OBJECTIVE: To study the multidrug resistance (MDR) of non-small lung cancer (NSCLC) and its relationship with neuroendocrine (NE) differentiation. METHODS: NSCLC samples from 113 untreated patients were analyzed immunohistochemically with antibodies to glutathion-s-transferase-pi (GST-pi), multidrug resistance associated protein (MRP), lung resistance associated protein (LRP), neuro-specific enolase (NSE), synaptophysin (SYN) and chromogranin (CgA). RESULTS: (1) The expression of the three proteins was significantly associated with the type of lung carcinoma (P < 0.05), but not with the differentiation and lymph node metastasis. The expression of GST-pi was significantly related with MRP, MRP and LRP (P < 0.05). (2) The positive rates of the NE markers were: NSE, 53.1%; SYN, 26.6%; CgA, 6.2%; and 21.2% for at least two markers. The expression of at least 2 markers was associated with the degree of differentiation (P < 0.05), but not with the type of lung cancer and lymph node metastasis. (3) The expression of the three multidrug resistance related proteins in the positive group for at least 2 markers was significantly lower than that in the negative group (P < 0.05). CONCLUSIONS: The over-expressions of GST-pi, MRP and LRP are important causes of primary multidrug resistance in NSCLC. The differentiation of NE may be one of the factors involved in multidrug resistance.
OBJECTIVE: To study the multidrug resistance (MDR) of non-small lung cancer (NSCLC) and its relationship with neuroendocrine (NE) differentiation. METHODS:NSCLC samples from 113 untreated patients were analyzed immunohistochemically with antibodies to glutathion-s-transferase-pi (GST-pi), multidrug resistance associated protein (MRP), lung resistance associated protein (LRP), neuro-specific enolase (NSE), synaptophysin (SYN) and chromogranin (CgA). RESULTS: (1) The expression of the three proteins was significantly associated with the type of lung carcinoma (P < 0.05), but not with the differentiation and lymph node metastasis. The expression of GST-pi was significantly related with MRP, MRP and LRP (P < 0.05). (2) The positive rates of the NE markers were: NSE, 53.1%; SYN, 26.6%; CgA, 6.2%; and 21.2% for at least two markers. The expression of at least 2 markers was associated with the degree of differentiation (P < 0.05), but not with the type of lung cancer and lymph node metastasis. (3) The expression of the three multidrug resistance related proteins in the positive group for at least 2 markers was significantly lower than that in the negative group (P < 0.05). CONCLUSIONS: The over-expressions of GST-pi, MRP and LRP are important causes of primary multidrug resistance in NSCLC. The differentiation of NE may be one of the factors involved in multidrug resistance.