Genomic deoxyribonucleic acid was extracted from paraffin embedded tissue using GeneJET Genomic deoxyribonucleic acid Purification Kit (ThermoScientific), according to manufacturer protocol. SNPs polymorphisms of the TCF7L2 (rs7903146, C/T), cancer susceptibility 21 (rs6983267, G/T), and GREM1 (rs1696981, C/T) were identified using a real-time PCR method based on the TaqMan® Genotyping Master Mix (Applied Biosystems) and 20× SNP Genotyping Assay (Applied Biosystems), using a 7500 Fast Real-Time Systems (Applied Biosystems) according to manufacturer procedure. Allelic discrimination was made with the help of 7500 Fast Real-Time PCR software, version 2.3.