As for PCA clusters, high Pearson correlation coefficients of gene expression within the cluster were only in case of AKR1C3, CBR1, CBR3 genes (r = 0.64 − 0.77, p-value < 0.05) in LUSC tumor as well as CBR1 and CBR3 (r = 0.72 − 0.86, p-value < 0.05) in ESCA tumor. This evidence concerns the gene AKR1C3 and neoplasm.