PIK3CA and bladder transitional cell carcinoma: We found that even if the 12 TCGA BLCA cases containing 12 DNA-only somatic mutations had sufficient expression level for the PIK3CA gene (TPM: 23.7–51.7, curated from UCSC Xena(Goldman et al., 2020) dataset), the 12 mutations’ alternative allele still got un-expressed (median alt allele-depth: 0) leading to unlikely benefit from certain targeted therapies.