Via RNA sequencing, they showed that the KRASG12D mutation was significantly overrepresented in the basal-like subtype, KRASG12V was isolated to the classical subtype, and SMAD4 expression was significantly higher in the classical subtype compared with the basal-like subtype, which is consistent with the observation that SMAD4 loss confers a more aggressive tumor behavior [39]. This evidence concerns the gene SMAD4 and neoplasm.