecai, Li, Yan, Sun, Xiaobin, Guo, Yuanbiao. 2022. FJX1 as a candidate diagnostic and prognostic serum biomarker for colorectal cancer. In Clinical & translational oncology : official publication of the Federation of Spanish Oncology Societies and of the National Cancer Institute of Mexico, 24, 1964-1974. doi:10.1007/s12094-022-02852-5. https://pubmed.ncbi.nlm.nih.gov/35650386/

2. Zhang, H, Zhang, Z, Wang, Q, Li, J, Zuo, L. . [FJX1 overexpression is associated with poor prognosis and promotes gastric cancer proliferation via the PI3K/AKT signaling pathway]. In Nan fang yi ke da xue xue bao = Journal of Southern Medical University, 43, 975-984. doi:10.12122/j.issn.1673-4254.2023.06.13. https://pubmed.ncbi.nlm.nih.gov/37439170/

3. Bu, Tiao, Li, Xinyao, Wang, Lingling, Sun, Fei, Cheng, C Yan. 2023. Regulation of Sertoli cell function by planar cell polarity (PCP) protein Fjx1. In Molecular and cellular endocrinology, 571, 111936. doi:10.1016/j.mce.2023.111936. https://pubmed.ncbi.nlm.nih.gov/37119967/

4. Rock, Rebecca, Heinrich, Achim C, Schumacher, Nina, Gessler, Manfred. . Fjx1: a notch-inducible secreted ligand with specific binding sites in developing mouse embryos and adult brain. In Developmental dynamics : an official publication of the American Association of Anatomists, 234, 602-12. doi:. https://pubmed.ncbi.nlm.nih.gov/16145673/

5. Cheng, Tao, Zhu, Xiyuan, Lu, Jiying, Teng, Xianglong. 2022. MiR-532-3p suppresses cell proliferation, migration and invasion of colon adenocarcinoma via targeting FJX1. In Pathology, research and practice, 232, 153835. doi:10.1016/j.prp.2022.153835. https://pubmed.ncbi.nlm.nih.gov/35278814/

6. Chai, San Jiun, Ahmad Zabidi, Muhammad Mamduh, Gan, Siew Pey, Patel, Vyomesh, Cheong, Sok Ching. 2019. An Oncogenic Role for Four-Jointed Box 1 (FJX1) in Nasopharyngeal Carcinoma. In Disease markers, 2019, 3857853. doi:10.1155/2019/3857853. https://pubmed.ncbi.nlm.nih.gov/31236144/