RAB5A and ductal breast carcinoma in situ: These cells express the oncogenic variant T24‐H‐RAS and provide a model for the progression of DCIS toward invasive ductal carcinoma (IDC),[18] and were engineered to express RAB5A protein in a doxycycline‐inducible manner to levels similar to those found in aggressive human breast tumors.[8, 10, 19] This model system simulates some of the features observed in the progression of in situ breast carcinoma to invasive carcinoma.