PIK3CA and cancer: Class I PI3K is further divided into two subtypes: class 1A (p110α, p110β, p110δ) and 1B (p110γ), the most common type of cancer, is normally activated by RTKs, such as Epidermal Growth Factor Receptor (EGFR), insulin-like growth factor receptor (IGF1-R), and human epidermal growth factor receptor 2 (HER2/neu) (Higgins et al., 2016).