PDCD1 and neoplasm: Since the high expression levels of PD-L1 were predictive of favorable clinical response to PD-1/PD-L1 inhibitors, the patient who failed tipifarnib treatment was started on a humanized monoclonal PD-L1 antibody, atezolizumab, that is effective in patients with platinum-resistant MIUBC [73, 74] as optimized next-line therapeutic options for the relapsed tumor after tipifarnib treatment.