2.7. Analysis of immune infiltration

Gene expression RNA-sequence (TOIL RSEM fpkm, n = 10,535) and phenotype (Curated clinical data, n = 12,591) of TCGA Pan-Cancer (PANCAN) were downloaded from Xena (http://xena.ucsc.edu) [26]. The gencode.v36.annotation.gtf file was downloaded from GENCODE (https://www.gencodegenes.org) to convert TCGA Pan-Cancer expression TPM from ensembl gene id to Symbol, and merge the expression and survival data. According to the data of marker genes of immune cells described by Charoentong et al. [27], the GSVA package (version 1.36.3) in R software (version 4.0.2) was used to perform single-sample gene set enrichment analysis to identify immune infiltration. Finally, the relationship between the immune infiltration and the level of OXTR in TCGA-COAD (n = 329) samples was demonstrated.