PTK2 and melanoma: Next, we focused on PI3K since it has been reported to have a regulatory role in lung tumors and its interaction with FAK has been well‐documented.[40] Additionally, PI3K signaling was shown to induce melanoma growth in mice upon dietary supplementation of chondroitin sulfate.[11b] To validate the role of PI3K in sulfation‐mediated events, we generated PIK3CA‐knockdown A549 cells (Figure S18, Supporting Information).