These biomarker candidates include Cathepsim-D [27], L-lactate dehydrogenase B chain (LDHB) [28], translationally controlled tumor protein (TCTP) [29], triose phosphate isomerase (TPI) [29], dihydrodiol dehydrogenase (DDH) [30], etc. However, QSOX1 has never been discovered in the secretome analysis of lung cancer cell lines. Here, AKR1C1 is linked to lung cancer.