BACKGROUNDThe expressive level of glucose-regulated protein 78 (GRP78) is elevated and correlated with resistance of chemotherapy drugs in breast cancer cell. However, little is known about the relationship between its expression and drug resistance in non-small cell lung cancer (NSCLC). The aim of this study was to explore the relationship between drug resistance and the expression of GRP78 in NSCLC.

METHODSDrug sensitivity test was used to detect the resistance to 8 chemotherapy drugs in 52 NSCLC fresh surgical samples by methylthiazoletrazolium (MTT), and expression of GRP78 was detected by immunohistochemistry method. Spearman correlation assay was used to investigate the correlation between the GRP78 expression and drug resistance.

RESULTSThe resistance rates to paclitaxel (PTX), adriamycin (ADM), carboplatin (CBP), topotecan (TPT), navelbine (NVB), vincristine (VCR), cisplatin (DDP) and etoposide (VP-16) of the 52 samples were 42.31%, 57.69%, 63.46%, 65.38%, 67.31%, 73.08%, 78.85%, 90.38%, respectively. Fourteen cases showed the complete resistance to the total 8 chemotherapy drugs. Furthermore, the expression of GRP78 was stronger in poorly differentiated cancer as compared with the well and moderately differentiated cancer (P < 0.05), so as in stage II and III cancer than in stage I cancer (P < 0.05). Spearman correlation assay showed that there was a correlation between the chemotherapeutics resistance to ADM, VP-16, VCR, TPT and the expression of GRP78 in NSCLC (P < 0.05).

CONCLUSIONSIt is feasible to detect the drug sensitivity to chemotherapy for tumor cells by MTT method. The results of chemosensitivity assay in vitro are indicative of clinical drug administration in NSCLC. The detection of GRP78 isalso indicative of the resistance to chemotherapy drugs and the differentiation and the clinical stage in NSCLC.