As　a　widely　distributed　RNA　methylation　modification,　m5C　is　involved　in　the　regulation　of　tumorigenesis.　Nevertheless,　its　fundamental　process　is　not　clear.　This　research　sought　to　examine　the　genetic　properties　of　the　5-methylcytosine　(m5C)　regulator　in　endometrial　carcinoma,　as　well　as　the　prognostic　significance　and　impact　of　m5C　regulators　on　oxidative　stress.　Therefore,　the　TCGA-UCEC　data　set　was　used　to　explore　the　characteristics　of　17　RNAm5C-related　genes　in　the　transcriptome,　genome,　and　regulatory　network.　The　subtypes　of　RNAm5C　in　UCEC　were　identified　based　on　the　expression　levels　of　17　RNAm5C-related　genes.　The　prognosis　of　RNAm5C-2　was　significantly　better　than　that　of　RNAm5C-1.　Then,　we　examined　the　differences　(variations)　across　various　subtypes　in　terms　of　immune　cell　infiltration　(ICI)　as　well　as　the　expression　of　immune-related　signal　markers.　The　findings　demonstrated　that　there　were　distinct　variations　in　the　infiltration　level　of　immune　cells　in　each　subtype,　which　may　be　the　reason　for　the　differences　in　the　prognosis　of　each　subtype.　In　addition,　the　differentially　expressed　genes　(DEGs)　among　RNAm5C　subtypes　of　different　UCEC　tumors　were　identified,　and　the　DEGs　significant　for　survival　were　screened.　After　obtaining　34　prognostic　genes,　the　dimensionality　was　reduced　to　construct　an　RNA　methylation　score　(RS).　As　per　the　findings,　RS　is　a　more　accurate　marker　for　determining　the　prognosis　for　patients　with　endometrial　cancer.　The　RS　was　used　to　categorize　UCEC　tumor　samples,　and　these　results　led　to　the　formation　of　high-score　and　low-score　groups.　The　patients　in　the　group　with　a　high-RNA　methylation　score　exhibited　a　survival　time　that　was　considerably　longer　in　contrast　with　those　in　the　group　with　a　low-RNA　methylation　score.　The　capacity　of　RS　to　predict　whether　or　not　immunotherapy　would　be　beneficial　was　explored　further.　In　the　group　with　a　high-RNA　methylation　score,　the　objective　response　rate　to　the　anti-PD-L1　therapy　was　substantially　greater　compared　to　that　observed　in　the　subgroup　with　a　low-RNA　methylation　score.　Additionally,　there　were　variations　across　various　RS　groups　in　terms　of　clinical　features,　tumor　mutation　burden,　and　the　infiltration　level　of　immune　cells.　After　binary　tree　analysis　and　PCR　verification　of　34　prognostic　genes,　it　is　finally　found　that　the　six　genes　of　MAGOH3P,　TRBJ2_3,　YTHDF1P1,　RP11_323D18.5,　RP11_405M12.2,　and　ADAM30　are　significantly　overexpressed　in　cancer　tissues.　These　genes　can　be　used　as　potential　biomarkers　of　endometrial　cancer　and　provide　data　support　for　precise　immunotherapy　in　UCEC　tumors.　©　2022　Chunli　Dong　et　al.