KLK3 and cancer: Even though the majority of patients that seem to derive clinical advantage from the currently available immunotherapeutic strategies markedly fall into localized and/or non-metastatic disease subtypes, there is substantial evidence to suggest that patients with unfavorable characteristics such as predominantly existing metastases may also experience improved outcomes, as seen with cancer vaccines Ad5-PSA and CV9103 and through combinations of ICIs with other treatment modalities.