Fas apoptotic inhibitory molecule 2 (FAIM2) is an important member of the transmembrane BAX inhibitor motif containing (TMBIM) family. It is involved in multiple biological processes such as apoptosis regulation, with its expression being associated with the Fas-apoptosis pathway. FAIM2 also seems to be linked to various cellular functions including cell survival and differentiation, and thus is of significance in understanding normal biological function and disease mechanisms [2,4,6].

In medulloblastoma, the expression of FAIM2 was decreased in metastatic samples, and its low expression was associated with poor prognosis. Pan-cancer analysis showed that FAIM2 was down-regulated in most tumors, and high expression was related to better prognosis in several cancers. In non-small cell lung cancer, high FAIM2 expression was positively associated with tumor stage, lymph node metastasis, bone metastasis, and poor prognosis, and it promoted cell growth and bone metastasis by activating the Wnt/β-catenin pathway. In facioscapulohumeral muscular dystrophy, DUX4 leads to reduced FAIM2 levels, and FAIM2 overexpression can rescue myogenic differentiation defects. In transient brain ischemia, up-regulation of Faim2 may contribute to the neuroprotective effects of low-dose erythropoietin. In neurofibromatosis type 1, miR-612 targeted FAIM2 to regulate cellular activities. In colorectal adenocarcinoma, FAIM2 was up-regulated. In oral squamous cell carcinoma, FAIM2 was down-regulated in 61.0% of samples. In small-cell lung cancer and atypical carcinoid, FAIM2 was significantly overexpressed and could be a diagnostic marker and therapeutic target [1,2,3,4,5,6,7,8,9].

In conclusion, FAIM2 has diverse functions in different biological processes and diseases. Studies, though not specifically relying on KO/CKO mouse models in the provided references, have shown its significance in cancer metastasis, prognosis, myogenesis, and neuroprotection. Understanding FAIM2 could potentially offer new insights into disease mechanisms and therapeutic strategies for various conditions such as cancer, muscular dystrophy, and ischemic stroke.

References:

1. Zhou, Xiaojun, Zhao, Hao. . FAIM2 is correlated with metastasis of medulloblastoma through bioinformatics analysis. In Medicine, 102, e33591. doi:10.1097/MD.0000000000033591. https://pubmed.ncbi.nlm.nih.gov/37083768/

2. Cai, Jiayang, Ye, Zhang, Hu, Yuanyuan, Yang, Ji'an, Chen, Qianxue. 2022. FAIM2 is a potential pan-cancer biomarker for prognosis and immune infiltration. In Frontiers in oncology, 12, 998336. doi:10.3389/fonc.2022.998336. https://pubmed.ncbi.nlm.nih.gov/36185230/

3. She, Kelin, Yang, Wensheng, Li, Mengna, Xiong, Wei, Zhou, Ming. 2021. FAIM2 Promotes Non-Small Cell Lung Cancer Cell Growth and Bone Metastasis by Activating the Wnt/β-Catenin Pathway. In Frontiers in oncology, 11, 690142. doi:10.3389/fonc.2021.690142. https://pubmed.ncbi.nlm.nih.gov/34568020/

4. Soliman, Hossam A N, Toso, Erik A, Darwish, Inas E, Ali, Samia M, Kyba, Michael. 2022. Antiapoptotic Protein FAIM2 is targeted by miR-3202, and DUX4 via TRIM21, leading to cell death and defective myogenesis. In Cell death & disease, 13, 405. doi:10.1038/s41419-022-04804-x. https://pubmed.ncbi.nlm.nih.gov/35468884/

5. Komnig, Daniel, Gertz, Karen, Habib, Pardes, Falkenburger, Björn H, Reich, Arno. 2018. Faim2 contributes to neuroprotection by erythropoietin in transient brain ischemia. In Journal of neurochemistry, 145, 258-270. doi:10.1111/jnc.14296. https://pubmed.ncbi.nlm.nih.gov/29315561/

6. Wang, Meng, Wang, Zengtao, Zhu, Xiaolei, Guan, Shibing, Liu, Zhibo. 2019. NFKB1-miR-612-FAIM2 pathway regulates tumorigenesis in neurofibromatosis type 1. In In vitro cellular & developmental biology. Animal, 55, 491-500. doi:10.1007/s11626-019-00370-3. https://pubmed.ncbi.nlm.nih.gov/31197610/

7. Ziaee, Farinaz, Hajjari, Mohammadreza, Kazeminezhad, Reza Seyed, Behmanesh, Mehrdad. . SNHG7 and FAIM2 are up-regulated and co-expressed in colorectal adenocarcinoma tissues. In Klinicka onkologie : casopis Ceske a Slovenske onkologicke spolecnosti, 33, 445-449. doi:. https://pubmed.ncbi.nlm.nih.gov/33685194/

8. Hartanto, Firstine Kelsi, Karen-Ng, Lee Peng, Vincent-Chong, Vui King, Tay, Keng Kiong, Zain, Rosnah Binti. . KRT13, FAIM2 and CYP2W1 mRNA expression in oral squamous cell carcinoma patients with risk habits. In Asian Pacific journal of cancer prevention : APJCP, 16, 953-8. doi:. https://pubmed.ncbi.nlm.nih.gov/25735388/

9. Kang, Hio Chung, Kim, Jong In, Chang, Hee Kyung, Jablons, David M, Kim, Il-Jin. 2016. FAIM2, as a novel diagnostic maker and a potential therapeutic target for small-cell lung cancer and atypical carcinoid. In Scientific reports, 6, 34022. doi:10.1038/srep34022. https://pubmed.ncbi.nlm.nih.gov/27677402/