Altogether, the above genetic alterations lead to a unique downstream transcriptional response to oncogenic KRAS in squamous PDAC [35,79], which involve the Hedgehog/WNT (developmental) pathway [10,37,54,57,61,67], EGF [10,55], and other signaling pathways (PI3K-AKT and -mTOR, Hippo) associated with tumor aggressiveness [37,67,68], together with alterations in cell differentiation, proliferation and apoptosis-associated genes (e.g., C-MYC, YAP1, HEY1, and E2F7) [10,37,71,80]. This evidence concerns the gene PIK3CA and neoplasm.