EGFR and adenocarcinoma: A prior study conducted by Yanagawa et al. [30] revealed that EGFR mutations had high frequency among some histological subtypes of adenocarcinoma, including adenocarcinoma in situ (62%), minimally invasive adenocarcinoma (60%), lepidic (77%), papillary (50%), acinar (49%), and micropapillary (43%), but a relatively low frequency in solid (28%) and invasive mucinous adenocarcinoma (0%).