The estimation of effects of GLCE functional polymorphism A2017G (Ile597Val) on the gene expression levels in normal and breast cancer cells and LOH in breast tumors.
Breast cancer patients (n = 144.) had histologically verified diagnoses. Blood and breast cancer tissue samples as well as matched control tissues were collected from each patient during surgery. Genomic DNA was isolated by phenol extraction. Total RNA was isolated by TRIZol, RNA quantity was accessed by Qubit instrument with appropriate reagents and cDNA was obtained using First Strand cDNA Synthesis kit. SNP A2017G (rs3865014) was analyzed by Custom Real-Time SNP Array and GLCE expression levels were determined using Taq-Man-based Real-Time PCR (Applied Biosystems). Statistical analysis was carried out using a Statistika 9.0 software.
AA genotype carriers had a 2-fold increase in GLCE mRNA levels in tumors compared with control surrounding tissues (0.37 ± 0.77 versus 0.17 ± 0.16, respectively, p < 0.05). Oppositely, AG genotype carriers had a 1.5-fold decrease in GLCE mRNA levels in tumors compared with control surrounding tissues (0.39 ± 0.29 versus 0.58 ± 0.33, respectively, p < 0.05 ). However, in any case,the GLCE expression in both normal tissues and breast tumors was more active in AG genotype carriers than in AA carriers. It is known that LOH is often associated with molecular mechanisms of carcinogenesis, we studied this process for the same patients. According our results, LOH was detected in about 10% of cases (5/52 patients), among which G was lost in 3 patients and A was lost in 2 patients.
The obtained data show a possible association between GLCE Ile597Val polymorphism and breast cancer, although the nature of the association remains ambiguous.