Molecular Markers in Guiding Lung Cancer Diagnosis and Treatment

Abstract

Background: Lung cancer has the highest mortality rates and one of the lowest 5-year survival rates amongst cancer types in the world. Although there are constant advancements in treatment, the overall prognosis for lung cancer continues to be poor. In order to achieve early detection and personalized targeted treatment, an effective method is needed to make prognostic and treatment decisions. Methods: A thorough literature search was conducted to identify tumor tissue, blood, and expired breath markers that have been discovered in lung cancer. Articles were chosen by determining main markers holding promise for future clinical use. Results: Data suggests significance in using tumor tissue markers as promising diagnostic, prognostic and predictive of treatment response and outcome. Epidermal Growth Factor Receptor (EGFR) and Anaplastic Lymphoma Kinase (ALK) and ROS-1 biomarkers can be used to decide to treat with EGFR-TKI and ALK-TKI, respectively. KRAS and p53 mutations suggest a likelihood of developing EGFR-TKI resistance. And c-MET is showing pertinence in predicting disease recurrence. Blood and expired breath markers are two more novel sources for biomarkers that is gaining more ground in lung cancer research. Circulating tumor cells (CTC) and DNA (ctDNA) were shown to be important markers in lung cancer prognosis and treatment response prediction. Circulating tumor cells suggest negative prognosis and increased likelihood of recurrence, while ctDNA data indicates use in treatment monitoring to help make decisions without keeping patients on disagreeable therapies. Volatile organic compounds (VOC) are the least studied, but investigators have noticed changes in VOC profiles between healthy and lung cancer patients. Blood and expired breath markers continue to be studied as these would be a welcome alternative to invasive biopsies. Recently there had been interest in using specific tumor biomarkers for imaging to localize tumors and determine disease progression. Conclusions: Years of research have elucidated multiple candidates as biomarkers found in tumor tissues, circulation, and even in exhaled air. Although more studies need to be performed on some markers mentioned in this review, such as EGFR, KRAS, ALK, and ROS-1, there is enough evidence for some use of these biomarkers to guide decisions in clinic, as well as evidence for promising future developments.