Genetic alterations or ultraviolet (UV) exposure results in the dysregulation of the PI3K/Akt/mTOR pathway in melanocytes, basal cells, squamous cells, or Merkel cells, which leads to the development of melanoma, basal cell carcinoma, cutaneous squamous cell carcinoma, or Merkel cell carcinoma [33]. Here, PIK3CA is linked to melanoma.