PIK3CD and skin cancer: PI3K inhibition was therefore attracted the interest in overcoming the therapeutic resistance in melanoma57–60 and SCC52,61 however, the results obtained were greatly variable and moreover a clinical trial using a mTORC1 inhibitor combined with an EGFR inhibitor did not show significant benefits to the patients52 indicating the need to understand more precisely how the PI3K pathway is involved in skin cancers.