Inspired by this concept, we developed a 5-ALA and CAT co-delivery system based on a theranostic microneedle patch (MN-CCPCA) that forces cancer cell to release the false signal of a “heme deficiency” and thus shuts down the outflow of PpIX through the cascaded downregulation of HIF-1α and FECH. The gene discussed is HIF1A; the disease is cancer.