[Expression of multidrug resistance gene and its reversion by cyclosporine in non-small cell lung cancer]

To investigate relation between the multidrug resistance gene (MDR1) expression and chemotherapeutic response for non-small cell lung cancer (NSCLC) and to evaluate the effect of cyclosporine (CsA) on reversion of MDR1.

Cancer tissue specimens and peripheral blood samples were collected from 46 patients with NSCLC. MDR1 was amplified in total RNA extracted from cancer cell specimens and peripheral blood lymphocyte (PBL) by RT-PCR assay. According to the result of detection , some MDR1-positive patients were treated with CsA and anticancer drugs (reverse group) , other MDR1-positive patients (positive control group) and MDR1-negative patients (negative control group) were treated with anticancer drugs alone.

The MDR1 positive rate of cancer cells was 65. 2 %(30/ 46) , and of PBL was 58. 7 %(27/ 46) ; twenty-four cases were MDR1-positive both in cancer cells and PBL. The positive rate of patients with recurrence was 81. 3 %(26/ 32) ; of untreated patients was 28. 6 %(4/ 14) ; of patients with multi-cycle chemotherapy was 85. 7 %(24/ 28) ; of patients with non-chemotherapy was 33. 3 %(6/ 18) . The differences were significant ( P < 0. 01) . The response rate was 46. 7 %(7/ 15) in reverse group and 20 %(3/ 15) in positive control group and 37. 5 %(6/ 16) in negative control group. There were no significant differences in the toxicities and immunity changes except for hematological toxicity and impaired liver function between reverse group and other groups.

RT-PCR examination of MDR1 expression is useful for predicting response to chemotherapy and prognosis in NSCLC patients. MDR1-positive is associated with poor prognosis. The reverse effect of CsA for expression of MDR1 requires further clinical study.