Objective To examine the expression of heat shock protein (HSP) 90 β in human gastric cancer tissue and SGC7901/VCR of MDR type gastric cancer cell line Methods Immunohistochemical staining and in situ hybridization methods Results Heat shock protein 90 β was mainly located in the cell cytoplasma and weakly expressed in non cancerous gastric mucosa The expression rates of HSP90 β in normal gastric mucosa, gastritis and para cancer tissues were 11 76%, 13 04% and 11 42% respectively,and there were no significant differences between them ( P >0 05) The expression of HSP90 β was increased in gastric cancer The positive rate of HSP90 β in gastric cancer tissue was 30 00%, and was higher than non cancerous gastric mucosa ( P <0 05) The expression rates of HSP90 β in well differentiated, moderately differentiated, poorly differentiated gastric cancer and mucinous carcinoma were 15 38%, 31 25%, 33 33%, and 42 85% respectively The expression of HSP90 β in SGC7901/VCR of MDR type gastric cell line was higher than in its parental cell line SGC7901 In situ hybridization showed that the positive signal of HSP90 β was mainly located in the cell cytoplasma Conclusions The expression of HSP90 β was higher in gastric cancer tissue than in non cancerous gastric mucosa In gastric cancer tissue, the expression of HSP90 β was greater in poorly differentiated cancer tissue, and in SGC7901/VCR of MDR type gastric cancer cell line the expression of HSP90?β was higher than that in its parental cell line SGC7901 Objective To treat the expression of heat shock protein (HSP) 90 β in human gastric cancer tissue and SGC7901/VCR of MDR type gastric cancer cell line Methods Immunohistochemical staining and in situ hybridization tools Results Heat shock protein 90 β was mainly located in the cell Cytoplasma and weakly expressed in non cancerous gastric mucosa The expression rates of HSP90 β in normal gastric mucosa, gastritis and para cancer tissues were 11 76%, 13 04% and 11 42% respectively, and there were no significant differences between them ( P > 0 05) The expression of HSP90 β was increased in gastric cancer The positive rate of HSP90 β in gastric cancer tissue was 30 00%, and was higher than non cancerous gastric mucosa ( P <0 05) The expression rates of HSP90 β in well Differentiated, moderately differentiated, poorly differentiated gastric cancer and mucinous carcinoma were 15 38%, 31 25%, 33 33%, and 42 85% respectively of the expression of HSP90 β i n SGC7901/VCR of MDR type gastric cell line was higher than in its parental cell line SGC7901 In situ was classified that the positive signal of HSP90 β was mainly located in the cell cytoplasma concludes the expression of HSP90 β was higher in gastric cancer tissue than In non cancerous gastric mucosa In gastric cancer tissue, the expression of HSP90 β was greater in poorly differentiated cancer tissue, and in SGC7901/VCR of MDR type gastric cancer cell line the expression of HSP90?β was higher than that in its parental cell line SGC7901