Re: Polymorphisms of Death Pathway Genes FAS and FASL in Esophageal Squamous-Cell Carcinoma

Extract

We have read with great interest the recent work by Sun et al. (1) about the role of functional FAS and FASL gene polymorphisms and esophageal squamous- cell carcinoma risk. In addition to the report of Sun et al., polymorphisms of the FAS/FASL system have also been shown to be associated with acute myeloid leukemia (2), cervical cancer (3), and lung cancer (4).

To analyze the role of FAS/FASL polymorphisms for breast cancer, we performed a case–control study that included 500 female breast cancer patients and 500 healthy sex- and age-matched control subjects. The study was approved by the Ethical Committee of the Medical University Graz. Written informed consent was obtained from all participating subjects. All subjects were Caucasian.

FAS –1377G>A, FAS –670A>G, and FASL –844C>T genotypes were determined by a 5′-nuclease assay (TaqMan; Applera Austria Handels, Vienna, Austria). Primer and probe sets were designed and manufactured by the Applied Biosystems Assay-by-Design custom service (Applera Austria Handels). The following sequences of primers and probes were used to detect FAS and FASL polymorphisms: for FAS –1377G>A, forward primer (5′-GCTCAGAGTGTGTGCACAAG-3′), reverse primer (5′-ACTGTTAGTGCCATGAGGAAGAC-3′), G-probe (5′-VIC-CTGGCACGCCCAGG-NFQ-3′, where VIC is the fluorescent dye, NFQ is the nonfluorescent quencher, and the underlined base indicates the polymorphic site), and A-probe (5′- FAM-CTGGCACACCCAGG-NFQ-3′, where FAM is the fluorescent dye); for FAS –670A>G, forward primer (5′-CTATGGCGCAACATCTGTACTTTT-3′), reverse primer (5′-TCCATCTTGTGGCTGCAACAT-3′), G-probe (5′-VICCATTCCAGGAACGTC-NFQ-3′), and A-probe (5′-FAM-CATTCCAGAAACGTC-NFQ-3′); and for FASL −844C>T, forward primer (5′-CCTGGGTGACAGAGTGAGACT-3′), reverse primer (5′-AGGCTGCAAACCAGTGGAA-3′), C-probe (5′-VIC-TTTGTATTTCGCAATGTT-NFQ-3′), and T-probe (5′-FAMCTTTGTATTTCACAATGTT-NFQ-3′). As a quality control, 95 samples were reanalyzed; results were identical for all samples.