The solid component rate was significantly higher in Wt tumors than in Ex19 and Ex21 tumors; this is consistent with previous studies in which adenocarcinoma with a solid histologic subtype was strongly associated with KRAS mutations37,38 and was rare in Mt tumors.15 Unlike previous studies in which the papillary histologic subtype was associated with Mt tumors,26 we observed that the papillary growth pattern was more frequently found in Wt tumors in this study. This evidence concerns the gene KRAS and adenocarcinoma.