Abstract: Objective To investigate the transcription and protein expression of xeroderma pigmentosum group D (XPD) gene in peripheral blood and skin tissue among endemic arsenism patients caused by coal burning.Methods Totally 110 patients were chosen as case group in endemic arsenism area in Guizhou province and divided into 0-, 2-, and 4-μg/g group based on their hair arsenic contents.Another 36 healthy residents were chosen as control group.The content of hair arsenic was detected with diethyl dithio-carbamate argentine(DDC-Ag) and the mRNA expression level of XPD was detected by real-time fluorescence quantitative PCR.At the same time, 62 skin tissue samples were collected from the volun tary surgical treatment patients with endemic arsenism and were divided in to general pathological changes, precancerous, and cancerous group according to pathological measures.Another 13 cases from nontumor patients were chosen as control group.Skin samples were collected to detect XPD prote in with immuno histochemical method.Results The mRNA levels of XPD were 0.267 5(0.040 3-0.462 6), 0.100 7(0.020 7-0.300 5), and 0.170 7(0.016 9-0.528 0), respectively, among 0-, 2-, and 4-g/g group and were lower than that of the control group(0.759 30.398 2-0.968 7) with statistical differences(P<0.05 for all).The XPD prote in expression of the case was lower than that of the control.There were statistical differences between 2, 4 μg/g group and the control group in the prote in expression.There were statistical differences between the precancerous, cancerous and the control group in the protein expression.Conclusion A rsenic from coal burning may cause abnormal transcription and prote in expression of XPD, which may inhibit DNA repair capacity through affecting damaged DNA unwinding and promote occurrence, development of arsenism and even skin carcinogenesis.