GPCR-related publications and the distribution of odorant receptor (OR) gene expression in glioma from the Cancer Genome Atlas. (A) A table describing GPCR genes associated with gliomas in more than two publications. The number in parenthesis represents the number of publications that was found in PubMed. (B) A bar plot showing the OR-expressing sample ratio for each OR gene. The x-axis represents the glioma sample ratio, which is defined by the number of OR-expressing samples divided by the total sample number, and the y-axis represents the number of ORs. (C) A heatmap showing unsupervised clustering of ORs that have highly variable expression levels between samples (standard deviation ≥ 0.3 and expressed in > 33.3% of the total number of samples). (D) A box plot showing OR gene expression levels between the three glioma subtypes. The P-values were calculated from the Student’s t-test. A black dot represents one sample.