ID1 and squamous cell carcinoma: A previous study reported that higher Id1 levels were associated with an overall survival in adenocarcinoma but not in squamous cell carcinoma from 346 NSCLC patients[15], however survival analysis using the Kaplan-Meier plotter database (www.kmplot.com, 2014 version) with a log-rank test revealed that increased Id1 expression correlated with poor prognosis in both the adenocarcinoma and squamous cell carcinoma from 1405 NSCLC patients (Fig. 6D and Supplementary Fig. S7C).