ERCC1 and beta tubulin class III (BT-III) expression by quantitative immunofluorescence (IF) in the responder and non-responder group of patients with advanced non-small-cell lung cancer after 2 cycles of cisplatin (P) and vinorelbine (Vn) chemotherapy.

19065 Background: Recent data indicates that ERCC1 expression correlates with platinum responsiveness in adjuvant therapy and in stage IV disease. BT-III expression has been correlated to sensitivity to anti-tubulin agents. We investigated whether ERCC1 and BT-III expression level is correlated with clinical responsiveness in the patients treated with PVn chemotherapy utilizing a novel quantifiable IF method to assess ERCC1 and BT-III expression.,We retrospectively studied 36 patients who received the first line chemotherapy of P 60 mg/m D1 and Vn 25 mg/m D1, D8 q 3 weeks and were categorized into 2 groups of responder(R) and non-responder(nR) (defined as more than partial response and as stable disease or progressive disease, respectively, after 2 cycles of chemotherapy). Paraffin embedded tumor specimens were analyzed by quantitative IF staining for ERCC1 and BT-III expression using anti-ERCC1 (clone 8F1, GeneTex) and anti-beta tubulin class III (clone SDL.3D10, Sigma-Aldrich) respectively. The intensity of IF was measured quantitatively with a digitalized microscopy system (expression level from 0 to 10) and expressed as the mean of the average fluorescence per pixel.,Among 36 patients who received the first line PVn chemotherapy 2 cycles, R was 19 and nR 13 (RR 59%). 32 tumor specimens were available for IF staining, but 26 cases were analyzable by quantitative IF staining (excluded 3 cases each from R and nR). ERCC1 expression in R ranged from 1 to 8 (mean 3.17, SD 1.76) and that in nR ranged from 1.5 to 10 (mean 4.94, SD 2.55, p=0.063). BT-III expression in R ranged from 1 to 9.7 (mean 3.87, SD 2.20) and that in nR ranged from 0.5 to 9.7 (mean 3.08, SD 3.02, p=0.474). R/nR ratio in high(+) ERCC1/high(+)BT-III was 3/1, +/low(-) 3/5, -/+ 5/2, -/- 4/3.,Clinical responsiveness of cisplatin and vinorelbine chemotherapy in the patients with advanced non-small-cell lung cancer was good and we observed a tendency toward correlation between ERCC1 expression and clinical responsiveness but poor correlation in terms of BT-III expression within the limitations of small sample size. No significant financial relationships to disclose.