Expression and Prognostic Significance of c-Myc, ALK, ROS1, BRAF, and PD-L1 Among Patients With Non-Small Cell Lung Cancer

BACKGROUND: Non-small cell lung cancer (NSCLC) remains a leading cause of cancer death worldwide, for which better knowledge in molecular prognostic factors is needed to improve clinical outcome. This study aimed to investigate the clinical significance of c-Myc, ALK, ROS1, BRAF, and PD-L1 in NSCLC patients. METHODS: Formalin-fixed paraffin-embedded tissue specimens were obtained from 124 NSCLC patients. Of these, 66 matched specimens of normal respiratory epithelial and tumor tissue from patients with stages I-III, who underwent surgical resection, and 58 NSCLC specimens from stage IV patients were recruited into this analysis. Immunohistochemistry staining along with semiquantitative criteria were used to evaluate the expression of the interested proteins. RESULTS: Of the 66 patients with stages I-III, positive expression of c-Myc was detected in 12 specimens (18.2%) of NSCLC tissue, whereas none of the normal respiratory epithelial tissue was found to have c-Myc expression (P < .001). Of the 66 NSCLC patients, 28 (43.8%) had PD-L1-positive staining on 1%-49% tumor cells and 7 (10.9%) patients expressed PD-L1 in ⩾50% tumor cells. One (2.3%) adenocarcinoma patient was found to have ROS1 rearrangement. Patients with no expression of c-Myc and PD-L1 (co-negative expression) tended to have a better prognosis than other subgroups. CONCLUSIONS: NSCLC tissue significantly expressed more c-Myc and PD-L1, compared with the matched normal respiratory epithelium, emphasizing the important role of these key drivers in tumorigenesis. Therapeutic approach to precisely inhibit the targetable molecular pathways should be considered on an individual patient basis to improve survival outcome.