Characterization of the mechansims involved in resistance to EGFR inhibitors

We generated patient cSCC-derived xenografts (cSCC-PDXs) that recapitulate the histopathologic and molecular features of parental patient samples. Response to gefitinib treatment was tested in four independent models. cSCC34-PDXs showed intrinsic resistance to gefitinib, whereas three models (cSCC10-PDXs, cSCC16-PDXs and cSCC24-PDXs) initially showed a strong response to gefitinib, but acquired resistance after long-term treatment. RNA sequencing analysis were performed in matched untreated and gefitinib-resistant cSCC-PDXs to determine mechanisms behind gefitinib resistance. RNA sequencing of control (treated with vehicle solution) cSCC-PDXs vs gefitinib-resistant cSCC-PDXs from four different patients