Based on the comparison between the hub genes, hypoxic and oxic signatures, TNF, STAT3, CTNNB1, and MYC were screened for BC, IL1B, CTNNB1, ESR1, and SRC were screened for PC, CTNNB1, BRCA1, JUN, and KRAS was screened for OC and PIK3CA, PTEN, and ESR1 was screened for EC for further expression and survival analysis. The gene discussed is PIK3CA; the disease is breast cancer.