PIK3CD and breast cancer: GDC-0032 exhibits the same activity against p110α, p110γ and p110δ, but its inhibitory effect on p110β is 30-fold lower.206 Due to the stronger selectivity of GDC-0032, this drug has shown better efficacy in the treatment of PI3KCA-mutant tumors, with a response rate of 36% among breast cancer patients with PI3KCA-mutant tumors.207 In a phase III clinical trial, GDC-0032 was more effective than fulvestrant,208 and the results showed that the main adverse events after GDC-0032 administration were diarrhea and hyperglycemia.