EGFR and pachyonychia congenita: Moreover, the ratio of MIG6 mRNA to miR-200 (MIG6 mRNA/miR-200) was negatively correlated with erlotinib response not only in cancer cell lines with diverse tissue origins in vitro, but also in xenografts derived from PC patients carrying wild-type EGFR in vivo (Izumchenko et al., 2014).