Single nucleotide polymorphisms (SNPs) analysis of CYP2C8, GSTT1, GSTP1, MDR1(A), MDR1(B) and ERCC1 as predictor of survival after weekly paclitaxel for relapsed advanced head & neck cancer patients (AHNCP)
2540 Background: Gene SNPs correlate with survival in cancer patients (pts) treated with chemotherapy (CHM). CYP2C8 and GSTT1, GTSP1 genes are involved in phase 1 and 2 drug cellular metabolisms respectively; MDR1(A) and MDR1(B) are involved in drug membrane transport and ERCC1 in DNA repair Methods: We evaluated the presence of SNPs of these 6 genes and the survival of AHNCP treated with weekly paclitaxel, 80 mg/m2 iv for 6 weeks. Responding pts continue CHM till progression. All pts were cisplatin resistant and no other local therapies were available. We analysed paraffin-embedded biopsies from 47 consecutive AHNCP for SNPs of the mentioned genes. The status of the alleles wild type (wt) or at least 1 SNP was compared with response rate (RR), time to progression (TTP) and overall survival (OS) Results: Of 47 pts, 43 were male and 4 female. The median of age was 57 yr (46–80). RR was 45% (21/47) and the TTP in responders was 5 months of median. OS for all pts was 5.6 months. Wild type vs at least 1 SNPs frequencies according the genes were: CYP2C8 23/24; GSTT1 45/2; GSTP1 36/11; MDR1(A) 21/28; MDR1(B) 13/34; and ERCC1 27/20. OS was significantly better in pts with 2 or more SNPs accumulated (p=0.0455). No other significant differences were observed in RR, TTP or OS in SNPs vs wild type pts. Conclusions: SNPs of CYP2C8, MDR1(A) and MDR1(B) genes were more frequent than wt in our pts. OS was significantly better in pts with 2 or more SNPs accumulated. Paclitaxel provides high rate of responses of short duration in AHNC pts No significant financial relationships to disclose.