Dynamic Monitoring of Immunotherapy Effectiveness with Different Biomarkers in the Patients with Non-Small Cell Lung Cancer

Non-small cell lung cancer (NSCLC) constitutes about 84% of lung cancer. Hence, increased efforts have been fueled into immunotherapy of NSCLC with immune checkpoint inhibitors (ICIs). ICIs have recently taken off as promising immune-therapeutic methods that have slowed down the progress of NSCLC and equipped patients with survival advantages. However, the long-term respondents tally is less than 20% of the population. This low response rate warrants the need for dynamic biomarkers which will provide insight into the possible response of patients to ICIs. Biomarkers are biological molecules that predict the pathologic state of patients and the potential response they will elicit to ICIs. Predictive biomarkers play a crucial role in analyzing the effects of ICI therapy on patients and potentially filter out patients who will certainly benefit from ICIs. In this way, resources in immunotherapy can be rationalised better and the healthcare system can administer an alternative mode of treatment to the non-responsive group of patients. Thus, precision therapy can be performed according to the possible responsiveness and needs of patients. PD-L1 protein is a popular biomarker that has been analyzed extensively to study the immunotherapy effectiveness of PD-L1 and PD-1 inhibitors. But as a single biomarker, PD-L1 protein levels do have their shortcomings to check for ICI therapy effectiveness. As such, this emphasizes the need for exploration of more biomarkers to be used on prediction grounds. A combination of biomarkers may also be considered for better prediction results. This review serves to highlight the importance of PD-L1 protein in dynamic monitoring of the immunotherapy effectiveness and investigates different novel biomarkers that could be plausible options to monitor immunotherapy effectiveness of NSCLC.