The expression of chemoresistance genes has been detected, including KLF4 (doxorubicin and ifosfamide), ULK1, LUM, GPNMB, and CAVIN1 (doxorubicin), and AHNAK2 (gemcitabine) in tumor cells and ETS1 (gemcitabine) in TME. This evidence concerns the gene KLF4 and neoplasm.