Qsox1, or quiescin sulfhydryl oxidase 1, is an enzyme that oxidizes thiols during protein folding, reducing molecular oxygen to hydrogen peroxide [6]. It is involved in various cellular processes, such as disulfide bond formation, redox homeostasis, and may be associated with multiple pathways. Its biological importance spans across different physiological and pathological conditions, making genetic models crucial for studying its functions.

In NSCLC, aberrant m5C hypermethylation via the NSUN2-YBX1-QSOX1 axis mediates intrinsic resistance to gefitinib [1]. In esophageal cancer, QSOX1 promotes PD-L1 upregulation and CD8 T cell exclusion in dormant cancer stem cells, facilitating immune escape [2]. In the colon, QSOX1 knockout mice have impaired mucus barrier function due to decreased sialic acid in the gut mucus glycome, as QSOX1 forms regulatory disulfides in Golgi glycosyltransferases [3]. In preeclampsia, QSOX1 is overexpressed in the placenta, and its knockdown attenuates trophoblast apoptosis and intracellular hydrogen peroxide levels [4]. In renal cell carcinoma, the inhibitor SBI-183, which targets QSOX1 enzymatic activity, suppresses tumor growth in xenograft mouse models [5].

In conclusion, Qsox1 plays diverse and significant roles in multiple biological processes and disease conditions. Gene knockout or knockdown models, like in the cases of NSCLC, esophageal cancer, colon function, preeclampsia, and renal cell carcinoma, have revealed its importance in drug resistance, immune escape, mucosal barrier maintenance, trophoblast apoptosis, and tumor growth regulation. Understanding Qsox1 functions through these models provides insights into disease mechanisms and potential therapeutic targets.