Abstract: Phosphorylated Histone γH2AX as a Potential Pharmacodynamic Biomarker for Predicting theSensitivity of Pulmonary Carcinoma to Chemotherapeutic DrugsGuihui ZHANG, Ping ZHOU, He DONG, Qing SUNCorrespondence to: Department of Pathology, Qianfoshan Hospital Affiliated to Shandong University, Ji'nan 250014, ChinaAbstract Objective: To study the feasibility and reliability of using phosphorylated histone H2AX ( γH2AX ) as a biomarkerfor predicting the sensitivity of a pulmonary carcinoma to cisplatin ( DDP ), carboplatin ( CBP ), gemcitabine ( GEM ), and adriamycin( ADM ). Methods: Pulmonary carcinoma cells from the patients were primarily cultured and exposed to the above chemotherapeuticdrugs at different concentration indices ( CI ). The proportion of the pulmonary carcinoma cells with positive expression of γH2AX wasmeasured by flow cytometry and immunocytochemistry, whereas cell proliferation was measured with MTT assay. The difference be-tween the number of γH2AX foci, the percentage of the positive cells that expressed and γH2AX, and the inhibitory rate of cell prolifer-ation were analyzed and their correlations were compared. Results: There was correlation between the number of γH2AX foci, the per-centage of positive cells expressing γH2AX, and the inhibitory rate of cell proliferation after treatment with different CI of the samedrug ( all P < 0.05 ). A correlation was also found among the different drugs ( all P < 0.05 ). Conclusion: Using γH2AX expression forpredicting the pharmacodynamic sensitivity of pulmonary carcinoma to chemotherapy agents is feasible and reliable.Keywords Histone H2AX; Pulmonary carcinoma; Primary cell culture; Chemotherapeutic sensitivity