It has been shown in a variety of malignant tumors including lung cancer that ALDH is a CSC marker.34, 35 We demonstrate in this study that the NSCLC subset with an augmented ALDH activity (ALDHhigh) indeed possesses an elevated level of stem cell genes, an elevated clonogenic capacity and, importantly, a greater chemoresistance to MTA (Figure 1). Here, LDHA is linked to lung cancer.