CHEK1 and cancer: To determine whether the overexpression of the downstream components of the ATR-CHK1 pathway could have an impact on cancer development, we focused on a cohort of low grade (IA, IB, IIA, and IIB) NSCLCs patients who received no adjuvant treatment and asked whether the expression level of components of the ATR-CHK1 pathway determined at diagnosis had an impact on their disease-free survival (DFS) over a 72 months period.