Subsequent studies demonstrated that NSCLC cell lines with SULF2M were 134-fold more sensitive to topoisomerase I inhibitor than those with SULF2U. In the current study, we have demonstrated that gastric tumors with SULF2M are more sensitive to irinotecan than those with SULF2U. Furthermore, we demonstrated for the first time that SULF2 methylation is also a potential predictive biomarker for cisplatin efficacy. Here, SULF2 is linked to non-small cell lung carcinoma.