In addition, previous studies have also reported excessive HSP90AA1 stature in studies of MDR [43], whose client protein mutant p53 (Mut-p53) in malignant tumors reduces drug efficacy (off-target), and it can also activate the transcription factor SP1 (specificity protein 1), which promotes the transcription and expression of MDR1 [44,45]. This evidence concerns the gene ABCB1 and cancer.