Influence of apoptosis (BCL2, FAS), cell cycle (CCND1) and growth factor (EGF, EGFR) genetic polymorphisms on survival outcome: an exploratory study in squamous cell esophageal cancer.

The study aimed at investigating whether genetic polymorphisms in BCL2, FAS, CCND1, EGF and EGFR genes influence the outcome of patients of esophageal squamous cell cancer treated with radiotherapy, with or without chemotherapy. Sixty nine histologically confirmed, previously untreated, patients with a squamous cell esophageal cancer were inducted into this study. Genotyping of BCL2 (ala43thr), FAS (A-670G), CCND1 (G870A), EGF (+61A/G) and EGFR (G497A) polymorphisms were determined using the polymerase chain reaction followed by restriction fragment length polymorphism methodology. Genotyped data was analyzed using univariate and multivariate logistic regression statistical tests for predicting the survival outcome. Genotypes of BCL2, FAS, CCND1 and EGFR polymorphisms independently did not influence outcome significantly. However, patients with EGF +61AG genotype had median survival of 25.5 months (95% CI = 5.2-45.5), whereas those with EGF +61GG genotype had survival of only 3.7 months (95% CI = 0.0-9.8, p = 0.006). In univariate cox-regression analysis, interaction of genotypes EGF+61GG*radiotherapy tumor dose (< or =50 Gy) and EGF +61GG *upper third tumor location showed high hazard of death, 6.6 (95% CI = 2.0-21.5, p = 0.002) and 26.8 (95% CI = 3.7-194.2, p = 0.001) while EGF+61AG*middle third tumor location had reduced hazard 0.20 (95%CI = 0.06-0.60, p = 0.004). The pilot study suggests that EGF +61AG and +61GG genotypes may predict clinical outcome in esophageal cancer patients treated with radiotherapy with or without chemotherapy. EGF +61AG genotype was associated with improved survival, however +61GG genotype adversely affected the outcome in patients particularly with upper third location of tumor and lower dose (< or =50) of radiotherapy.