Keratin 17 is a Negative Prognostic Biomarker in Non-Small Cell Lung Cancer.

Although the overall prognosis for patients with non-small cell lung cancer (NSCLC) has improved over the past several decades, there are still survival differences that are not accurately defined by clinicopathological factors. Thus, there is an unmet clinical need to develop novel approaches to enhance prognostic accuracy for the assessment of these patients. Prior studies have established that keratin 17 (K17) is a negative prognostic biomarker in a wide range of cancer types, including pulmonary adenocarcinoma (LUAD). Although keratin expression profiles have been widely utilized as markers to distinguish between metastatic versus primary squamous cell carcinomas (SCC), K17 has not been previously investigated for its potential accuracy as a prognostic biomarker in lung squamous cell carcinoma (LSCC). Here, we set out to determine if K17 is a prognostic biomarker that drives poor survival in both LSCC and LUAD. Data mining was performed to analyze K17 mRNA in independent cohorts of LSCC (n=266) and LUAD (n=271) and immunohistochemistry (IHC) for K17 was performed in separate cohorts of LSCC (n=84) and LUAD (n=107). Kaplan-Meier and Cox proportional-hazard regression models were used to determine overall survival differences between low vs. high K17 expressing cases. High K17 mRNA correlated with decreased overall survival in both LSCC (HR: 1.789, p=0.0646) and LUAD (HR: 1.894, p=0.0142). Similarly, by IHC, high K17 correlated with decreased overall survival in LSCC (HR: 1.894, p=0.0375) and LUAD (HR: 2.105, p=0.0257). Thus, K17, defined either by mRNA expression or immunohistochemical staining, is a negative prognostic biomarker for non-small cell lung cancer.